GitHub Actions throws Git Error when npm installing private GitHub repo - node.js

Question

I have an GitHub Repo with some testing workflows:
name: Tests the App
on:
push:
branches: [main]
jobs:
test:
runs-on: ubuntu-latest
strategy:
matrix:
node-version: [16.x]
steps:
- uses: actions/checkout#v2
- name: Use Node.js ${{ matrix.node-version }}
uses: actions/setup-node#v2
with:
node-version: ${{ matrix.node-version }}
cache: "npm"
- run: echo "Testing App."
- run: npm install
- run: echo "Using ESLint."
- run: npm run lint
- run: echo "Testing App."
- run: npm run test
- run: echo "Test completed!"
Unfortunately it throws an git error with exit code 128:
npm ERR! code 128
npm ERR! An unknown git error occurred
npm ERR! command git --no-replace-objects ls-remote ssh://git#github.com/MYNAME/REPONAME.git
npm ERR! Warning: Permanently added the RSA host key for IP address 'SOMEIPADDR' to the list of known hosts.
npm ERR! git#github.com: Permission denied (publickey).
npm ERR! fatal: Could not read from remote repository.
npm ERR!
npm ERR! Please make sure you have the correct access rights
npm ERR! and the repository exists.
[…]
Error: Process completed with exit code 128.
When it tries to npm install the dependencies there is a private GitHub Repo REPONAME which needs to be installed from my account.
"dependencies": {
"pckgname": "git+ssh://git#github.com:MYNAME/REPONAME.git#main"
}
What's the best way to make this work in ci/cd environments?

Answer 1

You could use webfactory/ssh-agent#v0.5.3. First thing you would do is create an SSH key pair in the REPONAME.git repository, (preferably dedicated for Github actions), then put the private key as a secret in Github Actions, for this example we'll call it SSH_PRIVATE_KEY, then simply update your workflow like this:
steps:
- uses: actions/checkout#v2
- uses: webfactory/ssh-agent#v0.5.3
with:
ssh-private-key: ${{ secrets.SSH_PRIVATE_KEY }}
- ...
Further details on this action here.