clink: containerize all the things

Warning: This is extremely beta. Use at your own risk.

What is it?

TL;DR: When you type a command that's not installed on your system, clink looks for and launches the appropriate Docker container.

This is useful if you often run desktop applications in containers, and are sick of creating aliases for long and unwieldy docker run commands.

clink takes advantage of the command not found shell hook. When you run a command that's not installed, it looks for an appropriate match among your local Docker images, and tries to start a container, passing it things like the following:

• Devices:

  • Lots of them

• Environment variables:

  • All of them.

• Volumes, such as:

  • /etc/passwd
  • /etc/group
  • /etc/localtime
  • and perhaps most importantly, your current working directory. If this is your homedir, your profile setup may do funny things in the container. If you are in /, well, you get the idea.

Installation

$ git clone https://github.com/soulshake/clink.git

Add it to your profile:

source PATH_TO_CLONED_REPO/clink

Bash is supported. Zsh might work.

Usage

Build a docker image with the name of the command you want to run:

$ docker build -t COMMAND_NAME .

Then just run COMMAND_NAME as usual and clink will run a Docker container of the corresponding image.

Like all sufficiently advanced technology, this is a dirty hack under no circumstances to be confused with magic.

How it works

When a command name is sent to the shell, the shell looks in $PATH for matches.

If an executable is found in your path, your shell will run it like it normally does.

Missing commands are handled a bit differently depending on your shell.

If no matching executable is found in your path, your shell will look for a function named command_not_found_handle (in the case of bash) or command_not_found_handler (in the case of zsh). By sourcing clink in your profile, you are defining these functions, which will take over. clink looks for Docker images on your system with a matching tag and attempts to run them for you.

which integration

Obviously, Docker images don't appear in your system $PATH:

$ /bin/which ubuntu
< no output >

But when sourced, this program redefines the which command so that tagged images show up when a user runs which IMAGE on their system:

$ which ubuntu
bash: type: ubuntu: not found
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
ubuntu              14.04               1c9b046c2850        11 weeks ago        187.9 MB
ubuntu              latest              1c9b046c2850        11 weeks ago        187.9 MB

$ ubuntu
Found image; running it
aj@27872ecd864e:~/git/clink$

To do

Install script

Need to make the script for get.clink.tld (or whatever).

autocompletion / add to $PATH

It would be nice if image names could be autocompleted and/or found with any of which, type -a or declare -f, instead of redefining which.

Acknowledgements

Inspired by @jfrazelle / @jpetazzo bashrc.