Recently, i’ve been working on a Go project that has dependencies on internal/private packages built in-house by the team, mostly to cut boilerplate or automate recurring processes. We’re using go.mod to manage this project’s dependencies. One problem i & other member of the team often encounter is the GitAction error whenever we tried to access private repository/package from inside the project, most especially in Dockerfile(s) or some simple ci checks. The solution to this problem is quite simple, even though it skipped my memory almost anytime i had to do it. This write-up is a small documentation for myself(easy future reference when i forget again :) ) and anyone out there facing similar issue.

An Example GitAction #

Below is an example of one of the many steps we have in the project’s GitAction:

# ci.yml
name: Build
on:
  push:
    branches:
      - *
  pull_request:
    branches: [*]

jobs:

  lint:
    name: Build to prevent compiler error

    # The type of runner that the job will run on
    runs-on: ubuntu-latest

    steps:
      # Setup Go
      - name: Set up Go
        uses: actions/setup-go@v2
        with:
          go-version: ^1.15

      - name: Check out code
        uses: actions/checkout@v2

      - name: Run build
        run: go build .

The above GitAction manifest is very simple, it builds a Go application to check for general compilation issues e.g unused variables or missed syntax error. Assuming the project or repository this workflow is meant for requires access to a particular private repository, you would get an error from go.mod when it tries to fetch & resolve all dependencies.

Solution & Requirement #

• Access to the target private repository - You will need a PAT - Personal Access Token to configure the authentication mechanism, as a result, you need to have at least read access to the target private repository. You can also generate the PAT in organization level settings on Github. To generate PAT, follow these steps:
  • Login to your Github account
  • Navigate to Settings -> Developers Settings -> Personal access tokens and generate a new one with necessary/minimal access.
  • Copy the newly generated PAT
• Add PAT as a Github Secret - For the value of the created PAT to be accessed from GitAction context, it needs to be added securely to Github secret. You can access Github secret by navigating to the target repository, click Settings -> Secrets on Github.

Once you’re able to generate PAT, add the lines below to the existing GitAction manifest, just before the authentication is required.

    - name: Setup credentials to access private repo
      run: git config --global url."https://${{ secrets.PAT }}:[email protected]/".insteadOf "https://github.com/"

The updated ci.yml should look like this:

# ci.yaml
name: Build
on:
  push:
    branches:
      - *
  pull_request:
    branches: [*]

jobs:

  lint:
    name: Build to prevent compiler error

    # The type of runner that the job will run on
    runs-on: ubuntu-latest

    steps:
      # Setup Go
      - name: Set up Go
        uses: actions/setup-go@v2
        with:
          go-version: ^1.15

      - name: Check out code
        uses: actions/checkout@v2

      - name: Setup credentials to access private repo
        run: git config --global url."https://${{ secrets.PAT }}:[email protected]/".insteadOf "https://github.com/"

      - name: Run build
        run: go build .

And that’s it! You should be able to authenticate with Github from GitAction context from now on. Enjoy :)