Use a service account with the ability to push to GCR and [configure access control](https://cloud.google.com/container-registry/docs/access-control).
Then create and download the JSON key for this service account and save content of `.json` file
[as a secret](https://docs.github.com/en/actions/configuring-and-managing-workflows/creating-and-storing-encrypted-secrets#creating-encrypted-secrets-for-a-repository)
called `GCR_JSON_KEY` in your GitHub repo. Ensure you set the username to `_json_key`.
```yaml
name: ci
on:
push:
branches: master
jobs:
login:
runs-on: ubuntu-latest
steps:
-
name: Checkout
uses: actions/checkout@v2
-
name: Login to GCR
uses: crazy-max/ghaction-docker-login@v1
with:
registry: gcr.io
username: _json_key
password: ${{ secrets.GCR_JSON_KEY }}
```
### AWS Elastic Container Registry (ECR)
Use an IAM user with the [ability to push to ECR](https://docs.aws.amazon.com/AmazonECR/latest/userguide/ecr_managed_policies.html).
Then create and download access keys and save `AWS_ACCESS_KEY_ID` and `AWS_SECRET_ACCESS_KEY` [as secrets](https://docs.github.com/en/actions/configuring-and-managing-workflows/creating-and-storing-encrypted-secrets#creating-encrypted-secrets-for-a-repository)