watchers/File

godoc

import "barista.run/base/watchers/file"

The file package provides the ability to watch for changes to a single file, in a way that works across deletions of the tree and handles non-existence of the file or part of the path to the file. It also uses coalescing notifications, so extra processing is minimised.

Create a watcher: w := file.Watch("/var/run/something.pid"), and remember to unsubscribe using w.Unsubscribe().

Then simply listen for updates to the Updates channel, and errors on the Errors channel, e.g.

for {
	select {
		case <-w.Updates:
			// Something happened, query file and update module output.
		case e := <-w.Errors:
			sink.Error(e)
			return  // No need to unsubscribe on errors.
	}
}