Formatter: expose CLI options to write formatting, for check mode and for recursive screening in repo

[thibaut-lo]

Thanks for lot for making this util.

I have been using it to

• format Dockerfiles in my git repo
• check formatting and raise error if formatting differs from existing format
  in CI and with a shell util in dev environment that is "agnostic" (a task runner (Makefile here) not linked to vscode for example).

That would be cool if dockerfile-utils format exposes CLI options to match these use case.

A bit like black --check --diff . and black . for another well-known formatted (python here).

It could be dockerfile-utils format --write --recursive . (-w for write and -r for recursively find Dockerfiles, with maybe an optional --regex that defaults to "Dockerfile")
and dockerfile-utils format --check --recursive . to raise errors if the formatting differs.

The current syntax is a bit cumbersome (below).

make format-dockerfiles:
	@echo "Formatting Dockerfiles... "
	@cd .. && for file in $$( (git ls-files ; git ls-files --others --exclude-standard) | sort -u  | grep 'Dockerfile'); do \
		tmpFormattedDockerfile=$$(mktemp) ; \
		echo -n "Formatting $$file file... " ; \
		trap "rm -f $$tmpFormattedDockerfile" EXIT ; \
		dockerfile-utils format -t $$file > "$$tmpFormattedDockerfile" && mv "$$tmpFormattedDockerfile" $$file ; \
		echo OK && rm -f $$tmpFormattedDockerfile ; \
    done; echo Dockerfiles formatted
.PHONY: format-dockerfiles

check-dockerfiles: ## Check coding style
	@echo "Checking Dockerfiles... "
	@cd .. && for file in $$( (git ls-files ; git ls-files --others --exclude-standard) | sort -u  | grep 'Dockerfile'); do \
		tmpFormattedDockerfile=$$(mktemp) ; \
		trap "rm -f $$tmpFormattedDockerfile" EXIT ; \
		echo -n "Checking $$file file... " ; \
		dockerfile-utils format -t $$file > "$$tmpFormattedDockerfile" ; \
		if ! cmp $$file $$tmpFormattedDockerfile ; then \
			echo "Error: $$file is not properly formatted." ; \
			exit 1 ; \
		fi ; \
		echo OK && rm -f $$tmpFormattedDockerfile ; \
    done; echo Dockerfiles checked
.PHONY: check-dockerfiles

[rcjsuen]

Hi @thibaut-lo, thank you for your interest in this project.

Regarding "checking", so you mean if you specified "spaces" but "tabs" were found the program would return a non-zero return code? Would it still format anything? I guess not if it is just a "check"?

[thibaut-lo]

Apologies for the delay in answering @rcjsuen, I missed your reply.

Would it still format anything? I guess not if it is just a "check"?

You're right, this check option doesn't perform formatting, it just check that the current formatting complies (ie no change would be applied if formatting was done). Otherwise, it should fail, return a non-zero code.
We use it in CI, to ensure that pull requests / merge requests have formatted their code correctly.

[thibaut-lo]

In the meantime, I have made that small script to add that --check option. It would need to be generalized (I hardcode my configuration here, ie 4 spaces).

#!/bin/bash
#
# Format all Dockerfiles in the current git repo using dockerfile-utils formatter tool.
# Check formatting only if argument  --check is passed.
#
# Usage:    format-dockerfiles.sh [--check]

set -e

# Check if git is installed
if ! command -v git &>/dev/null; then
    echo "git could not be found. Please install git and try again."
    exit 1
fi

root_dir=$(git rev-parse --show-toplevel)

check_only=false
if [[ $1 == "--check" ]]; then
    check_only=true
fi

if $check_only; then
    echo "Checking format of Dockerfiles with dockerfile-utils..."
else
    echo "Formatting Dockerfiles with dockerfile-utils"
fi

for file in $( (
    cd "$root_dir" && git ls-files
    cd "$root_dir" && git ls-files --others --exclude-standard # new uncommitted files
) | sort -u | grep 'Dockerfile'); do

    tmpFormattedDockerfile=$(mktemp)
    trap 'rm -f $tmpFormattedDockerfile' EXIT

    dockerfile-utils format --spaces 4 "$root_dir"/"$file" >"$tmpFormattedDockerfile"

    if $check_only; then
        if ! cmp "$root_dir"/"$file" "$tmpFormattedDockerfile"; then
            echo "Error: $file is not properly formatted."
            echo "(hint) fix with \`make format\`"
            exit 1
        fi
    else
        mv "$tmpFormattedDockerfile" "$root_dir"/"$file"
    fi

    rm -f "$tmpFormattedDockerfile"

done

if $check_only; then
    echo "Dockerfiles format checked"
else
    echo "Dockerfiles formatted"
fi