Basic Yaml Loading with additional functionality, i.e. resolve file depedencies, resolve variables, deep merge hierachies.

Useful for loading improved serverless configuration. For yaml loading this package uses js-yaml.

$ npm install --save yaml-boost

Resolve content with variables at given refPath.

Load filePath with given variables.

As provided by js-yaml through safeDump

const yaml = require('yaml-boost');

yaml.load('config.yaml');

Matching yaml.dump() function is also available.

Works identical to how this is defined for serverless here.

Both yml and yaml file endings are supported.

${file(./path/to/file.yml), key1=value1&key2=value2}

You can reference packages by using

${require(PACKAGE):path.to.key.in.module}

Reference js instead of yaml files.

${file(./path/to/file.js)}

The reference file needs to export simple object containing configuration

module.exports = {};

Reference function inside js file.

${fileFn(./path/to/file.js)}

The reference file needs to export simple function returning an object. Available variables are passed in.

module.exports = (args) => ({ args });

Once can reference files relative to the current file by using ^ as a prefix like so

${file(^/subfolder/of/current/file.yml)}

Analogue to the << yaml syntax we can use <<< to deep merge into the current nesting level. This is helpful when merging files into already existing hierarchies.

Example:

data:
  - list entry one

<<<:
  - data:
      - list entry two
  - other: things

results in

data:
  - list entry one
  - list entry two
other: things

Define serverless.js as

const path = require('path');
const minimist = require('minimist');
const yaml = require('yaml-boost');

module.exports = yaml.load(path.join(__dirname, 'serverless.core.yml'), minimist(process.argv.slice(2)));

Then instead of defining serverless.yml, define your config in serverless.core.yml.