Ever forgot when your certificates are due to expire, and you have a published OpenID Connect JWKS ?
./jwksformatter -template templates/iCalendar.tmpl -uri https://api.byu.edu/.well-known/byucerts
And just throw certs.ics at Outlook or whatever calendaring application you use. Otherwise just use templates/csv.tmpl and import the output CSV into Excel or Google Sheets, or use template/markdown.tmpl and have a nice Markdown table like this:
| Key ID | Serial | Use | Expires | Subject | Issuer |
|---|---|---|---|---|---|
f86d695a3866466fbf57a5fea5f56cc9 |
3776378436100916921094765356845154712 |
sig |
2021/06/01 | CN=wso2-is.byu.edu,O=Brigham Young University,L=Provo,ST=Utah,C=US |
CN=DigiCert SHA2 High Assurance Server CA,OU=www.digicert.com,O=DigiCert Inc,C=US |
Note that this tool only works with JWKS' which include the public certificate (x5c) as it needs to extract the Valid To attribute of the certificate. You can also define your own Go template to provide your own output format.