Pre-commit Docker image

Pre-commit is a tool created by Yelp that allows you to run pre-commit sanity checks against your repo, to do things like ensuring private keys aren't being added etc. This image packages pre-commit in a docker-container, so you can ship it with a setup script you might be using to setup local development environment.

Usage

• Create .pre-commit-config.yaml in the root of your repo. For example

  - repo: git://github.com/pre-commit/pre-commit-hooks
    sha: master  # Use the ref you want to point at
    hooks:
      - { id: check-case-conflict }
      - { id: check-merge-conflict }
      - { id: check-symlinks }
      - { id: check-json }
      - { id: check-yaml }
      - { id: detect-private-key }
      - { id: end-of-file-fixer }
      - { id: trailing-whitespace }

• Add pre-commit script to .git/hooks/pre-commit

  #!/bin/sh
  toplevel="`git rev-parse --show-toplevel`"
  NAME="`basename "$toplevel"`_precommit"
  
  cd "$toplevel"
  
  # Find container executable; either podman or docker
  if command -v podman > /dev/null 2>&1; then
      container_exec=podman
  elif command -v docker > /dev/null 2>&1; then
      container_exec=docker
  else
      echo "No container executable found! Looked for \`podman' and \`docker'."
      exit 1
  fi
  
  # Is there already a container for this source directory?
  test -n "`"$container_exec" ps -a -q --no-trunc --filter 'name=^/?'"$NAME"'$'`"
  CONTAINER_EXISTS=$?
  
  if [ "$CONTAINER_EXISTS" -eq 0 ]; then
      "$container_exec" restart "$NAME" >/dev/null && "$container_exec" attach --no-stdin "$NAME"
  else
      "$container_exec" run -t -v $(pwd):/pre-commit --name "$NAME" alexs77/pre-commit
  fi

• Create an empty commit to test

  git commit --allow-empty -m "Test pre-commit"

Note

• If you are going to use a pre-commit plugin that needs dependencies not packaged in this image, you can extend this image and install the dependencies you need
• You might need to change the command, add volumes etc, based on your needs. For example, if you add { id: detect-aws-credentials } to .pre-commit-config.yaml, you have to mount the directory holding your aws credentials. The docker command (as in the pre-commit script) would then become

  "$container_exec" run -t -v $(pwd):/pre-commit -v $HOME/.aws:/root/.aws:ro --name $NAME alexs77/pre-commit