How to "docker-compose build" a service from code located in local git repository?

Question

I have a git repository placed in local file system at /home/nou/code/lib.git Also I have /home/nou/docker-compose.yaml that is used to deploy a service based on the code from the repo:

version: '2'
services:
  lib:
    container_name: lib
    build: git://./code/lib.git/
    #build: git://./code/lib.git
    #build: git:///home/nou/code/lib.git/
    #build: git://file:///home/nou/code/lib.git/

As you can see, am trying to build lib service from the local git repo, but the only result I observe is such error (or similar):

nou@ubuntu:~/$ docker-compose build
Building lib
ERROR: error fetching: fatal: unable to connect to .:
.: No address associated with hostname

: exit status 128

How can I use local git repo to build services using docker-compose?

Solution 1

What you are specifically after (building from a bare repository on a local filesystem) isn't functionality offered by Docker, and by extension, docker-compose. Docker supports building from a few different URLs, but not bare repositories on local filesystems. You can try a few workarounds:

• Build straight from Github: docker build https://github.com/docker/rootfs.git
• Run a Git daemon to use the git:// protocol: git daemon --base-path=. --export-all (in /home/nou/code)
• Running a Git daemon from within Docker, mounting your bare repository as a volume and building inside it via a mounted Docker socket
• Converting your bare repository to a normal one

https://docs.docker.com/engine/reference/commandline/build/#build-with-url

Solution 2

You can try this, it works for me:

1. Create a user named "git"

   $ sudo adduser git
   $ su git
   $ cd ~
   $ mkdir .ssh && chmod 700 .ssh
   $ touch .ssh/authorized_keys && chmod 600 .ssh/authorized_keys
   

2. If you don't have ssh keys for "nou" user then, from "nou" user run

   $ ssh-keygen
   

   and accept all defaults.

3. Add "nou" user's ssh public key to git user ~/.ssh/authorized_keys

   $ sudo cat nou_user_home/.ssh/id_rsa.pub >> git_user_home/.ssh/authorized_keys
   

After this try below command from "nou" user:

docker build git@localhost:/home/nou/code/lib.git

If Dockerfile is not at the root of cloned repository then:

docker build -f folder_containing_dockerfile/Dockerfile 
git@localhost:/home/nou/code/lib.git

If this all works fine then you can try with your docker-compose file.

Comments

[luac]

Awesome answer, thank you. Git daemon works for me.(My current workaround is to clone into temporary directory and remove it after docker-compose goes down)

[luac]

Sad to say, but docker can't clone daemon-hosted git://localhost/lib.git due to dumb git bad pack header error. At the same time I can clone it using git clone...

[user2640621]

I've updated the command for git daemon to properly export your repository, you should be able to docker build git://localhost/lib.git after starting the daemon with the updated command.