$ docker run --rm cytopia/gofmt --help

Usage: cytopia/gofmt [flags] [path...]
       cytopia/gofmt [--ci] [-r rule] [-se] [path...]
       cytopia/gofmt --help

Dockerized version of gofmt with an addition to fail (exit 1) in case of file changes.

Additional wrapper features:
----------------------------
--ci      This option will print the diff to stdout (similar to '-d') and if a diff
          exists it will fail with exit 1.
          Can only be combined with '-r rule', '-s' and '-e'.
          To be used in continuous integration with explicit failing.

Default gofmt flages:
----------------------------
-d        Do not print reformatted sources to standard output.
          If a file's formatting is different than gofmt's, print diffs
          to standard output.
-e        Print all (including spurious) errors.
-l        Do not print reformatted sources to standard output.
          If a file's formatting is different from gofmt's, print its name
          to standard output.
-r rule   Apply the rewrite rule to the source before reformatting.
-s        Try to simplify code (after applying the rewrite rule, if any).
-w        Do not print reformatted sources to standard output.
          If a file's formatting is different from gofmt's, overwrite it
          with gofmt's version. If an error occurred during overwriting,
          the original file is restored from an automatic backup.

# Print diff to stdout and exit 0
$ docker run --rm -v $(pwd):/data cytopia/gofmt -d .

# Print diff to stdout and exit > 0 if diff occurs
$ docker run --rm -v $(pwd):/data cytopia/gofmt --ci .