Go package / latchfile

Atomic file writes for Go.

Save configuration, checkpoints, and generated files in a single step. Latchfile writes to a temporary file beside the destination and renames it into place when the write succeeds.

Read the docs

Documentation

Recipes for settings, exports, and checkpoints
What survives a crash?
Coordinating concurrent writers
Filesystem and platform notes
Troubleshooting failed writes

Quickstart

Pass the destination, the bytes you want to save, and the file mode. Handle the returned error before continuing.

settings.go

import "example.org/latchfile"

data := []byte("{\"workers\":4}\n")
err := latchfile.WriteFile("settings.json", data, 0644)
if err != nil {
    return err
}

API reference

WriteFile(path, data, mode) error: Writes the supplied bytes and replaces the destination. The parent directory must already exist.
Write(path, mode, func(io.Writer) error) error: Streams data through a callback. Returning an error discards the temporary file.