myw / dcwr

Run a command inside Docker Compose as if it were local

DCWR - Docker Compose Wrap Run

Run a command inside Docker Compose as if it were local

Documentation

Command-line usage:

dcwr [-h|--help] [-f|--file compose-file] [-q|--quiet] [-n|--no-run] [-k|--keep] [*]

  Transparently run a command inside a Docker Compose service

  dcwr runs the command inside a new Docker container for the Docker Compose
  service specified, as if it were running locally. It does this by taking
  every command argument that points to a file or directory, mounting it
  inside the Docker container and replacing it with the mount point
  destination.

  By default, it prints the final docker-compose command before running it.

Arguments:
  -h --help   - show this usage info
  -f --file   - path to docker-compose.yml file to use
                [defaults to ./docker-compose.yml]
  -q --quiet  - do not print the final command before running
  -n --no-run - do not run the command, just print it
  -k --keep   - do not add --rm to docker-compose run (default behavior)
  [*]         - arguments to docker-compose run
                [options, service name, command, etc]

Example:
  $ dcwr -n service-foo cmd-bar arg-baz README.md . -narf LICENSE /usr/share/man/man1/ls.1

  docker-compose run \
    --rm \
    --volume=/mydir/README.md:/tmp/9ZnUSxR1/4-README.md \
    --volume=/mydir/.:/tmp/9ZnUSxR1/5-. \
    --volume=/mydir/LICENSE:/tmp/9ZnUSxR1/7-LICENSE \
    --volume=/usr/share/man/man1/ls.1:/tmp/9ZnUSxR1/8-ls.1 \
    service-foo \
      cmd-bar \
        arg-bazbaz \
        /tmp/9ZnUSxR1/4-README.md \
        /tmp/9ZnUSxR1/5-. \
        -narf \
        /tmp/9ZnUSxR1/7-LICENSE \
        /tmp/9ZnUSxR1/8-ls.1

Dependencies

• Docker
• Docker Compose
• bash >= 2.0
• Standard POSIX system utilities, specifically: cat, env, mktemp.

Installation

Download or clone the repository and move, copy, or link dcwr into a directory on your $PATH, or add the directory it's in to your $PATH through your shell's login environment settings. The best practice on most systems is to copy dcwr into $HOME/bin if installing it for just a single user, or /usr/local/bin if installing it for everyone.

Caveats

This is a convenience utility and its approach fundamentally cannot account for all edge cases so it has some important caveats:

• Arguments that are not strictly filenames, like -f/foobar/baz, or --loc=path/to/file, are not modified.
• New files/directories (i.e. that do not already exist on the host system) cannot be mounted this way: you will have to touch or mkdir them first on your own
• Commands that reference other files that are not specified in the container or otherwise mounted will not work without additional options
• Docker images that do not tolerate mounts into a temp directory will not work
• The executing command is always at the mercy of the image, so there are lots of other potential ways to "break" the expected behavior