Handy well-known and lesser-known tools for Go projects
Know some cool tool or one-liner? Have a feature request or an idea?
Feel free to edit this page or create an Issue!
- AI tools
- Testing
- 🔥 Continuous Tests Monitoring with
codecov.io - Make treemap of coverage with
go-cover-treemap - Browse coverage
- Browse coverage with
gocov-html - Browse coverage in terminal with
gocovsh - Pretty print coverage in terminal with
nikandfor/cover - Run coverage collector server with
goc - Visualize live coverage in VSCode with
goc - 🔥 Shuffle tests
- Run tests sequentially
- Run tests in parallel
- Detect goroutine leaks with
goleak - Detect goroutine leaks with
leaktest - Summarize
go testwithtparse - Decorate
go testwithrichgo - Decorate
go testwithgotest - Decorate
go testwithgotestsum - Format
go testresults as documentation withgotestdox - Get slowest tests with
gotestsum - Auto-Instrument skipping slowest tests with
gotestsum - Automatically re-run failed tests with
gotestsum - Make
JSUnittest report withgotestsum - Make
JSUnittest report withgo-junit-report - Get packages without tests
- Perform Mutation Testing with
ooze - Perform Mutation Testing with
avito-tech/go-mutesting - Perform Mutation Testing with
go-mutesting - Trace tests with
go-test-trace - Speedup tests for large codebases
- 🔥 Continuous Tests Monitoring with
- Dependencies
- Get Go version of current module
- Get Go versions of upstream modules
- Get directly dependent modules that can be upgraded
- Get upstream modules without Go version
- Get available module versions
- Make graph of upstream modules with
modgraphviz - Make graph of upstream modules with
gmchart - Make graph of upstream packages with
import-graph - Scrape details about upstream modules and make graph with
import-graph - Scrape licenses of upstream dependencies with
go-licenses - Explore dependencies with
goda - Explore dependencies interactively with
spaghetti - Use
go moddirectives - Enforce Go code architecture with
go-arch-lint
- Code Visualization
- Make C4 diagram with
go-structurizr - Make graph of function calls with
callgraph - Make graph of function calls in package with
go-callvis - Make PlantUML diagram with
goplantuml - Make PlantUML diagram with
go-plantuml - Make 3D chart of Go codebase with
gocity - Make histogram of Go files per package
- Explore Go code in browser powered by
go-guruwithpythia - 🏚️ Interactively visualize packages with
goexplorer - Make D2 graph of architecture and dependencies with
go-arch-lint graph
- Make C4 diagram with
- Code Generation
- Run
go:generatein parallel - Generate
Stringmethod for enum types - Generate enums encoding with
go-enum-encoding - Generate enums with
goenums - 🔥 Generate data types from JSON Schema with
go-jsonschema - 🔥 Generate constructor for a struct with
gonstructor - Generate Table Driven Tests with
gotests - Generate mocks with
mockgen - Generate interface for a struct with
ifacemaker - Generate interface for a struct with
interfacer - Generate interface for a struct with
struct2interface - Generate interface for
CSVfile withstructer - Modify struct field tags with
gomodifytags - Generate code from OpenAPI 3 specification with
oapi-codegen
- Run
- Refactoring
- Errors
- Building
- Show compiler optimization decisions on heap and inlining
- Disable inlining
- Aggressive inlining
- Profile-guided optimization
- Manually disable or enable
cgo - Include metadata in binary during compilation with
ldflags - Visualise dependencies size in compiled binaries with
go-size-analyzer - Make treemap breakdown of Go executable binary with
go-binsize-treemap - Custom import path
- Custom import path with
govanityurls - Custom import path with
sally - Custom import path with
kkn.fi/vanity - Custom import path enforcement
- 🔥 Manage multiple Go versions with
Goenv
- Assembly
- Get assembly of Go code snippets online
- Get Go SSA intermediary representation with
ssaplayground - View Go assembly interactively with
lensm - 🔥 View Go assembly with color annotation with
pat/disfunc - Generate Go assembly in Go with
avo - Generate AST for code snippets with
go/ast - Generate AST for code snippets with
go2ast - Visualize Go SSA function using Graphviz with
go-ssaviz - 🏚️ Make graph of AST with
astgraph - 🏚️ Convert C assembly to Go assembly with
c2goasm
- Execution
- Embed Go Playground to your blog with
goplay - Run alternative Go Playground with
goplay.tools - Run interactive Go kernels in Jupyter Notebook with
gophernotes - Run interactive Go interpreter with
yaegi - Run interactive Go interpreter with
gomacro - Run Go function in shell with
gorram - Run Go function in shell with
gosh - Run simple fileserver with
net/http - Create 3D visualization of concurrency traces with
gotrace - Wrap command with
os/exec - Capture output of command to file with
os/exec - Capture output of command and process it with
os/exec - Piping between processes with
os/exec -
errgroupand CommandContext withos/exec
- Embed Go Playground to your blog with
- Monitoring
- Monitor goroutines with
grmon - Monitor Go processes with
gops - Visualise Go runtime metrics in browser with
statsviz - Auto-Instrument all functions with
go-instrument - Auto-Instrument all functions with
otelinji - 🔥 Auto-Instrument functions for DataDog with
orchestrion - Continious Profiling with
Pyroscope
- Monitor goroutines with
- Benchmarking
- Run benchmarks
- Table-driven benchmarks
- Generate benchmak CPU and Memory profiles with
go test - Visualize callgraph of profiles with
pprof - Visualize flamegraphs of profiles with
pprof - Visualize profiles online
- Get delta between two benchmarks with
benchstat - Get summary of benchmarks with
benchstat - 🔥 Benchmark against git commit with
pat/ba - Continuous benchmarking
- Continuous benchmarking with
gobenchdata - Continuous benchmarking with
benchdiff - Continuous benchmarking with
cob - Generate live traces with
net/http/trace - Generate traces with
go test - View traces with
go tool trace - Get wallclock traces with
fgtrace - Get on/off CPU profiles with
fgprof - Collect and visualize in-process traces with
trc
- Documentation
- Education
- Style Guide
- Security
- Static Analysis
- Run default static analysis with
go vet - Run custom static analysis tool with
go vet - Run official static analyzers not included in
go vet - Detect most common issues with
staticcheck - 🔥 Detect potential Nil panics with
nilaway - Detect most common issues with
go-critic - Reference and run common linters with
golangci - Detect non-exhaustive switch and map with
exhaustive - Detect structs with uninitialized fields with
go-exhaustruct - Detect unsafe code with
go-safer - Detect unnecessary type conversions with
unconvert - Detect global variables with
gochecknoglobals - Detect slices that could be preallocated with
prealloc - Detect unnecessary import aliases with
unimport - Detect unexpected import aliases with
importas - Detect inconsistent import aliases with
consistentimports - Detect naked returns with
nakedret - Detect mixing pointer and value method receivers with
smrcptr - Detect vertical function ordering with
vertfn - Detect vertical symbol ordering with
refdir - Detect tests with wrong
t.Parallel()usage withparalleltest - Detect tests with wrong
t.Parallel()usage withtparallel - Detect magic numbers with
mnd - 🔥 Detect magic strings with
goconst - 🔥 Detect bound checks with
pat/boundcheck - Calculate Cognitive Complexity with
gocognit - Calculate Cyclomatic Complexity with
gocyclo - Calculate Cyclomatic Complexity with
cyclop - Calculate age of comments with
go-commentage - 🏚️ Ensure
ifstatements using short assignment withifshort - Visualize struct layout with
structlayout - Rely on compiler for stricter Enums
- Analyze function callsites with
go-callsite-stats
- Run default static analysis with
Start typing and after few seconds you will get autocompletion suggestion. Some useful ways to interact with it listed bellow.
given a function signature and docstring, it will suggest function body
given a function body, it will suggest docstring
Requirements
VSCode
GitHub account
CopilotX has dedicated solutions for: writing PR description; writing tests; writing PR reviews and replies; applying requested PR changes. As of 2023-06-04, it is on waitlist. documentation.
⏫ Code analysis and recommendations with charmbracelet/mods
This is a nice looking CLI wrapper for major LLM APIs from Charm team. It supports OpenAI and LocalAI. It passes arbitrary human language command string and concatenated with STDIN input. Multiple useful commands are possible.
mods -f "what are your thoughts on improving this code?" < main.go | glow
mods -f "you are an expert Go programmer. find potential bugs in following Go code." < my_class.go | glow
Requirements
# OpenAI token or LocalAI model and server
go install github.com/charmbracelet/glow@latest
go install github.com/charmbracelet/mods@latest
⏫ Pull request recommendations with gpt-pullrequest-updater
This tool generates GitHub pull request description and review using OpenAI ChatGPT. There is also GitHub Action available. — @ravilushqa
Requirements
# OpenAI token
# GitHub token
go install github.com/ravilushqa/gpt-pullrequest-updater/cmd/description@latest
go install github.com/ravilushqa/gpt-pullrequest-updater/cmd/review@latest
⏫ Commit message recommendation
Short summaries of changes usually work well.
git diff | mods "summarize following git diff into short git commit message."
git diff | mods "you are expert Go programmer. you are owner of this codebase. think through step by step. summarize following git diff into short git commit message under 10 words."
Example
Add new entries for Using AI in Go projects, including Advanced autocompletion with Copilot and Code analysis and recommendations with charmbracelet/mod. Update page.yaml accordingly.
Requirements
# OpenAI token or LocalAI model and server
go install github.com/charmbracelet/mods@latest
⏫ Test case recommendation
Concatenate two files and ask to recommend missing test cases. It is not precise, has high false positive and high false negative rate. Often can not detect that tests cases are present at all. However, it can give a fresh perspective on your code. Best results are produced when asking succinct short replies. Example outputs bellow.
cat fpdecimal.go fpdecimal_test.go | head -c 3600 | mods -f "you are an expert Go programmer. investigate supplied Go program and associated test suite. think through this step by step. make sure you get the right answer. recommend missing test cases. write very succinctly. under 100 words." | glow
cat fpdecimal.go fpdecimal_test.go | head -c 4000 | mods -f "investigate supplied Go program and associated test suite. recommend missing test cases." | glow
Example
For additional test cases, consider adding tests for negative float values, positive and negative infinity, unsigned
integers, zero divided by a number greater than zero, and division with only zeros.
------------------
Test cases:
• Test for unmarshalling JSON into Decimal
• Test for marshalling Decimal to JSON
• Test for multiplication with zero
• Test for multiplication identity
• Test for division with zero
• Test for all comparison operations for the Decimal struct.
------------------
Missing test cases for the fpdecimal Go program include those for testing the DivMod and FromString functions.
Additionally, there should be tests checking that zero division is not allowed, and tests that ensure the
FractionDigits value does not change during the program's runtime. Important test cases include comparing decimals
for equality, as well as testing the commutativity, associativity, and identity properties of addition and
multiplication. Finally, the program should have a test that verifies the MarshalJSON and UnmarshalJSON
functions.
⏫ Time complexity estimate
This is one of recommended use cases by OpenAI website. It can produce fairly good estimations. However, in its direct form usefulness is questionable, since complex cases are not handled precisely enough, educational potential is limited, and simple cases do not require this. Perhaps, this will be utilized in future work on using models in compiler and programming. Copy function and pipe it to model with prompt asking for time complexity estimation. Bellow is an example.
pbpaste | mods -f "calculate time complexity of following Go code function." | glow
func AppendFixedPointDecimal(b []byte, v int64, p int) []byte {
if v == 0 {
return append(b, '0')
}
if p == 0 {
return strconv.AppendInt(b, v, 10)
}
if v < 0 {
v = -v
b = append(b, '-')
}
s := len(b)
b = strconv.AppendInt(b, v, 10)
if len(b)-s > p {
i := len(b) - p
b = append(b, 0)
copy(b[i+1:], b[i:])
b[i] = '.'
} else {
i := 2 + p - (len(b) - s)
for j := 0; j < i; j++ {
b = append(b, 0)
}
copy(b[s+i:], b[s:])
copy(b[s:], []byte(zeroPrefix[:i]))
}
return b
}Example
The time complexity of the AppendFixedPointDecimal function is O(N), where N is the length of the input byte slice
b. This is because the function performs a constant number of operations for each byte in b, and the largest
operation within the function is the loop that appends zeros to the byte slice, which has a length proportional to
the input. Other operations, such as integer conversions and comparisons, are considered constant time since the
input size is fixed.
------------------
The time complexity of the function depends on the input values v and p .
• The first three if statements before the main computation take constant time,
so they don't contribute to the overall time complexity.
• The strconv.AppendInt function used twice has a time complexity of
O(log(v)), where v is the integer being converted to a string representation in
base 10.
• The condition len(b)-s > p has a constant time complexity.
• The append and copy operations inside the if and else blocks take linear
time proportional to p .
• The for loop has a constant number of iterations, specifically 2 + p - (
len(b)-s ). The append and copy operations inside the loop also take linear
time proportional to p .
Therefore, the overall time complexity of the function is O(log(v) + p).
⏫ 🔥 Continuous Tests Monitoring with codecov.io
Track tests duration, errors, flackiness. Run JUnit test output converter and submit result to codecov.io via GitHub Action. — https://codecov.io
go test -coverprofile=coverage.out -cover -json ./... | gotestsum --junitfile tests.xml
Requirements
go install gotest.tools/gotestsum@latest
⏫ Make treemap of coverage with go-cover-treemap
Visualize distribution of code coverage in your project. This helps to identify code areas with high and low coverage. Useful when you have large project with lots of files and packages. This 2D "image-hash" of your project should be more representative than a single number. Also available at https://go-cover-treemap.io. — @nikolaydubina
go test -coverprofile cover.out ./...
go-cover-treemap -coverprofile cover.out > out.svg
Requirements
go install github.com/nikolaydubina/go-cover-treemap@latest
⏫ Browse coverage
This is very helpful tool from the official Go toolchain. Similar visualization is integrated into VSCode and Goland, but can be used separately.
go test -coverprofile cover.out ./...
go tool cover -html=cover.out
⏫ Browse coverage with gocov-html
Browse code coverage in statically generated HTML page. Multiple styles are supported. You may need to convert coverage report into gocov format. — @matm
gocov test strings | gocov-html -t golang > strings.html
gocov test encoding/csv strings | gocov-html -t kit > strings.html
gocov test strings|./gocov-html -cmax 90 > strings.html # show functions with <90% coverage
Requirements
go install github.com/axw/gocov/gocov@latest
go install github.com/matm/gocov-html/cmd/gocov-html@latest
Browse code coverage similarly to HTML provided by official Go toolchain, but in terminal. Other notable features are package level statistics, coverage only for changed files. — @orlangure
go test -cover -coverprofile coverage.out
gocovsh # show all files from coverage report
git diff --name-only | gocovsh # only show changed files
git diff | gocovsh # show coverage on top of current diff
gocovsh --profile profile.out # for other coverage profile names
Requirements
go install github.com/orlangure/gocovsh@latest
⏫ Pretty print coverage in terminal with nikandfor/cover
It is similar to go tool cover -html=cover.out but in terminal. You can filter by functions, packages, minimum coverage, and more. — @nikandfor
cover
Requirements
go install github.com/nikandfor/cover@latest
This tool allows to collect coverage as soon as code is executed. — @qiniu
goc server
goc build
goc profile
Requirements
go install github.com/qiniu/goc@latest
Official Go VSCode plugin already has coverage highlighting. In addition to that, this tool shows covered lines as soon as they are executed. This can be useful for running manual integration or system tests or debugging. — @qiniu
Requirements
go install github.com/qiniu/goc@latest
⏫ 🔥 Shuffle tests
This is less known option that is disabled by default. However, for robust test suite it is beneficial. More test flags and full description is available at go help testflag.
go test -shuffle=on
⏫ Run tests sequentially
Use when you need to synchronize tests, for example in integration tests that share environment. Official documentation.
go test -p 1 -parallel 1 ./...
⏫ Run tests in parallel
Add t.Parallel to your tests case function bodies. As per documentation, by default -p=GOMAXPROCS and -parallel=GOMAXPROCS when you run go test. Different packages by default run in parallel, and tests within package can be enforced to run in parallel too. Make sure to copy test case data to new variable, why explained here. Official documentation.
...
for _, tc := range tests {
tc := tc
t.Run(tc.name, func(t *testing.T) {
t.Parallel()
...Instrument your test cases with verification call. Alternatively, you can add single call in TestMain. This tool was recommended by Pyroscope in blog. — Uber
func TestA(t *testing.T) {
defer goleak.VerifyNone(t)
...
}Requirements
go get -u go.uber.org/goleak
Refactored, tested variant of the goroutine leak detector found in both net/http tests and the cockroachdb source tree. You have to call this library in your tests. — @fortytw2
func TestPoolContext(t *testing.T) {
ctx, cancel := context.WithTimeout(context.Background(), time.Second)
defer cancel()
defer leaktest.CheckContext(ctx, t)()
go func() {
for {
time.Sleep(time.Second)
}
}()
}
This lightweight wrapper around STDOUT of JSON of go test will nicely render colorized test status, details of failures, duration, coverage, and package summary. — @mfridman
set -o pipefail && go test ./... -json | tparse -all
Requirements
go install github.com/mfridman/tparse@latest
Add colors and enrich go test output. It can be used in CI pipeline and has lots of alternative visualizations and options. — @kyoh86
richgo test ./...
Requirements
go install github.com/kyoh86/richgo@latest
Add colors to go test output. Very lightweight wrapper around go test STDOUT. — @rakyll
gotest ./...
Requirements
go install github.com/rakyll/gotest@latest
This wrapper around go test renders test output in easy to read format. Also supports JUnit, JSON output, skipping slow tests, running custom binary. — @dnephin
gotestsum --format dots
Requirements
go install gotest.tools/gotestsum@latest
Decorates go test results by converting CamelCaseTestNames into readable sentences. — @bitfield
gotestdox ./...
Requirements
go install github.com/bitfield/gotestdox/cmd/gotestdox@latest
This is subcommand of gotestsum that processes JSON output of go test to find slowest tests. — @dnephin
go test -json -short ./... | gotestsum tool slowest --threshold 500ms
Example
gotest.tools/example TestSomething 1.34s
gotest.tools/example TestSomethingElse 810ms
Requirements
go install gotest.tools/gotestsum@latest
This is subcommand of gotestsum that processes JSON output of go test to find slowest tests and instruments test cases to skip them with t.Skip() statements. — @dnephin
go test -json ./... | gotestsum tool slowest --skip-stmt "testing.Short" --threshold 200ms
Example
gotest.tools/example TestSomething 1.34s
gotest.tools/example TestSomethingElse 810ms
Requirements
go install gotest.tools/gotestsum@latest
Other useful option of gotestsum is to re-run failed tests. For example, if you have flaky tests that are idempotent, then re-running them may be a quick fix. — @dnephin
gotestsum --rerun-fails --packages="./..."
Requirements
go install gotest.tools/gotestsum@latest
JUnit is widely used format for test reporting. — @dnephin
go test -json ./... | gotestsum --junitfile unit-tests.xml
Requirements
go install gotest.tools/gotestsum@latest
⏫ Make JSUnit test report with go-junit-report
JUnit is widely used format for test reporting. Go benchmark output is also supported. — @jstemmer
go test -v 2>&1 ./... | go-junit-report -set-exit-code > report.xml
Requirements
go install github.com/jstemmer/go-junit-report/v2@latest
⏫ Get packages without tests
If code coverage does not report packages without tests. For example for CI or quality control.
go list -json ./... | jq -rc 'select((.TestGoFiles | length)==0) | .ImportPath'
Example
github.com/gin-gonic/gin/ginS
github.com/gin-gonic/gin/internal/json
Requirements
https://stedolan.github.io/jq/download/
Mutation testing is a technique used to assess the quality and coverage of test suites. It involves introducing controlled changes to the code base, simulating common programming mistakes. These changes are, then, put to test against the test suites. A failing test suite is a good sign. It indicates that the tests are identifying mutations in the code—it "killed the mutant". If all tests pass, we have a surviving mutant. This highlights an area with weak coverage. It is an opportunity for improvement. — @gtramontina
go test -v -tags=mutation
Requirements
go get github.com/gtramontina/ooze
⏫ Perform Mutation Testing with avito-tech/go-mutesting
This is fork of zimmski/go-mutesting. It has more mutators and latest updates. — @vasiliyyudin
go-mutesting ./...
for _, d := range opts.Mutator.DisableMutators {
pattern := strings.HasSuffix(d, "*")
- if (pattern && strings.HasPrefix(name, d[:len(d)-2])) || (!pattern && name == d) {
+ if (pattern && strings.HasPrefix(name, d[:len(d)-2])) || false {
continue MUTATOR
}
}Requirements
go install github.com/avito-tech/go-mutesting/cmd/go-mutesting@latest
⏫ Perform Mutation Testing with go-mutesting
Find common bugs source code that would pass tests. This is earliest tool for mutation testing in Go. More functions and permutations were added in other mutation Go tools it inspired. — @zimmski
go-mutesting ./...
for _, d := range opts.Mutator.DisableMutators {
pattern := strings.HasSuffix(d, "*")
- if (pattern && strings.HasPrefix(name, d[:len(d)-2])) || (!pattern && name == d) {
+ if (pattern && strings.HasPrefix(name, d[:len(d)-2])) || false {
continue MUTATOR
}
}Requirements
go install github.com/zimmski/go-mutesting/cmd/go-mutesting@latest
⏫ Trace tests with go-test-trace
Collect test execution as distributed traces. This is useful for tracking test duration, failures, flakiness. You distributed tracing storage, search, UI, exploration, dashboards, alarms — all will automatically become test status collection. If you run integration tests in your CI, then it is particularly handy to investigate your integration tests same way as real requests, such as Go processes, databases, etc. However, if you do not have distributed traces, it is still useful for adhoc investigations. This tool processes STDOUT of go test. No automatic instrumentation is done. — @rakyll
go-test-trace ./...
Requirements
# open telemetry collector
# traces UI (Datadog, Jaeger, Honeycomb, NewRelic)
go install github.com/rakyll/go-test-trace@latest
⏫ Speedup tests for large codebases
As of 2023-12-11, large codebases may be slow to run tests by default commands. Compiling package test binaries first and executing them later can lead to significant overall speedup.
go test -c ./pkg/mypackage -o my_pkg_test_binary.bin
./my_pkg_test_binary.bin | ... # normal test output post processing
⏫ Get Go version of current module
For example, setup correct Go version automatically from go.mod in CI.
go mod edit -json | jq -r .Go
Requirements
https://stedolan.github.io/jq/download/
⏫ Get Go versions of upstream modules
Use this when upgrading version of Go or finding old modules.
go list -deps -json ./... | jq -rc 'select(.Standard!=true and .Module.GoVersion!=null) | [.Module.GoVersion,.Module.Path] | join(" ")' | sort -V | uniq
Example
1.11 github.com/ugorji/go/codec
1.11 golang.org/x/crypto
1.12 github.com/golang/protobuf
Requirements
https://stedolan.github.io/jq/download/
⏫ Get directly dependent modules that can be upgraded
Keep your modules updated. Similar function is integrated in VSCode official Go plugin and GoLand.
go list -u -m $(go list -m -f '{{.Indirect}} {{.}}' all | grep '^false' | cut -d ' ' -f2) | grep '\['
Example
github.com/goccy/go-json v0.5.1 [v0.7.3]
github.com/golang/protobuf v1.3.3 [v1.5.2]
github.com/json-iterator/go v1.1.9 [v1.1.11]
⏫ Get upstream modules without Go version
Find outdated modules or imports that you need to upgrade.
go list -deps -json ./... | jq -rc 'select(.Standard!=true and .Module.GoVersion==null) | .Module.Path' | sort -u
Example
github.com/facebookgo/clock
golang.org/x/text
gopkg.in/yaml.v2
Requirements
https://stedolan.github.io/jq/download/
⏫ Get available module versions
This works even if you did not download or install module locally. This is useful to check to which version you can upgrade to, what is the latest version, and whether there are v2+ major versions recognized by Go toolchain.
go list -m -versions github.com/google/gofuzz
⏫ Make graph of upstream modules with modgraphviz
For each module, the node representing the greatest version (i.e., the version chosen by Go's minimal version selection algorithm) is colored green. Other nodes, which aren't in the final build list, are colored grey. — official Go team
go mod graph | modgraphviz | dot -Tsvg -o mod-graph.svg
Requirements
https://graphviz.org/download/
go install golang.org/x/exp/cmd/modgraphviz@latest
Render in browser Go module graphs. Built with D3.js, Javascript, HTTP server in Go. — @PaulXu-cn
go mod graph | gmchart
Requirements
go install github.com/PaulXu-cn/go-mod-graph-chart/gmchart@latest
⏫ Make graph of upstream packages with import-graph
Find unexpected dependencies or visualize project. Works best for small number of packages, for large projects use grep to narrow down subgraph. Without -deps only for current module. — @nikolaydubina
go list -deps -json ./... | jq -c 'select(.Standard!=true) | {from: .ImportPath, to: .Imports[]}' | jsonl-graph | dot -Tsvg > package-graph.svg
Requirements
https://stedolan.github.io/jq/download/
https://graphviz.org/download/
go install github.com/nikolaydubina/import-graph@latest
go install github.com/nikolaydubina/jsonl-graph@latest
⏫ Scrape details about upstream modules and make graph with import-graph
Find low quality or unmaintained dependencies. — @nikolaydubina
go mod graph | import-graph -i=gomod | jsonl-graph -color-scheme=file://$PWD/basic.json | dot -Tsvg > output.svg
Requirements
https://graphviz.org/download/
go install github.com/nikolaydubina/import-graph@latest
go install github.com/nikolaydubina/jsonl-graph@latest
⏫ Scrape licenses of upstream dependencies with go-licenses
Collect all the licenses for checking if you can use the project, for example in proprietary or commercial environment. — Google
go-licenses csv github.com/gohugoio/hugo
Example
github.com/cli/safeexec,https://github.com/cli/safeexec/blob/master/LICENSE,BSD-2-Clause
github.com/bep/tmc,https://github.com/bep/tmc/blob/master/LICENSE,MIT
github.com/aws/aws-sdk-go,https://github.com/aws/aws-sdk-go/blob/master/LICENSE.txt,Apache-2.0
github.com/jmespath/go-jmespath,https://github.com/jmespath/go-jmespath/blob/master/LICENSE,Apache-2.0
github.com/gorilla/websocket,https://github.com/gorilla/websocket/blob/master/LICENSE,BSD-2-Clause
github.com/pelletier/go-toml/v2,https://github.com/pelletier/go-toml/blob/master/v2/LICENSE,MIT
github.com/spf13/cobra,https://github.com/spf13/cobra/blob/master/LICENSE.txt,Apache-2.0
github.com/kyokomi/emoji/v2,https://github.com/kyokomi/emoji/blob/master/v2/LICENSE,MIT
go.opencensus.io,Unknown,Apache-2.0
github.com/Azure/azure-storage-blob-go/azblob,https://github.com/Azure/azure-storage-blob-go/blob/master/azblob/LICENSE,MIT
github.com/yuin/goldmark-highlighting,https://github.com/yuin/goldmark-highlighting/blob/master/LICENSE,MIT
Requirements
go install github.com/google/go-licenses@latest
This tool has extensive syntax for filtering dependencies graphs. It can work with packages and modules. — Egon Elbre
goda graph . | dot -Tsvg -o graph.svg
goda graph -cluster -short "github.com/nikolaydubina/go-cover-treemap:all" | dot -Tsvg -o graph.svg
Requirements
https://graphviz.org/download/
go install github.com/loov/goda@latest
Useful in large refactorings, dependency breaking, physical layout changes. — Alan Donovan, official Go team
Requirements
go install github.com/adonovan/spaghetti@latest
⏫ Use go mod directives
Tell Go compiler which versions of upstreams to include in your build. Tell all users of your module how to deal with versions of your module.
// Deprecated: use example.com/mod/v2 instead.
module example.com/mod
go 1.16
require example.com/other/thing v1.0.2
require example.com/new/thing/v2 v2.3.4
exclude example.com/old/thing v1.2.3
replace example.com/bad/thing v1.4.5 => example.com/good/thing v1.4.5
retract [v1.9.0, v1.9.5]
⏫ Enforce Go code architecture with go-arch-lint
Architecture linter. Will check all project import path and compare with arch rules defined in yml file. Useful for hexagonal / onion / ddd / mvc / etc patterns. — @fe3dback
go-arch-lint
Requirements
go install github.com/fe3dback/go-arch-lint@latest
⏫ Make C4 diagram with go-structurizr
This library provides tools to generate C4 diagrams. The process is a bit involved, however you get diagram generated from real Go code automatically. Steps are outlined in blog. — @krzysztofreczek
Requirements
manually defining Go main.go script to invoke library
graphviz
manual coloring spec (DB, calsses)
Visualize complex or new project quickly or to study project. Requires main.go in module. Supports Graphviz output format. Has many options for filtering and formatting. — official Go team
callgraph -format graphviz . | dot -Tsvg -o graph.svg
recommend: grep <package/class/func of interest>
recommend: grep -v Error since many packages report error
recommend: adding `rankdir=LR;` to graphviz file for denser graph
recommend: you would have to manually fix graphviz file first and last line
Requirements
go install golang.org/x/tools/cmd/callgraph@latest
⏫ Make graph of function calls in package with go-callvis
Quickly track which packages current package is calling and why. — @ofabry
go-callvis .
Requirements
go install github.com/ofabry/go-callvis
⏫ Make PlantUML diagram with goplantuml
Generates class diagram in widely used format with the information on structs, interfaces and their relationships. Render .puml files in for example planttext.com. — @jfeliu007
goplantuml -recursive path/to/gofiles path/to/gofiles2
Requirements
go get github.com/jfeliu007/goplantuml/parser
go install github.com/jfeliu007/goplantuml/cmd/goplantuml@latest
⏫ Make PlantUML diagram with go-plantuml
Automatically generate visualization of classes and interfaces for go packages. Recommend recursive option. Render .puml files in for example planttext.com. — @bykof
go-plantuml generate -d . -r -o graph.puml
Requirements
go install github.com/bykof/go-plantuml@latest
Fresh artistic perspective on Go codebase. GoCity is an implementation of the Code City metaphor for visualizing source code - folders are districts; files are buildings; structs are buildings on the top of their files. This project has research paper "GoCity Code City for Go" at SANER'19. Also available at go-city.github.io. — @rodrigo-brito
Requirements
go install github.com/rodrigo-brito/gocity@latest
⏫ Make histogram of Go files per package
Find when package is too big or too small. Adjust histogram length to maximum value.
go list -json ./... | jq -rc '[.ImportPath, (.GoFiles | length | tostring)] | join(" ")' | perl -lane 'print (" " x (20 - $F[1]), "=" x $F[1], " ", $F[1], "\t", $F[0])'
Example
================== 18 github.com/gin-gonic/gin
============= 13 github.com/gin-gonic/gin/binding
= 1 github.com/gin-gonic/gin/internal/bytesconv
= 1 github.com/gin-gonic/gin/internal/json
=========== 11 github.com/gin-gonic/gin/render
Requirements
https://stedolan.github.io/jq/download/
Explore Go source code in browser. It provides exported symbols summary for navigation. It answers questions like: definition; callers; implementers. It is browser frontend based on go-guru, which was developed by Go core team from Google. — @fzipp
pythia net/http
Requirements
go install github.com/fzipp/pythia@latest
go install golang.org/x/tools/cmd/guru@latest
⏫ 🏚️ Interactively visualize packages with goexplorer
Based on go-callvis, this tool is an interactive package explorer of packages. This tool have not been updated for a long time. — @ofabry
⏫ Make D2 graph of architecture and dependencies with go-arch-lint graph
Can include vendors or not, and be of type 'flow' or 'di'. — @fe3dback
go-arch-lint graph
Requirements
go install github.com/fe3dback/go-arch-lint@latest
⏫ Run go:generate in parallel
Official Go team encourages to run sequentially. However, in certain situations, such as lots of mocks, parallelization helps a lot, albeit, you should consider including your generated files in git. The solution bellow spawns multiple processes, each per pkg.
grep -rnw "go:generate" -E -l "${1:-*.go}" . | xargs -L1 dirname | sort -u | xargs -P 8 -I{} go generate {}
⏫ Generate String method for enum types
This is an official tool for generating String for enums. It supports overrides via comments. — official Go team
package painkiller
//go:generate stringer -type=Pill -linecomment
type Pill int
const (
Placebo Pill = iota
Ibuprofen
Paracetamol
PillAspirin // Aspirin
Acetaminophen = Paracetamol
)
// "Acetaminophen"
var s string = Acetaminophen.String()Requirements
go install golang.org/x/tools/cmd/stringer@latest
⏫ Generate enums encoding with go-enum-encoding
Generate encoding code for enums. This follows json struct tag notation. — @nikolaydubina
go generate ./...
type Color struct{ c uint }
//go:generate go-enum-encoding -type=Color
var (
Undefined = Color{} // json:"-"
Red = Color{1} // json:"red"
Green = Color{2} // json:"green"
Blue = Color{3} // json:"blue"
)Requirements
go install github.com/nikolaydubina/go-enum-encoding@latest
Genereate strict and fast enums. Generated code is much more tightly typed than just iota defined enums. You will get JSON decoder and encoder as well. This tool allows to generate extra fields and default values in enum structs. — @zarldev
goenums <file-with-iota.go>
package milkyway
type planet int // Gravity[float64],RadiusKm[float64],MassKg[float64],OrbitKm[float64],OrbitDays[float64],SurfacePressureBars[float64],Moons[int],Rings[bool]
//go:generate goenums planets.go
const (
unknown planet = iota // invalid
mercury // Mercury 0.378,2439.7,3.3e23,57910000,88,0.0000000001,0,false
venus // Venus 0.907,6051.8,4.87e24,108200000,225,92,0,false
earth // Earth 1,6378.1,5.97e24,149600000,365,1,1,false
mars // Mars 0.377,3389.5,6.42e23,227900000,687,0.01,2,false
jupiter // Jupiter 2.36,69911,1.90e27,778600000,4333,20,4,true
saturn // Saturn 0.916,58232,5.68e26,1433500000,10759,1,7,true
uranus // Uranus 0.889,25362,8.68e25,2872500000,30687,1.3,13,true
neptune // Neptune 1.12,24622,1.02e26,4495100000,60190,1.5,2,true
)Requirements
go install github.com/zarldev/goenums@latest
⏫ 🔥 Generate data types from JSON Schema with go-jsonschema
JSON Schema is widely used standard for definition of structured data types. This tool will generate Go struct, decoder and validation based on JSON Schema spec. — @omissis
go-jsonschema -p main myschema.jsonschema
// Code generated by github.com/atombender/go-jsonschema, DO NOT EDIT.
package main
import "encoding/json"
import "fmt"
type Veggie struct {
// Do I like this vegetable?
VeggieLike bool `json:"veggieLike" yaml:"veggieLike" mapstructure:"veggieLike"`
// The name of the vegetable.
VeggieName string `json:"veggieName" yaml:"veggieName" mapstructure:"veggieName"`
}
// UnmarshalJSON implements json.Unmarshaler.
func (j *Veggie) UnmarshalJSON(b []byte) error {
var raw map[string]interface{}
if err := json.Unmarshal(b, &raw); err != nil {
return err
}
if v, ok := raw["veggieLike"]; !ok || v == nil {
return fmt.Errorf("field veggieLike in Veggie: required")
}
if v, ok := raw["veggieName"]; !ok || v == nil {
return fmt.Errorf("field veggieName in Veggie: required")
}
type Plain Veggie
var plain Plain
if err := json.Unmarshal(b, &plain); err != nil {
return err
}
*j = Veggie(plain)
return nil
}
// A representation of a person, company, organization, or place
type A2Schema struct {
// Fruits corresponds to the JSON schema field "fruits".
Fruits []string `json:"fruits,omitempty" yaml:"fruits,omitempty" mapstructure:"fruits,omitempty"`
// Vegetables corresponds to the JSON schema field "vegetables".
Vegetables []Veggie `json:"vegetables,omitempty" yaml:"vegetables,omitempty" mapstructure:"vegetables,omitempty"`
}Example
{
"$id": "https://example.com/arrays.schema.json",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"description": "A representation of a person, company, organization, or place",
"type": "object",
"properties": {
"fruits": {
"type": "array",
"items": {
"type": "string"
}
},
"vegetables": {
"type": "array",
"items": {
"$ref": "#/$defs/veggie"
}
}
},
"$defs": {
"veggie": {
"type": "object",
"required": [
"veggieName",
"veggieLike"
],
"properties": {
"veggieName": {
"type": "string",
"description": "The name of the vegetable."
},
"veggieLike": {
"type": "boolean",
"description": "Do I like this vegetable?"
}
}
}
}
}
Requirements
go get github.com/atombender/go-jsonschema/...
go install github.com/atombender/go-jsonschema@latest
⏫ 🔥 Generate constructor for a struct with gonstructor
Constructor is a widely used useful pattern. This tool generates basic version of it that passes arguments to struct. It also supports intializer method. — @moznion
//go:generate gonstructor --type=Structure --constructorTypes=allArgs
type Structure struct {
foo string
bar io.Reader
Buz chan interface{}
}Requirements
go install golang.org/x/tools/cmd/goimports@latest
go install github.com/moznion/gonstructor/cmd/gonstructor@latest
This tool generates basic test placeholder. It is included into official Go plugin in VSCode and other major code editors. — @cweill
This mocking framework integrates well with Go testing package. — Go Core team
mockgen . Conn,Driver
# foo.go
type Foo interface {
Bar(x int) int
}
func SUT(f Foo) {
// ...
}
# foo_test.go
func TestFoo(t *testing.T) {
ctrl := gomock.NewController(t)
defer ctrl.Finish()
m := NewMockFoo(ctrl)
// Does not make any assertions. Executes the anonymous functions and returns
// its result when Bar is invoked with 99.
m.
EXPECT().
Bar(gomock.Eq(99)).
DoAndReturn(func(_ int) int {
time.Sleep(1*time.Second)
return 101
}).
AnyTimes()
// Does not make any assertions. Returns 103 when Bar is invoked with 101.
m.
EXPECT().
Bar(gomock.Eq(101)).
Return(103).
AnyTimes()
SUT(m)
}Requirements
go install github.com/golang/mock/mockgen@v1.6.0
⏫ Generate interface for a struct with ifacemaker
This is a development helper program that generates a Golang interface by inspecting the structure methods of an existing .go file. The primary use case is to generate interfaces for gomock, so that gomock can generate mocks from those interfaces. This makes unit testing easier. — @vburenin
ifacemaker -f human.go -s Human -i HumanIface -p humantest -y "HumanIface makes human interaction easy" -c "DONT EDIT: Auto generated"
# human.go
package main
import "fmt"
type Human struct {
name string
age int
}
// Returns the name of our Human.
func (h *Human) GetName() string {
return h.name
}
// Our Human just had a birthday! Increase its age.
func (h *Human) Birthday() {
h.age += 1
fmt.Printf("I am now %d years old!\n", h.age)
}
// Make the Human say hello.
func (h *Human) SayHello() {
fmt.Printf("Hello, my name is %s, and I am %d years old.\n", h.name, h.age)
}
func main() {
human := &Human{name: "Bob", age: 30}
human.GetName()
human.SayHello()
human.Birthday()
}
# human_interface.go
// DONT EDIT: Auto generated
package humantest
// HumanIface makes human interaction easy
type HumanIface interface {
// Returns the name of our Human.
GetName() string
// Our Human just had a birthday! Increase its age.
Birthday()
// Make the Human say hello.
SayHello()
}Requirements
go install github.com/vburenin/ifacemaker@latest
⏫ Generate interface for a struct with interfacer
This tool generates interface for a struct. Can be invoked in go:generate. — @rjeczalik
interfacer -for os.File -as mock.File
// Created by interfacer; DO NOT EDIT
package mock
import (
"os"
)
// File is an interface generated for "os".File.
type File interface {
Chdir() error
Chmod(os.FileMode) error
Chown(int, int) error
Close() error
Fd() uintptr
Name() string
Read([]byte) (int, error)
ReadAt([]byte, int64) (int, error)
Readdir(int) ([]os.FileInfo, error)
Readdirnames(int) ([]string, error)
Seek(int64, int) (int64, error)
Stat() (os.FileInfo, error)
Sync() error
Truncate(int64) error
Write([]byte) (int, error)
WriteAt([]byte, int64) (int, error)
WriteString(string) (int, error)
}⏫ Generate interface for a struct with struct2interface
This is alternative tool for interface generation that is aimed to be faster and leaner. It generates only pointer method receiver methods for a struct. — @reflog
struct2interface -f . -i IDecimal -p fpdecimal -s Decimal -o idecimal.go
Requirements
go install github.com/reflog/struct2interface@latest
This tool generates struct that can read and write CSV file of this struct. Order of fields is hardcoded. — @rjeczalik
structer -f aws-billing.csv -tag json -as billing.Record
# aws-billing.csv
# "InvoiceID","PayerAccountId","LinkedAccountId","RecordType","RecordID","BillingPeriodStartDate","BillingPeriodEndDate","InvoiceDate"
# "Estimated","123456","","PayerLineItem","5433212345","2016/01/01 00:00:00","2016/01/31 23:59:59","2016/01/21 19:19:06"
# record.go
// Record is a struct generated from "aws-billing.csv" file.
type Record struct {
InvoiceID string `json:"invoiceID"`
PayerAccountID int64 `json:"payerAccountID"`
LinkedAccountID string `json:"linkedAccountID"`
RecordType string `json:"recordType"`
RecordID int64 `json:"recordID"`
BillingPeriodStartDate time.Time `json:"billingPeriodStartDate"`
BillingPeriodEndDate time.Time `json:"billingPeriodEndDate"`
InvoiceDate time.Time `json:"invoiceDate"`
}
// MarshalCSV encodes r as a single CSV record.
func (r *Record) MarshalCSV() ([]string, error) {
...
}
// UnmarshalCSV decodes a single CSV record into r.
func (r *Record) UnmarshalCSV(record []string) error {
...
}⏫ Modify struct field tags with gomodifytags
This tool makes it easy to update, add or delete the tags and options in a struct field. You can add new tags, update existing tags (such as appending a new key, i.e: db, xml, etc..) or remove existing tags. It's intended to be used by an editor, but also has modes to run it from the terminal. — @fatih
Requirements
go install github.com/fatih/gomodifytags@latest
⏫ Generate code from OpenAPI 3 specification with oapi-codegen
Generate Go client and server boilerplate from OpenAPI 3 specifications. — @deepmap
oapi-codegen --config=config.yaml api.yaml
Requirements
go install github.com/deepmap/oapi-codegen/v2/cmd/oapi-codegen@latest
⏫ Replace symbol with gofmt
I found this in announcement notice of Go 1.18 for changes to interface{} to any. This can be useful for other refactorings too.
gofmt -w -r 'interface{} -> any' .
With this tool it is very easy to perform refactorings. It is also possible to organize and maintan your refactoring procedures through patches. — Uber
@@
@@
-import "errors"
-errors.New(fmt.Sprintf(...))
+fmt.Errorf(...)Example
return errors.New(fmt.Sprintf("invalid port: %v", err))
// becomes
return fmt.Errorf("invalid port: %v", err)
This is official tool for for grouping and sorting imports. However, it has only basic grouping functionality. — Go Core team
goimports -w -local .
Requirements
go install golang.org/x/tools/cmd/goimports@latest
This tool splits all import blocks into different sections, now support five section types: standard (e.g. 'fmt'); custom; default; blank; dot. It will keep each section sorted and keep ordering of sections consistent. — @daixiang0
gci write -s standard -s default -s "prefix(github.com/daixiang0/gci)" main.go
// before
package main
import (
"golang.org/x/tools"
"fmt"
"github.com/daixiang0/gci"
)
// after
package main
import (
"fmt"
"golang.org/x/tools"
"github.com/daixiang0/gci"
)Requirements
go install github.com/daixiang0/gci@latest
This tool groups and sorts imports within groups. It keeps consitent ordering of groups. Detection of groups may be not always accurate. — @anqiansong
goimportx --file /path/to/file.go --group "system,local,third"
package main
import (
"flag"
"io"
"log"
"os"
"github.com/nikolaydubina/mdpage/page"
"github.com/nikolaydubina/mdpage/render"
yaml "gopkg.in/yaml.v3"
)Requirements
go install github.com/anqiansong/goimportx@latest
You may want to do this as preparation for other refactoring steps. This tool has good emacs integration, otherwise may it be hard to use. — @dominikh
# before
myFunc(T{1, 2, 3})
# after
myFunc(T{A: 1, B: 2, C: 3})Requirements
go install honnef.co/go/tools/cmd/keyify@2022.1
Return trace is the path that error took to return to user. This can be more illustrative than typical stack trace that procuded the error. This tool have conenienve automatic instrumentation CLI to update your code. — @bracesdev
git ls-files -- '*.go' | xargs errtrace -w
Requirements
use packae "braces.dev/errtrace"
instrument code by wrapping errors through all functions with this library
This library collects stack traces and pretty prints code fragments. Stack traces induce performance penalty. — @ztrue
package main
import (
"io/ioutil"
"github.com/ztrue/tracerr"
)
func main() {
if err := read(); err != nil {
tracerr.PrintSourceColor(err)
}
}
func read() error {
return readNonExistent()
}
func readNonExistent() error {
_, err := ioutil.ReadFile("/tmp/non_existent_file")
// Add stack trace to existing error, no matter if it's nil.
return tracerr.Wrap(err)
}⏫ Pretty print panic messages with panicparse
Read panic messages easier. Need to redirect STDERR to this tool with panic stack traces. The tool has HTML output and does lots of deduplication and enhancements. Refer to examples in original repo. — @maruel
go test -v |& pp
Requirements
go install github.com/maruel/panicparse/v2/cmd/pp@latest
⏫ Show compiler optimization decisions on heap and inlining
Building with -m flag will show decisions of compiler on inlining and heap escape. This can help you to validate your understanding of your code and optimize it.
go build -gcflags="-m -m" . 2>&1 | grep inline
Example
...
./passengerfp.go:25:6: cannot inline (*PassengerFeatureTransformer).Fit: function too complex: cost 496 exceeds budget 80
...
./passengerfp.go:192:6: can inline (*PassengerFeatureTransformer).NumFeatures with cost 35 as: method(*PassengerFeatureTransformer) func() int { if e == nil { return 0 }; count := 6; count += (*transformers.OneHotEncoder).NumFeatures(e.Sex); count += (*transformers.OneHotEncoder).NumFeatures(e.Embarked); return count }
...
./passengerfp.go:238:43: inlining call to transformers.(*OneHotEncoder).FeatureNames
./passengerfp.go:238:43: inlining call to transformers.(*OneHotEncoder).NumFeatures
...
./passengerfp.go:151:7: parameter e leaks to {heap} with derefs=0:
./passengerfp.go:43:11: make(map[string]uint) escapes to heap
⏫ Disable inlining
Usually you may not need it, but can reduce binary size and even improve performance.
go build -gcflags="-l" .
⏫ Aggressive inlining
Usually you may not need it, but can improve performance. This includes mid-stack inlining.
go build -gcflags="-l -l -l -l" .
⏫ Profile-guided optimization
Starting go 1.20 compiler supports Profile-gudied optimization. You need to collect profiles and then supply in compulation to compiler. You can get improvement in performance by around 4%. Officual guideline.
1. store a `pprof` CPU profile with filename default.pgo in the main package directory of the profiled binary
2. build with `go build -pgo=auto``, which will pick up `default.pgo` files automatically.
⏫ Manually disable or enable cgo
Disable cgo with CGO_ENABLED=0 and enable with CGO_ENABLED=1. If you don't, cgo may end-up being enabled or code dynamically linked if, for example, you use some net or os packages. You may want to disable cgo to improve performance, since complier and runtime would have easier job optimizing code. This also should reduce your image size, as you can have alpine image with less shared libraries.
⏫ Include metadata in binary during compilation with ldflags
You can pass metadata through compiler to your binary. This is useful for including things like git commit, database schema version, integrity hashes. Variables can only be strings.
go build -v -ldflags="-X 'main.Version=v1.0.0'"
go build -v -ldflags="-X 'my/pkg/here.Variable=some-string'"
package main
var Version string
func main() {
// Version here has some value
...
}⏫ Visualise dependencies size in compiled binaries with go-size-analyzer
A tool for analyzing the dependencies in compiled Golang binaries, providing insight into their impact on the final build. WebAssembly demo: https://gsa.zxilly.dev. — @Zxilly
gsa --web target_binary
Requirements
go install github.com/Zxilly/go-size-analyzer/cmd/gsa@latest
⏫ Make treemap breakdown of Go executable binary with go-binsize-treemap
Useful for studying Go compiler, large projects, projects with C/C++ and cgo, 3rd party dependencies, embedding. However, total size may not be something to worry about for your executable. — @nikolaydubina
go tool nm -size <binary finename> | go-binsize-treemap > binsize.svg
Requirements
go install github.com/nikolaydubina/go-binsize-treemap@latest
⏫ Custom import path
Go can automatically fetch from custom http/https servers using <meta> tag to discover how to fetch code. There are multiple tools that can help set this up. This can help for security and analytics. This is also known as vanity URLs. documentation.
# some notable examples
golang.org/x/exp
go.uber.org/multierr
honnef.co/go/tools/cmd/staticcheck
⏫ Custom import path with govanityurls
Simple HTTP server that lets you host custom import paths for your Go packages. — Google
govanityurls
Requirements
go install github.com/GoogleCloudPlatform/govanityurls@latest
Simple HTTP server that lets you host custom import paths for your Go packages. — Uber
sally
Requirements
go install go.uber.org/sally@latest
⏫ Custom import path with kkn.fi/vanity
Simple HTTP server that lets you host custom import paths for your Go packages. — @kare
vanity
Requirements
go get kkn.fi/vanity
⏫ Custom import path enforcement
When import path is using custom domain, it is possible to block code from compilation unless it is used. This can help ensure security and prevent breaking changes. documentation.
package pdf // import "rsc.io/pdf"This tool makes it easier for managing multiple Go versions on same host. This works through intercepting Go commands and directing them to the right Go version bin and directory. Official Go documentation on this topic. — @clivern
⏫ Get assembly of Go code snippets online
Use godbolt.org to compile and see assembly of short Go code. You can check different platforms and compilers including cgo. This tool is commonly used by C++ community. — @mattgodbolt
⏫ Get Go SSA intermediary representation with ssaplayground
Check what does Go compiler do. Might be useful if you trying to optimize some code or learn more about compiler. https://golang.design/gossa. — @changkun
Understand how Go is compiled better. — @egonelbre
Requirements
go install loov.dev/lensm@main
⏫ 🔥 View Go assembly with color annotation with pat/disfunc
This tool shows assmebly of functions and what lines mean by color. — @maruel
disfunc -f 'nin\.CanonicalizePath$' -pkg ./cmd/nin | less -R
Requirements
go install github.com/maruel/pat/cmd/...@latest
Write better quality Go assembly quicker in Go language itself. This tool conveniently generates stub for Go code to call your generated assembly. Used by Go core. — @mmcloughlin
//go:build ignore
// +build ignore
package main
import . "github.com/mmcloughlin/avo/build"
func main() {
TEXT("Add", NOSPLIT, "func(x, y uint64) uint64")
Doc("Add adds x and y.")
x := Load(Param("x"), GP64())
y := Load(Param("y"), GP64())
ADDQ(x, y)
Store(y, ReturnIndex(0))
RET()
Generate()
}⏫ Generate AST for code snippets with go/ast
Access Go core AST mechanism to generate AST.
package main
import (
"go/ast"
"go/parser"
"go/token"
)
func main() {
fs := token.NewFileSet()
tr, _ := parser.ParseExpr("(3-1) * 5")
ast.Print(fs, tr)
}Example
0 *ast.BinaryExpr {
1 . X: *ast.ParenExpr {
2 . . Lparen: -
3 . . X: *ast.BinaryExpr {
4 . . . X: *ast.BasicLit {
5 . . . . ValuePos: -
6 . . . . Kind: INT
7 . . . . Value: "3"
8 . . . }
9 . . . OpPos: -
10 . . . Op: -
11 . . . Y: *ast.BasicLit {
12 . . . . ValuePos: -
13 . . . . Kind: INT
14 . . . . Value: "1"
15 . . . }
16 . . }
17 . . Rparen: -
18 . }
19 . OpPos: -
20 . Op: *
21 . Y: *ast.BasicLit {
22 . . ValuePos: -
23 . . Kind: INT
24 . . Value: "5"
25 . }
26 }
This is a wrapper around go/ast machinery that makes generating AST easier. — @reflog
echo "a := 1" | go2ast
Example
[]ast.Stmt {
&ast.AssignStmt {
Lhs: []ast.Expr {
&ast.Ident {
Name: "a",
},
},
Tok: :=,
Rhs: []ast.Expr {
&ast.BasicLit {
ValuePos: 32,
Kind: INT,
Value: "1",
},
},
},
}
Requirements
go install github.com/reflog/go2ast@latest
This tool provides a visual overview of Go SSA function using Graphviz. This is especially useful in SSA-based static analysis. This tool generates an HTML page that is easy to navigate. demo. — @SilverRainZ
go-ssaviz ./...
Requirements
# get graphviz
go install github.com/SilverRainZ/go-ssaviz@latest
This tool visualizes AST as graph, which may be useful to navigate and undertand Go AST. This tool has not been maintaned for a while. — @xiazemin
Requirements
graphviz
This tool can convert C assembly .s into Go assbmely .s files. This is useful for reusing compiler optimizations such as SIMD or loop unrolling in C, which can lead to 10x speedups. However, project has been archieved 4+ years ago. — @fwessels
gcc -O3 -march=native -S -o c_code.s c_code.c
c2goasm -a c_code.s go_c_code.s
go build -o go_c_code.o -gcflags="-S" go_c_code.s
Requirements
go install github.com/minio/c2goasm@latest
Embed interactive Go Playground component into your blog. Hugo, Docusaurus, Ghost are supported. There is also another tool soksan, however it is discontinued. Live demo with guideline. Other resources — GitLab considering to add it in issue; alternative implementation guideline. — @ggicci
## Sample Code
{{% goplay %}}
'''go
package main
func main() {
println("hello world")
}
'''
{{% /goplay %}}
Requirements
reverse proxy server to https://play.golang.org
bloging playform with support for embedding javascript
⏫ Run alternative Go Playground with goplay.tools
Improved Go Playground featuring dark theme, code autocomplete, vim mode, WebAssembly. Available at https://goplay.tools/. — @x1unix
⏫ Run interactive Go kernels in Jupyter Notebook with gophernotes
Run interactive Go interpreter in Jupyter Notebook browser. As of 2023-06-04, it is using gomacro interpreter and can have issues with loading 3rd party pacakges. — @gopherdata
Requirements
# jupyter notebook
go install github.com/gopherdata/gophernotes@v0.7.5
# more instructions on how to install Jupyter Notebook Go kernel in original repo
This interpreter works with 3rd party pacakges located in $GOPATH/src. It can also be triggered within Go programmatically via Eval(). Works everywhere Go works. — @traefik
yaegi
Example
$ yaegi
> import "github.com/nikolaydubina/fpdecimal"
: 0x140000faaf0
> a, _ := fpdecimal.FromString("10.12")
: {0}
> b, _ := fpdecimal.FromString("5.38")
: {0}
> c := a.Add(b)
: {15500}
> c.String()
: 15.500
>
Requirements
go install github.com/traefik/yaegi@latest
This is interactive Go interpreter and debugger with REPL, Eval, generics and Lisp-like macros. You can run functions, import 3rd patry packages. Can be useful for learning and experimentation. Some nice features: autocomplete; constant expressions arithmetics. As of 2023-06-02, issues with importing 3rd paty package are possible. — @cosmos72
gomacro
Example
$ gomacro
gomacro> import "fmt"
gomacro> fmt.Println("hello, world!")
hello, world!
14 // int
<nil> // error
gomacro>
Requirements
go install github.com/cosmos72/gomacro@latest
Run Go one-liners. This tool will print to STDOUT the return of a function call. — @natefinch
cat README.md | gorram crypto/sha1 Sum
echo 12345 | gorram encoding/base64 StdEncoding.EncodeToString
gorram net/http Get https://google.com
Requirements
go install github.com/natefinch/gorram@latest
Run Go functions in shell. You can also pass parameters directly from shell. — @nickwells
gosh -pln '"Hello, World!"'
gosh -pln 'math.Pi'
gosh -n -b 'count := 0' -e 'count++' -a-pln 'count'
gosh -http-handler 'http.FileServer(http.Dir("/tmp/xxx"))'
gosh -n -b-p '"Radius: "' -e 'r, err := strconv.ParseFloat(_l.Text(), 64)' -e-s iferr -pf '"Area: %9.2f
", r*r*math.Pi' -p '"Radius:"'
Requirements
go install github.com/nickwells/utilities/gosh@latest
⏫ Run simple fileserver with net/http
It takes one line to run HTTP file server in Go. Akin to famous oneliner in Python python3 -m http.server and python -m SimpleHTTPServer. Run this file as usually go run <filename>.
package main
import "net/http"
func main() { http.ListenAndServe(":9000", http.FileServer(http.Dir("."))) }Fresh artistic perspective on coroutines execution. There is no advanced functions and it is hard to analyze production systems. However, it could be interesting for educational purposes. — @divan
Requirements
go install github.com/divan/gotrace@latest
patch Go compiler, available via Docker
more instructions in original repo
⏫ Wrap command with os/exec
Orignally posted in blog.
cmd := exec.Command("ls", "/usr/local/bin")
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
return cmd.Run()⏫ Capture output of command to file with os/exec
Orignally posted in blog. — Aaron Son
log, err := os.Create("output.log")
if err != nil {
return err
}
defer log.Close()
cmd := exec.Command("ls", "/usr/local/bin")
cmd.Stdout = log
cmd.Stderr = log
return cmd.Run()⏫ Capture output of command and process it with os/exec
Orignally posted in blog. — Aaron Son
cmd := exec.Command("ls", "/usr/local/bin")
stdout, err := cmd.StdoutPipe()
if err != nil {
return err
}
scanner := bufio.NewScanner(stdout)
err = cmd.Start()
if err != nil {
return err
}
for scanner.Scan() {
// Do something with the line here.
ProcessLine(scanner.Text())
}
if scanner.Err() != nil {
cmd.Process.Kill()
cmd.Wait()
return scanner.Err()
}
return cmd.Wait()⏫ Piping between processes with os/exec
ls /usr/local/bin | grep pip. Orignally posted in blog. — Aaron Son
r, w, err := os.Pipe()
if err != nil {
return err
}
defer r.Close()
ls := exec.Command("ls", "/usr/local/bin")
ls.Stdout = w
err = ls.Start()
if err != nil {
return err
}
defer ls.Wait()
w.Close()
grep := exec.Command("grep", "pip")
grep.Stdin = r
grep.Stdout = os.Stdout
return grep.Run()⏫ errgroup and CommandContext with os/exec
Orignally posted in blog. — Aaron Son
eg, ctx := errgroup.WithContext(context.Background())
sleeps := make([]*exec.Cmd, 3)
sleeps[0] = exec.CommandContext(ctx, "sleep", "100")
sleeps[1] = exec.CommandContext(ctx, "sleep", "100")
sleeps[2] = exec.CommandContext(ctx, "sleep", "notanumber")
for _, s := range sleeps {
s := s
eg.Do(func() error {
return s.Run()
})
}
return eg.Wait()Command line monitoring for goroutines. — @bcicen
grmon
Requirements
# start pprof server or grmon in your Go process
go install github.com/bcicen/grmon@latest
Monitoring memory of Go processes, forcing GC, getting version of Go of processes. — Google
gops
Example
983 980 uplink-soecks go1.9 /usr/local/bin/uplink-soecks
52697 52695 gops go1.10 /Users/jbd/bin/gops
4132 4130 foops * go1.9 /Users/jbd/bin/foops
51130 51128 gocode go1.9.2 /Users/jbd/bin/gocode
Requirements
go install github.com/google/gops@latest
This tool exposes HTTP endpoint with charts for Go runtime such as heap, objects, goroutines, GC pauses, scheduler. This is useful drop-in solution for visualization of Go runtime. — @arl
Requirements
go get github.com/arl/statsviz@latest
⏫ Auto-Instrument all functions with go-instrument
Automatically instrument all functions with Open Telemetry Spans by code generation. Inserts errors into Spans. — @nikolaydubina
find . -name "*.go" | xargs -I{} go-instrument -app my-service -w -filename {}
Requirements
go install github.com/nikolaydubina/go-instrument@latest
Automatically instrument all functions with Open Telemetry Spans by code generation. Inserts errors into Spans. Supports custom templates and can be used for Open Tracing or any custom insertions. — @hedhyw
otelinji -w -filename input_file.go
otelinji -filename input_file.go > input_file.go
find . -name "*.go" | grep -v "vendor/\|.git/\|_test.go" | xargs -n 1 -t otelinji -w -filename
Requirements
go install github.com/hedhyw/otelinji/cmd/otelinji@latest
⏫ 🔥 Auto-Instrument functions for DataDog with orchestrion
This is official Datadog tool for automatic instrumentation of code. It has very convenient compiler directives for instrumentation. — @DataDog
orchestrion -w ./
//dd:span my:tag
func GetSomeData(ctx context.Context) ([]byte, error) {
...Requirements
go install github.com/datadog/orchestrion@latest
This tool allows to injest profiling data from your application. You would need to add integration in your main file that will sample in-process data and send it to Pyroscope. Here are useful resources blog-go-memory-leaks. — Grafana Labs
⏫ Run benchmarks
Start here. This is the standard tool for benchmarking. It can also do advanced features like mutex profiles. More flags are in Go documentation and go help testflag.
go test -bench=. -benchmem -benchtime=10s ./...
Example
goos: darwin
goarch: arm64
pkg: github.com/nikolaydubina/fpmoney
BenchmarkArithmetic/add_x1-10 1000000000 0.5 ns/op 0 B/op 0 allocs/op
BenchmarkArithmetic/add_x100-10 18430124 64.6 ns/op 0 B/op 0 allocs/op
BenchmarkJSONUnmarshal/small-10 3531835 340.7 ns/op 198 B/op 3 allocs/op
BenchmarkJSONUnmarshal/large-10 2791712 426.9 ns/op 216 B/op 3 allocs/op
BenchmarkJSONMarshal/small-10 4379685 274.4 ns/op 144 B/op 4 allocs/op
BenchmarkJSONMarshal/large-10 3321205 345.8 ns/op 192 B/op 5 allocs/op
PASS
ok github.com/nikolaydubina/fpmoney 62.744s
⏫ Table-driven benchmarks
Similar to tests, Go supports table-driven benchmarks, which is very helpful for fine gradation of meta-parameters. More details in the Go blog.
func benchIteratorSelector(b *testing.B, n int) {
// ... setup here
b.ResetTimer()
for n := 0; n < b.N; n++ {
err := myExpensiveFunc()
if err != nil {
b.Error(err)
}
}
}
func BenchmarkIteratorSelector(b *testing.B) {
for _, q := range []int{100, 1000, 10000, 100000} {
b.Run(fmt.Sprintf("n=%d", q), func(b *testing.B) {
benchIteratorSelector(b, q)
})
}
}
Example
BenchmarkIteratorSelector/n=100-10 297792 4265 ns/op 5400 B/op 13 allocs/op
BenchmarkIteratorSelector/n=1000-10 31400 38182 ns/op 9752 B/op 16 allocs/op
BenchmarkIteratorSelector/n=10000-10 3134 380777 ns/op 89112 B/op 24 allocs/op
BenchmarkIteratorSelector/n=100000-10 310 3827292 ns/op 912410 B/op 32 allocs/op
⏫ Generate benchmak CPU and Memory profiles with go test
This is useful for identifying most time or memory consuming parts. Recommended to run for single benchmark at a time and with -count or -benchtime for better accuracy.
go test -bench=<my-benchmark-name> -cpuprofile cpu.out -memprofile mem.out ./...
⏫ Visualize callgraph of profiles with pprof
Once you generate profiles, visualize them with pprof. Both memory and CPU profiles are supported. Many options are available. Refer to the link you get in SVG to how to interpret this graph. More official documentation blog, pkg-doc. — official Go team
go tool pprof -svg cpu.out > cpu.svg
go tool pprof -svg mem.out > mem.svg
⏫ Visualize flamegraphs of profiles with pprof
Latest versions of pprof can also render Flamegraphs for profiles. Make sure you set -http to start webserver. Then it is available in "View > Graph" in at http://0.0.0.0:80. — Google
pprof -http=0.0.0.0:80 cpu.out
Requirements
go install github.com/google/pprof@latest
⏫ Visualize profiles online
You can also visualize profiles with online tools are aloso available https://www.speedscope.app (cpu).
This is standard way to compare two benchmark outputs. Names of benchmarks should be the same. Generate benchmarks as per usual. You would get multiple tables per dimension. If no output, then pass -split="XYZ". If you do not see delta, then pass -count=2 or more in benchmark generation. It is recommended to have alternative implementations in different packages, to keep benchmark names the same. — official Go team
benchstat -split="XYZ" old.txt new.txt
Example
name old time/op new time/op delta
JSONUnmarshal/small-10 502ns ± 0% 331ns ± 0% -33.99% (p=0.008 n=5+5)
JSONUnmarshal/large-10 572ns ± 0% 414ns ± 0% -27.64% (p=0.008 n=5+5)
JSONMarshal/small-10 189ns ± 0% 273ns ± 0% +44.20% (p=0.008 n=5+5)
JSONMarshal/large-10 176ns ± 0% 340ns ± 0% +93.29% (p=0.008 n=5+5)
name old alloc/op new alloc/op delta
JSONUnmarshal/small-10 271B ± 0% 198B ± 0% -26.94% (p=0.008 n=5+5)
JSONUnmarshal/large-10 312B ± 0% 216B ± 0% -30.77% (p=0.008 n=5+5)
JSONMarshal/small-10 66.0B ± 0% 144.0B ± 0% +118.18% (p=0.008 n=5+5)
JSONMarshal/large-10 72.0B ± 0% 192.0B ± 0% +166.67% (p=0.008 n=5+5)
name old allocs/op new allocs/op delta
JSONUnmarshal/small-10 6.00 ± 0% 3.00 ± 0% -50.00% (p=0.008 n=5+5)
JSONUnmarshal/large-10 7.00 ± 0% 3.00 ± 0% -57.14% (p=0.008 n=5+5)
JSONMarshal/small-10 2.00 ± 0% 4.00 ± 0% +100.00% (p=0.008 n=5+5)
JSONMarshal/large-10 2.00 ± 0% 5.00 ± 0% +150.00% (p=0.008 n=5+5)
Requirements
go install golang.org/x/perf/cmd/benchstat@latest
Compare multiple benchmarks. Names of benchmarks should be the same. Generate benchmarks as per usual. You would get multiple tables per dimension. If no output, then pass -split="XYZ". It is recommended to have alternative implementations in different packages, to keep benchmark names the same. — official Go team
benchstat -split="XYZ" int.txt float32.txt fpmoney.txt
Example
name \ time/op int.bench float32.bench fpmoney.bench
JSONUnmarshal/small-10 481ns ± 2% 502ns ± 0% 331ns ± 0%
JSONUnmarshal/large-10 530ns ± 1% 572ns ± 0% 414ns ± 0%
JSONMarshal/small-10 140ns ± 1% 189ns ± 0% 273ns ± 0%
JSONMarshal/large-10 145ns ± 0% 176ns ± 0% 340ns ± 0%
name \ alloc/op int.bench float32.bench fpmoney.bench
JSONUnmarshal/small-10 269B ± 0% 271B ± 0% 198B ± 0%
JSONUnmarshal/large-10 288B ± 0% 312B ± 0% 216B ± 0%
JSONMarshal/small-10 57.0B ± 0% 66.0B ± 0% 144.0B ± 0%
JSONMarshal/large-10 72.0B ± 0% 72.0B ± 0% 192.0B ± 0%
name \ allocs/op int.bench float32.bench fpmoney.bench
JSONUnmarshal/small-10 6.00 ± 0% 6.00 ± 0% 3.00 ± 0%
JSONUnmarshal/large-10 7.00 ± 0% 7.00 ± 0% 3.00 ± 0%
JSONMarshal/small-10 2.00 ± 0% 2.00 ± 0% 4.00 ± 0%
JSONMarshal/large-10 2.00 ± 0% 2.00 ± 0% 5.00 ± 0%
Requirements
go install golang.org/x/perf/cmd/benchstat@latest
This tool runs benchmarks and shows delta between git commits. It can also be useful in GitHub Actions. — @maruel
Example
$ ba -against HEAD~1
warming up
go test -bench . -benchtime 100ms -count 1 -run ^$ -cpu 1 ./...
git checkout HEAD~1
go test -bench . -benchtime 100ms -count 1 -run ^$ -cpu 1 ./...
git checkout 02152d698f7d548c
02152d698f7d548c...HEAD~1 (1 commits), 100ms x 2 times/batch, batch repeated 3 times.
go test -bench . -benchtime 100ms -count 2 -run ^$ -cpu 1 ./...
git checkout HEAD~1
go test -bench . -benchtime 100ms -count 2 -run ^$ -cpu 1 ./...
git checkout 02152d698f7d548c
go test -bench . -benchtime 100ms -count 2 -run ^$ -cpu 1 ./...
git checkout HEAD~1
go test -bench . -benchtime 100ms -count 2 -run ^$ -cpu 1 ./...
git checkout 02152d698f7d548c
go test -bench . -benchtime 100ms -count 2 -run ^$ -cpu 1 ./...
git checkout HEAD~1
go test -bench . -benchtime 100ms -count 2 -run ^$ -cpu 1 ./...
git checkout 02152d698f7d548c
name old time/op new time/op delta
HashCommand 69.0ns ± 2% 67.7ns ± 2% -1.91% (p=0.041 n=6+6)
CLParser 281µs ± 1% 281µs ± 1% ~ (p=0.699 n=6+6)
LoadManifest 437ms ± 7% 430ms ± 3% ~ (p=0.937 n=6+6)
CanonicalizePathBits 85.9ns ± 1% 86.2ns ± 0% ~ (p=1.000 n=6+6)
CanonicalizePath 83.9ns ± 1% 84.6ns ± 0% ~ (p=0.058 n=6+6)
name old alloc/op new alloc/op delta
HashCommand 0.00B 0.00B ~ (all equal)
CLParser 164kB ± 0% 164kB ± 0% ~ (all equal)
LoadManifest 298MB ± 0% 295MB ± 0% -0.78% (p=0.002 n=6+6)
CanonicalizePathBits 80.0B ± 0% 80.0B ± 0% ~ (all equal)
CanonicalizePath 80.0B ± 0% 80.0B ± 0% ~ (all equal)
name old allocs/op new allocs/op delta
HashCommand 0.00 0.00 ~ (all equal)
CLParser 1.64k ± 0% 1.64k ± 0% ~ (all equal)
LoadManifest 2.61M ± 0% 2.57M ± 0% -1.71% (p=0.002 n=6+6)
CanonicalizePathBits 1.00 ± 0% 1.00 ± 0% ~ (all equal)
CanonicalizePath 1.00 ± 0% 1.00 ± 0% ~ (all equal)
Requirements
go install github.com/maruel/pat/cmd/...@latest
⏫ Continuous benchmarking
Track how benchmarks change in codebase over time. This is accomplished by running benchmarks for git commits, storing results, and visualizing difference. Running benchmarks can be in GitHub Actions or locally, storage can be in same repository master or dedicated branch, or standalone servers. It should be straightforward to setup this manually. Example of GitHub Action spec and blog from @vearutop, and an example on how it produces a PR comment.
⏫ Continuous benchmarking with gobenchdata
This tool uses go test -bench data in GitHub. It runs benchmarks, and uploads it as GitHub Pages for visualization. It is available as GitHub Action gobenchdata. This is useful to see benchmark trends. — @bobheadxi
Requirements
go install go.bobheadxi.dev/gobenchdata@latest
Automates comparing benchmarks with benchstat of two git references. It is available as GitHub Action benchdiff which runs benchstat of HEAD vs base branch. This is useful to see how benchmarks change with PRs in CI. — @WillAbides
Requirements
go install github.com/willabides/benchdiff/cmd/benchdiff
Automate comparing benchmarks with benchstat between HEAD and HEAD^1. It can be used to block CI pipelines if benchmarks deteriorate. It reports output as text in CLI. This cane be useful in CI or in local development. — @knqyf263
Requirements
go install github.com/knqyf263/cob@latest
⏫ Generate live traces with net/http/trace
This will add endpoints to your your server. If you don't have server running already in your process, you can start one. Then you can point pprof tool to this data. For production, hide this endpoint in separate port and path. More details in documentation trace, net/http/pprof.
package main
import (
"log"
"net/http"
"net/http/pprof"
)
func main() {
mux := http.NewServeMux()
mux.HandleFunc("/custom_debug_path/profile", pprof.Profile)
log.Fatal(http.ListenAndServe(":7777", mux))
}
Example
go tool pprof http://localhost:6060/debug/pprof/heap
go tool pprof http://localhost:6060/debug/pprof/profile?seconds=30
curl -o trace.out http://localhost:6060/debug/pprof/trace?seconds=5
⏫ Generate traces with go test
Produce a trace of execution of tests in pacakge.
go test -trace trace.out .
⏫ View traces with go tool trace
You can view traces interactively in browser with standard Go tooling. This web tool also shows network blocking profile, synchronization blocking profile, syscall blocking profile, scheduler latency profile.
go tool trace trace.out
This tool can be more illustrative of Go traces than standard Go traces. — @felixge
package main
import (
"net/http"
"github.com/felixge/fgtrace"
)
func main() {
http.DefaultServeMux.Handle("/debug/fgtrace", fgtrace.Config{})
http.ListenAndServe(":1234", nil)
}This tool can be more illustrative of Go profiles than standard Go profiling. — @felixge
package main
import (
"log"
"net/http"
_ "net/http/pprof"
"github.com/felixge/fgprof"
)
func main() {
http.DefaultServeMux.Handle("/debug/fgprof", fgprof.Handler())
go func() {
log.Println(http.ListenAndServe(":6060", nil))
}()
// <code to profile>
}This experimental approach illustrates collection of traces, intsrumentation, and visualization. It does not handle distributed traces. Likely useful for special cases or educational or research purposes. — @peterbourgon
Requirements
instrument your code with `trc` package
start UI server at port within same process
It has additional information like implementations of interface; promoted methods. The tool has nice minimalistic aesthetics. — Tapir Liu
golds ./...
Requirements
go install go101.org/golds@latest
This tool fetches the repo's readme as a man page replacement. — @christophberger
goman <mypackage>
Requirements
go install github.com/appliedgocode/goman@latest
This tool will generate instructions for shields.io to generate badge. It can read coverprofile. There is also GitHub Action that utilizes it and stores badge in the same repo, coverage-badge-go. — @AlexBeauchemin
gobadge -filename=coverage.out
gobadge -label="Go Coverage" -value=55.6% -color=blue -target=OTHER_README.md
gobadge -yellow=60 -green=80
gobadge -color=ff69b4
gobadge -link=https://github.com/project/repo/actions/workflows/test.yml
Requirements
go install github.com/AlexBeauchemin/gobadge@latest
It can be used as a command line tool, as Github action, or as a pre-commit hook. — @posener
goreadme
goreadme -variables -functions -methods -badge-godoc
goreadme -badge-godoc -constants -functions -methods -recursive -types -variables > README.md
Requirements
go install github.com/posener/goreadme/cmd/goreadme@latest
⏫ Run Turtle Graphics online with goplay.space
This absolutely adorable visualization is an excellent online resource to learn programming. — @iafan
package main
import (
"fmt"
)
func main() {
fmt.Println(`
draw mode
say Let's start...
right 18
color red
forward 7
say One...
right 144
forward 7
say Two...
right 144
forward 7
say Three...
right 144
forward 7
say Four...
right 144
forward 7
say We've got a star!
right 144
`)
}⏫ Run official vulnerability check with govulncheck
It uses static analysis of source code or a binary's symbol table to narrow down reports to only those that could affect the application. By default, govulncheck makes requests to the Go vulnerability database at https://vuln.go.dev. Requests to the vulnerability database contain only module paths, not code or other properties of your program. See https://vuln.go.dev/privacy.html for more. — Go Core team
govulncheck ./...
Example
vulnerability data from https://vuln.go.dev (last modified 2023-06-01 21:27:40 +0000 UTC).
Scanning your code and 1952 packages across 202 dependent modules for known vulnerabilities...
Your code is affected by 2 vulnerabilities from 1 module.
Vulnerability #1: GO-2023-1571
A maliciously crafted HTTP/2 stream could cause excessive CPU
consumption in the HPACK decoder, sufficient to cause a denial
of service from a small number of small requests.
More info: https://pkg.go.dev/vuln/GO-2023-1571
Module: golang.org/x/net
Found in: golang.org/x/net@v0.1.1-0.20221027164007-c63010009c80
Fixed in: golang.org/x/net@v0.7.0
Call stacks in your code:
cmd/kube-controller-manager/app/controllermanager.go:216:40: k8s.io/kubernetes/cmd/kube-controller-manager/app.Run calls k8s.io/apiserver/pkg/server.SecureServingInfo.Serve, which eventually calls golang.org/x/net/http2.ConfigureServer
requirements:
- go install golang.org/x/vuln/cmd/govulncheck@latest
Taint analysis is a technique for identifying the flow of sensitive data through a program. It can be used to identify potential security vulnerabilities, such as SQL injection or cross-site scripting (XSS) attacks, by understanding how this data is used and transformed as it flows through the code. This package provides tools to performs such analysis. Included tool is performing SQL injection taint analysis. — @picatz
sqli main.go
package main
import (
"database/sql"
"net/http"
)
func business(db *sql.DB, q string) {
db.Query(q) // potential sql injection
}
func run() {
db, _ := sql.Open("sqlite3", ":memory:")
mux := http.NewServeMux()
mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
business(db, r.URL.Query().Get("sql-query"))
})
http.ListenAndServe(":8080", mux)
}
func main() {
run()
}Example
./sql/injection/testdata/src/example/main.go:9:10: potential sql injection
Requirements
go install github.com/picatz/taint/cmd/sqli@latest
⏫ Run default static analysis with go vet
Official tool for static analysis of Go programs, with 27+ static analyzers. — official Go team
go vet ./...
⏫ Run custom static analysis tool with go vet
Standard go vet can be used to run custom analyzers binaries. Third party analyzers are supported. Lots of official analyzers not included by default into go vet. Analyzer has to satisfy interface and command described here https://pkg.go.dev/golang.org/x/tools/go/analysis. Refer for https://pkg.go.dev/golang.org/x/tools/go/analysis/passes for full list of official Go analyzers. — official Go team
go install golang.org/x/tools/go/analysis/passes/shadow/cmd/shadow
go vet -vettool=$(which shadow)
⏫ Run official static analyzers not included in go vet
There are many analyzers not included in go vet. These tools are experimental and may not work as expected (e.g. usesgenerics does not work). Refer to for full list https://pkg.go.dev/golang.org/x/tools/go/analysis. — official Go team
package main
import (
"golang.org/x/tools/go/analysis/multichecker"
"golang.org/x/tools/go/analysis/passes/atomicalign"
"golang.org/x/tools/go/analysis/passes/deepequalerrors"
"golang.org/x/tools/go/analysis/passes/fieldalignment"
"golang.org/x/tools/go/analysis/passes/nilness"
"golang.org/x/tools/go/analysis/passes/reflectvaluecompare"
"golang.org/x/tools/go/analysis/passes/shadow"
"golang.org/x/tools/go/analysis/passes/sortslice"
"golang.org/x/tools/go/analysis/passes/unusedwrite"
"golang.org/x/tools/go/analysis/passes/usesgenerics"
)
func main() {
multichecker.Main(
atomicalign.Analyzer, // checks for non-64-bit-aligned arguments to sync/atomic functions
deepequalerrors.Analyzer, // checks for the use of reflect.DeepEqual with error values
fieldalignment.Analyzer, // detects structs that would use less memory if their fields were sorted
nilness.Analyzer, // inspects the control-flow graph of an SSA function and reports errors such as nil pointer dereferences and degenerate nil pointer comparisons
reflectvaluecompare.Analyzer, // checks for accidentally using == or reflect.DeepEqual to compare reflect.Value values
shadow.Analyzer, // checks for shadowed variables
sortslice.Analyzer, // checks for calls to sort.Slice that do not use a slice type as first argument
unusedwrite.Analyzer, // checks for unused writes to the elements of a struct or array object
usesgenerics.Analyzer, // checks for usage of generic features added in Go 1.18
)
}⏫ Detect most common issues with staticcheck
Start custom linters with this well-known linter. It contains 150+ high quality low false positive rate linters. It is widely adopted by Open Source and tech companies. staticcheck.io. — @dominikh
staticcheck ./...
Requirements
go install honnef.co/go/tools/cmd/staticcheck@latest
This tool employs sophisticated static analysis techniques to catch Nil dereferences. More details in blog. — Uber
nilaway ./...
Requirements
go install go.uber.org/nilaway/cmd/nilaway@latest
This linting aggregator and runner is similar to staticcheck. It has 100+ linting rules. It is based on Go Code Review Comments style guide that is used in core Go project itself. It has styling, security, performance rules. It has minimal dependencies and implements rules itself. It exports all analysers into golang.org/x/tools/go/analysis toolchain. — @quasilyte
gocritic check ./...
Requirements
go install -v github.com/go-critic/go-critic/cmd/gocritic@latest
This tool has comprehensive list of linters. Owners of this aggregator keep track of active linters, their versions, and optimal configs. It contains many optimizations to make linters run fast by paralleism, distributing binaries and Docker images, utilising golang.org/x/tools/go/analysis toolchain.
⏫ Detect non-exhaustive switch and map with exhaustive
This go vet compatible analyzer checks for exhaustive switch statemnts and map literals. It works for enums with underyling integer, float, or string types (struct based enums are not supported). — @nishanths
exhaustive ./...
package token
type Token int
const (
Add Token = iota
Subtract
Multiply
Quotient
Remainder
)
package calc
import "token"
func f(t token.Token) {
switch t {
case token.Add:
case token.Subtract:
case token.Multiply:
default:
}
}
func g(t token.Token) string {
return map[token.Token]string{
token.Add: "add",
token.Subtract: "subtract",
token.Multiply: "multiply",
}[t]
}Example
calc.go:6:2: missing cases in switch of type token.Token: Quotient, Remainder
calc.go:15:9: missing map keys of type token.Token: Quotient, Remainder
Requirements
go install github.com/nishanths/exhaustive/cmd/exhaustive@latest
⏫ Detect structs with uninitialized fields with go-exhaustruct
This tool finds instatiations of structs with zero values. It supports struct tags to mark fields as optional. This may help to prevent unexpected zero values. — @xobotyi
exhaustruct ./...
type Shape struct {
Length int
Width int
volume int
Perimeter int `exhaustruct:"optional"`
}
// valid
var a Shape = Shape{
Length: 5,
Width: 3,
volume: 5,
}
// invalid, `volume` is missing
var b Shape = Shape{
Length: 5,
Width: 3,
}Requirements
go get -u github.com/GaijinEntertainment/go-exhaustruct/v3/cmd/exhaustruct
Find incorrect uses of reflect.SliceHeader, reflect.StringHeader, and unsafe casts between structs with architecture-sized fields. Reseach paper "Uncovering the Hidden Dangers Finding Unsafe Go Code in the Wild" presented at 19th IEEE International Conference on Trust, Security and Privacy in Computing and Communications (TrustCom 2020). — @jlauinger
go-safer ./...
Example
# github.com/jlauinger/go-safer/passes/sliceheader/testdata/src/bad/composite_literal
composite_literal/composite_literal.go:10:9: reflect header composite literal found
composite_literal/composite_literal.go:10:9: reflect header composite literal found
# github.com/jlauinger/go-safer/passes/sliceheader/testdata/src/bad/header_in_struct
header_in_struct/header_in_struct.go:16:2: assigning to reflect header object
Requirements
go install github.com/jlauinger/go-safer@latest
Identify expressions like T(x) where x is already has type T. This tool can identify conversions that force intermediate rounding. It also can overwrite files with fix. This tool is not using golang.org/x/tools/go/analysis toolchain. — @mdempsky
unconvert ./...
$ unconvert -v bytes fmt
GOROOT/src/bytes/reader.go:117:14: unnecessary conversion
abs = int64(r.i) + offset
^
GOROOT/src/fmt/print.go:411:21: unnecessary conversion
p.fmt.integer(int64(v), 16, unsigned, udigits)
^
Requirements
go install github.com/mdempsky/unconvert@latest
⏫ Detect global variables with gochecknoglobals
Global variables are an input to functions that is not visible in the functions signature, complicate testing, reduces readability and increase the complexity of code. However, sometimes global varaibles make sense. This tool skips such common scenarios. This tool can be used in CI, albeit it is very strict. This tool is useful for investigations. — @leighmcculloch
gochecknoglobals ./...
Example
/Users/nikolaydubina/Workspace/hugo/common/paths/path.go:64:5: fpb is a global variable
/Users/nikolaydubina/Workspace/hugo/common/paths/url.go:50:5: pb is a global variable
/Users/nikolaydubina/Workspace/hugo/common/text/position.go:52:5: positionStringFormatfunc is a global variable
/Users/nikolaydubina/Workspace/hugo/common/text/transform.go:26:5: accentTransformerPool is a global variable
/Users/nikolaydubina/Workspace/hugo/common/herrors/error_locator.go:40:5: SimpleLineMatcher is a global variable
Requirements
go install 4d63.com/gochecknoglobals@latest
Preallocating slices can sometimes significantly improve performance. This tool detects common scenarions where preallocating can be beneficial. This tool is not using golang.org/x/tools/go/analysis toolchain. — @alexkohler
prealloc ./...
Example
tools/gopls/internal/lsp/source/completion/completion.go:1484 Consider preallocating paths
tools/gopls/internal/lsp/source/completion/package.go:54 Consider preallocating items
tools/gopls/internal/lsp/template/symbols.go:205 Consider preallocating ans
tools/gopls/internal/lsp/template/completion.go:199 Consider preallocating working
tools/gopls/internal/lsp/tests/util.go:32 Consider preallocating notePositions
tools/gopls/internal/lsp/tests/util.go:240 Consider preallocating paramParts
tools/gopls/internal/lsp/tests/util.go:282 Consider preallocating result
tools/gopls/internal/lsp/tests/util.go:309 Consider preallocating got
Requirements
go install github.com/alexkohler/prealloc@latest
It is common guideline to avoid renaming imports unless there are collisions. This tool detects where original pacakge name would not collide. This tool is useful for investigations. This tool is not using golang.org/x/tools/go/analysis toolchain. — @alexkohler
unimport ./...
Example
pkg/apis/apiserverinternal/v1alpha1/zz_generated.conversion.go:29 unnecessary import alias runtime
pkg/apis/apiserverinternal/v1alpha1/zz_generated.conversion.go:30 unnecessary import alias apiserverinternal
pkg/apis/apps/v1/zz_generated.conversion.go:25 unnecessary import alias unsafe
pkg/apis/apps/v1/zz_generated.conversion.go:30 unnecessary import alias conversion
pkg/apis/apps/v1/zz_generated.conversion.go:31 unnecessary import alias runtime
pkg/apis/apps/v1/zz_generated.conversion.go:32 unnecessary import alias intstr
pkg/apis/apps/v1/zz_generated.conversion.go:33 unnecessary import alias apps
pkg/apis/apps/v1/zz_generated.conversion.go:34 unnecessary import alias core
pkg/apis/apps/v1beta1/zz_generated.conversion.go:25 unnecessary import alias unsafe
pkg/apis/apps/v1beta1/zz_generated.conversion.go:27 unnecessary import alias v1beta1
pkg/apis/apps/v1beta1/zz_generated.conversion.go:30 unnecessary import alias conversion
pkg/apis/apps/v1beta1/zz_generated.conversion.go:31 unnecessary import alias runtime
Requirements
go install github.com/alexkohler/unimport@latest
Ensure that import aliases take one of the allowed values. — @julz
importas -alias knative.dev/serving/pkg/apis/autoscaling/v1alpha1:autoscalingv1alpha1 -alias knative.dev/serving/pkg/apis/serving/v1:servingv1 ./...
package main
import (
v1alpha1 "knative.dev/serving/pkg/apis/autoscaling/v1alpha1" // want `import "knative.dev/serving/pkg/apis/autoscaling/v1alpha1" imported as "v1alpha1" but must be "autoscalingv1alpha1" according to config`
v1 "knative.dev/serving/pkg/apis/serving/v1" // want `import "knative.dev/serving/pkg/apis/serving/v1" imported as "v1" but must be "servingv1" according to config`
)
func main() {
...Requirements
go install github.com/julz/importas/cmd/importas@latest
⏫ Detect inconsistent import aliases with consistentimports
It greatly helps to navigate large codebases when imports have the same aliases. — @nikolaydubina
consistentimports ./...
Example
-: "k8s.io/utils/net" netutils:4 netutil:1
-: "k8s.io/client-go/listers/core/v1" corelisters:1 listersv1:1 v1listers:1
-: "k8s.io/client-go/informers/core/v1" coreinformers:1 informers:1
-: "k8s.io/api/rbac/v1" rbacv1:4 v1:2
-: "k8s.io/apimachinery/pkg/runtime" runtime:3 kruntime:1
-: "k8s.io/api/imagepolicy/v1alpha1" imagepolicyv1alpha1:1 v1alpha1:1
-: "k8s.io/kubernetes/plugin/pkg/admission/podtolerationrestriction/apis
Requirements
go install github.com/nikolaydubina/consistentimports@latest
It is common guideline to avoid naked returns. Naked return is when function has named return, and return statement does not specify value. This tool is useful for investigations. — @alexkohler
nakedret ./...
Example
/kubernetes/pkg/controller/podautoscaler/replica_calculator.go:421:2: naked return in func `groupPods` with 44 lines of code
/kubernetes/pkg/kubelet/container/helpers.go:374:2: naked return in func `MakePortMappings` with 36 lines of code
/kubernetes/pkg/kubelet/config/config.go:350:2: naked return in func `filterInvalidPods` with 17 lines of code
/kubernetes/pkg/kubelet/config/config.go:449:3: naked return in func `checkAndUpdatePod` with 38 lines of code
/kubernetes/pkg/kubelet/config/config.go:471:2: naked return in func `checkAndUpdatePod` with 38 lines of code
/kubernetes/cmd/kube-controller-manager/app/controllermanager.go:717:2: naked return in func `createClientBuilders` with 19 lines of code
/kubernetes/pkg/proxy/topology.go:77:3: naked return in func `CategorizeEndpoints` with 98 lines of code
/kubernetes/pkg/proxy/topology.go:111:3: naked return in func `CategorizeEndpoints` with 98 lines of code
/kubernetes/pkg/proxy/topology.go:119:3: naked return in func `CategorizeEndpoints` with 98 lines of code
/kubernetes/pkg/proxy/topology.go:137:2: naked return in func `CategorizeEndpoints` with 98 lines of code
Requirements
go install github.com/alexkohler/nakedret/cmd/nakedret@latest
Mixing pointer and value method receivers for the same type is discouraged, as per commong guideline Go wiki and Google Go style guide. — @nikolaydubina
smrcptr ./...
type Pancake struct{}
func NewPancake() Pancake { return Pancake{} }
func (s *Pancake) Fry() {}
func (s Pancake) Bake() {}Example
smrcptr/internal/bakery/pancake.go:7:1: Pancake.Fry uses pointer
smrcptr/internal/bakery/pancake.go:9:1: Pancake.Bake uses value
Requirements
go install github.com/nikolaydubina/smrcptr@latest
Vertical function ordering is declaring functions before they are used. Based on 'Clean Code' by Robert.C.Martin. — @nikolaydubina
vertfn --verbose ./...
Requirements
go install github.com/nikolaydubina/vertfn@latest
This tool goes beyond just vertical ordering of function declarations, it also tracks many other types of symbols. — @devnev
refdir --verbose ./...
Requirements
go install github.com/devnev/refdir@latest
⏫ Detect tests with wrong t.Parallel() usage with paralleltest
This linter checks for incorroect usage of t.Parallel() calls. It will detect if t.Parallel() is missing. — @kunwardeep
paralleltest ./...
Example
/kubernetes/pkg/scheduler/framework/plugins/nodeunschedulable/node_unschedulable_test.go:28:1: Function TestNodeUnschedulable missing the call to method parallel
/kubernetes/pkg/scheduler/framework/plugins/nodevolumelimits/csi_test.go:68:1: Function TestCSILimits missing the call to method parallel
/kubernetes/pkg/scheduler/framework/plugins/nodevolumelimits/csi_test.go:480:2: Range statement for test TestCSILimits missing the call to method parallel in test Run
/kubernetes/pkg/scheduler/framework/plugins/nodevolumelimits/non_csi_test.go:81:1: Function TestEphemeralLimits missing the call to method parallel
Requirements
go install github.com/kunwardeep/paralleltest@latest
This linter checks for incorroect usage of t.Parallel() calls. — @moricho
go vet -vettool=`which tparallel` ./...
Example
testdata/src/sample/table_test.go:7:6: Test_Table1 should use t.Cleanup
testdata/src/sample/table_test.go:7:6: Test_Table1 should call t.Parallel on the top level as well as its subtests
testdata/src/sample/table_test.go:30:6: Test_Table2's subtests should call t.Parallel
Requirements
go install github.com/moricho/tparallel/cmd/tparallel@latest
This tool has heuristics to detect magic numbers. — @tommy-muehle
mnd ./...
Example
/go-mnd/examples/bad/main.go:18:23: Magic number: 200, in <condition> detected
/go-mnd/examples/bad/main.go:11:12: Magic number: 2, in <assign> detected
Requirements
go install github.com/tommy-muehle/go-mnd/v2/cmd/mnd@latest
This tool detects repeated strings. — @jgautheron
goconst -min-occurrences 5 -output json ./... | jq
Example
"not reached": [
{
"Filename": "tpl/internal/go_templates/texttemplate/hugo_template.go",
"Offset": 7916,
"Line": 267,
"Column": 8
},
{
"Filename": "tpl/internal/go_templates/texttemplate/exec.go",
"Offset": 15056,
"Line": 525,
"Column": 8
},
{
"Filename": "tpl/internal/go_templates/texttemplate/exec.go",
"Offset": 21354,
"Line": 699,
"Column": 8
},
{
"Filename": "tpl/internal/go_templates/texttemplate/exec.go",
"Offset": 28145,
"Line": 903,
"Column": 8
},
...
Requirements
go install github.com/jgautheron/goconst/cmd/goconst@latest
⏫ 🔥 Detect bound checks with pat/boundcheck
This tool detects bound checks in source code by anaylisng compiled code. This is useful for audit. — @maruel
boundcheck -pkg ./cmd/nin | less -R
Requirements
go install github.com/maruel/pat/cmd/...@latest
Congitive Complexity as defined in this tool can be more illustrative than Cyclometric Complexity. Research paper "Cognitive Complexity - a new way of measuring understandability", 2021. — @uudashr
gocognit .
// Complexity Cyclomatic=4 Cognitive=7
// Cognitive complexity give higher score compare to cyclomatic complexity.
func SumOfPrimes(max int) int { // +1
var total int
for i := 1; i < max; i++ { // +1 (cognitive +1, nesting)
for j := 2; j < i; j++ { // +1 (cognitive +2, nesting)
if i%j == 0 { // +1
continue OUT
}
}
total += i
}
return total
}
// Complexity Cyclomatic=4 Cognitive=1
// Cognitive complexity give lower score compare to cyclomatic complexity.
func GetWords(number int) string { // +1
switch number {
case 1: // +1 (cognitive 0)
return "one"
case 2: // +1 (cognitive 0)
return "a couple"
case 3: // +1 (cognitive 0)
return "a few"
default:
return "lots"
}
}Example
21 main (BasicSymtabConverter).SymtabFileToTreemap basic_converter.go:23:1
12 symtab parseGoSymtabLine symtab/go_symtab_parser.go:37:1
11 main main main.go:30:1
8 symtab EqSymbolName symtab/symbol_name_parser.go:12:1
7 symtab ParseSymbolName symtab/symbol_name_parser.go:32:1
7 symtab Test_parseGoSymtabLine symtab/go_symtab_parser_private_test.go:5:1
4 symtab Test_ParseSymbolName symtab/symbol_name_parser_private_test.go:5:1
3 main updateNodeNamesWithByteSize main.go:99:1
3 main unique basic_converter.go:119:1
3 symtab (GoSymtabParser).ParseSymtab symtab/go_symtab_parser.go:14:1
2 fmtbytecount ByteCountIEC fmtbytecount/format_bytecount.go:3:1
Requirements
go install github.com/uudashr/gocognit/cmd/gocognit@latest
Cyclomatic complexity is a code quality metric which can be used to identify code that needs refactoring. It measures the number of linearly independent paths through a function's source code. For example, excessive usage of nested if and for leads to increased cyclomatic complexity. This tool can report top-N and over, which makes it suitable for CI as a linter and manual investigation. — @fzipp
gocyclo .
Example
$ gocyclo -over=5 .
34 examplemodule (*With32FieldsFeatureTransformer).Fit cmd/generate/tests/with32fieldsfp.go:48:1
24 main parseCode cmd/generate/parser.go:83:1
13 examplemodule (*AllTransformersFeatureTransformer).Fit cmd/generate/tests/alltransformersfp.go:27:1
12 examplemodule (*EmployeeFeatureTransformer).Fit cmd/generate/tests/employeefp.go:26:1
11 transformers (*CountVectorizer).TransformInplace transformers/textprocesors.go:84:1
11 structtransformer (*StructTransformer).Transform structtransformer/structtransformer.go:38:1
11 examplemodule (*LargeMemoryTransformerFeatureTransformer).Fit cmd/generate/tests/largememorytransformerfp.go:25:1
10 examplemodule (*WeirdTagsFeatureTransformer).Fit cmd/generate/tests/weirdtagsfp.go:24:1
8 transformers (*SampleNormalizerL2).TransformInplace transformers/samplenormalizers.go:58:1
Requirements
go install github.com/fzipp/gocyclo/cmd/gocyclo@latest
This linter calculates cyclomatic copmlexity of functions or packages. It can select minimum compexlity and act as blocking linter in CI pipelines. The key offering from this linter is that it can calculate avg cyclomatic compelxity on package. — @bkielbasa
cyclop ./...
# to find packages with avg cyclomatic copmlexity above maximum
cyclop -packageAverage 5 -maxComplexity 10000 ./...
Example
/kubernetes/test/integration/scheduler/scoring/priorities_test.go:17:1: the average complexity for the package scoring is 6.100000, max is 5.000000
/kubernetes/test/integration/serviceaccount/service_account_test.go:17:1: the average complexity for the package serviceaccount is 10.666667, max is 5.000000
/kubernetes/test/integration/volume/persistent_volumes_test.go:17:1: the average complexity for the package volume is 6.157895, max is 5.000000
/kubernetes/test/list/main_test.go:17:1: the average complexity for the package main is 5.461538, max is 5.000000
/kubernetes/test/typecheck/main_test.go:17:1: the average complexity for the package main is 5.916667, max is 5.000000
/kubernetes/third_party/forked/golang/net/dnsclient_test.go:10:1: the average complexity for the package net is 5.333333, max is 5.000000
Requirements
go install github.com/bkielbasa/cyclop@latest
⏫ Calculate age of comments with go-commentage
This go vet compatible tool analyses AST and git and collects details on how far comments drift from code they describe. — @nikolaydubina
go-commentage -min-days-behind 360 ./...
Example
kubernetes/pkg/util/ipset/ipset.go:283:1: "CreateSet": doc_last_updated_behind_days(1336.83)
kubernetes/pkg/util/ipset/ipset.go:296:1: "createSet": doc_last_updated_behind_days(1603.17)
kubernetes/pkg/util/ipset/ipset.go:320:1: "AddEntry": doc_last_updated_behind_days(1578.10)
kubernetes/pkg/util/ipset/ipset.go:332:1: "DelEntry": doc_last_updated_behind_days(1578.10)
kubernetes/pkg/util/ipset/ipset.go:340:1: "TestEntry": doc_last_updated_behind_days(450.07)
Requirements
# get latest version of git
go install github.com/nikolaydubina/go-commentage@latest
Linter for checking that your code uses short syntax for if statements whenever possible. However, as of 2023-05-26, it is not maitaned and is not working. — @esimonov
ifshort ./...
// bad
func someFunc(k string, m map[string]interface{}) {
_, ok := m[k]
if !ok {
return
}
err := otherFunc1()
if err != nil {
otherFunc2(err)
}
}
// good
func someFunc(k string, m map[string]interface{}) {
if _, ok := m[k]; !ok {
return
}
if err := otherFunc1(); err != nil {
otherFunc2(err)
}
}Requirements
go install github.com/esimonov/ifshort@latest
⏫ Visualize struct layout with structlayout
Display the byte offset and size of each field, respecting alignment/padding. — @dominikh
structlayout -json bytes Buffer | structlayout-svg -t "bytes.Buffer" > /tmp/struct.svg
Requirements
go install github.com/ajstarks/svgo/structlayout-svg@latest
go install honnef.co/go/tools/cmd/structlayout@latest
⏫ Rely on compiler for stricter Enums
For compile time blocking of: accidental arithmetics; implicit cast of untyped constants; all operators except == and !=; — simply wrap into a struct in separate package and do not export field. example.
package color
type Color struct{ c uint }
var (
Undefined = Color{}
Red = Color{1}
Green = Color{2}
Blue = Color{3}
)⏫ Analyze function callsites with go-callsite-stats
Scrape callsite information about functions to lern better how functions are beign used. This can help in refactoring, naming, OOP. This tool calcuates frequency of names on assignments in returns and frequency of names in arguments. This can be used to detect ignored returns as well. — @nikolaydubina
go-callsite-stats ./...
x16: (no assignments) = execHostnameTest(serviceAddress:7)
(nodePortAddress:3)
(nodePortAddress0:3)
(nodePortAddress1:2)
(clusterIPAddress:1)
x16: pod:10, err:12 = CreatePod(client:11, namespace:10, nil:9, pvclaims:6, false:7, execCommand:2)
clientPod:1 (c:2, ns:2, podCount:2, true:3)
_:1 (pod:1, pod:1, pvclaims:2, false:2)
err:1 (ctx:1, nil:1, createdClaims:1, pvcClaims:1)
(namespace:1, nameSpace:1, podTemplate:1)
(, basePod:1)
x16: (no assignments) = GET()
x16: deployment:11, err:14 = UpdateDeploymentWithRetries(c:14, ns:14, deploymentName:3, applyUpdate:1, poll:1,pollShortTimeout:1)
_:2 (client:1, namespace:1, pollTimeout:1)
deploymentWithUpdatedReplicas:1 (applyUpdate:1, pollInterval:1, name:1)
x16: err:16 = waitForDefinition(schemaFoo:12
(schemaWaldo:3)
(expect:1)
Requirements
go install github.com/nikolaydubina/go-callsite-stats@latest