don/README.md

don

Package don is a little helper if you need to check for the readiness of something. This could be a command to run (like ssh) or a db.Ping() for check of the readiness of a database container.

Use as commandline tool

Download the tool from the download page or install via brew:

brew tap xsteadfastx/tap [https://github.com/xsteadfastx/homebrew-tap](https://github.com/xsteadfastx/homebrew-tap)
brew install don
don -t 15m -r 15s -c "ssh -o StrictHostKeyChecking=no -o ConnectTimeout=10 root@container"

This example checks every 15 seconds if the ssh container is ready. It would timeout with an error after 15 minutes.

Use as a library

If you want to use don as a library, it just takes a func() bool in don.Ready() have a function that runs the readiness check and returns true or false if its ready or not. The second argument is the overall timeout and the third argument is the check interval. Import it like this:

import go.xsfx.dev/don

Doing the readiness check like this:

if err := don.Ready(
	func() bool {
		db, err := sql.Open("oracle", dbConn)
		if err != nil {
			log.Warn().Err(err).Str("dbConn", dbConn).Msg("could not open connection")

			return false
		}

		if err := db.Ping(); err != nil {
			log.Warn().Err(err).Str("dbConn", dbConn).Msg("could not ping")

			return false
		}

		return true
	},
	10*time.Minute,
	30*time.Second,
); err != nil {
	log.Error().Err(err).Msg("received error")
	teardown(pool, resource, tmpState.Name())
	os.Exit(1)
}

Functions

func Cmd

func Cmd(c string) func() bool

Cmd returns a func() bool for working with don.Ready(). It executes a command and returns a true if everything looks fine or a false if there was some kind of error.

func Ready

func Ready(f func() bool, timeout time.Duration, retry time.Duration, bar bool) error

Ready takes a function that executes something and returns a bool to indicate if something is ready or not. It returns an error if it timeouts.