linux - How to bake credential into docker image for git?

Question

This is actually a question following from my previous one.

I am trying to use docker to host a personal note-taking web service and want to backup data generated by the service (my notes). Currently I plan to use git to commit, pull, and push to a repository for my purpose.

To do git pull and push, my docker image needs to host my credentials. What is the easiest yet safe way to achieve this?

What I have done so far:

• I choose Alpine as the base image of the image of my service.
• Because I only need credentials for git, I think put a git credential helper into the image may solve my problem. I can save credentials to the helper during the build time and use them during runtime.
• I googled a while and decided to use libsecret as my git credential helper, according to this article.
• I have installed libsecret and set my git credential helper to be git-credential-libsecret

However, I cannot make git-credential-libsecret functional so far. Here are a couple of problems that I encountered:

• Firstly, I tested git-credential-libsecret get and get the following error:

  CRITICAL **: could not connect to Secret Service: Cannot spawn a message bus without a machine-id: Unable to load /var/lib/dbus/machine-id or /etc/machine-id: Failed to open file */var/lib/dbus/machine-id*: No such file or directory

  • I (probably?) solved it by installing dbus and run dbus-uuidgen > /var/lib/dbus/machine-id

• Then I try to run git-credential-libsecret get again. This time, it reports that:

  CRITICAL **: could not connect to Secret Service: Cannot autolaunch D-Bus without X11 $DISPLAY

  • I tried to install dbus-x11 and run dbus-launch --sh-syntax(from here) but with no luck this time. The error continues.

In conclusion, I would like to know:

1. Am I on a right direction (using git credential helper) to achieve my goal?
2. If so, how can I resolve the X11 problem?
3. Are there any other quick and clean methods to backup data in docker with version control?

Answer 1

If your git provider supports ssh with public keys, I think the easiest way would be to switch to them. You would also not have to copy around your password.

You need to:

• add ssh client to your docker image
• generate an ssh key and copy it to the image. The ssh-agent part is not needed
• register the key to the provider