Go Modules with Private Git Repositories
Modules have greatly improved the dependency management process in Go. If you are new to Go Modules, and you would like to read more about how to get started, check out the official documentation.
If you’re looking for IDE recommendations for Go, this is a good comparison:
Once everything is configured correctly, it’s pretty straightforward to include specific versions of Go packages from public repositories. One of my typical starting points might look something like this:
What if we want to extend this behavior to import Go packages from private repositories? It’s pretty simple, really: make sure your Go installation has access to the private Git repositories. But how do we do that?
Under the hood, Go is using Git to pull the specified versions of your dependencies. So, the git configuration for wherever Go is running (eg. a Docker container or your laptop) has to have the appropriate credentials to access any private repositories.
Fortunately for us, there’s a git command for that. The commands below will put an entry into your .gitconfig file that tells git to use the credential-formatted URL whenever it needs to access the standard URL. For these we’re using a personal access token instead of a password, because this will store the entries in plain text. Some good discussions about this, and alternatives, can be found on this Stack Overflow question.
Your auth token must be url-encoded!
The following gists are formatted on separate lines to attempt to avoid side-scrolling:
This is great for local development, but what about my CI/CD pipeline?
I’m glad you asked! Here is an example of a Dockerfile that allows for the injection of credentials at build time:
I like to roll with docker compose, so here is an example compose file that I would use to run this Dockerfile:
Of course, Jenkins or Travis or whoever can also provide build arguments while building the Docker image, so that Go Modules can do its work without getting blocked by pesky authentication.
An Alternative — SSH
Another way to set this up would be to use your SSH key to connect, and set your .gitconfig like the following to ensure that SSH is used each time:
I, personally, found this setup to be slightly more difficult to debug when I ran into an issue, so I prefer to use the auth token URL.
Another Alternative — netrc
[added in response to the insightful comment by https://medium.com/@ysamlan]
I originally omitted this alternative, which was pointed out in this comment about using netrc with go modules:
Thanks for reading, I hope this helps on your Go Modules journey. Please let me know if I can make this post better or more complete.