For example, on a git push in a `source` repository, you want certain files to be pushed into a `destination` repository. A couple of examples of this could be:
* Specifying a directory in the `source` to be pushed to `destination`
* Generating some files using another GitHub Action (e.g. MarkDown to PDF) and pushing the PDFs across
* Using SSH deploy keys (recommended, a bit harder to set up): [push-to-another-repository-deploy-keys-example](https://github.com/cpina/push-to-another-repository-deploy-keys-example). The configuration is in the file [.github/workflows/ci.yml](https://github.com/cpina/push-to-another-repository-deploy-keys-example/blob/main/.github/workflows/ci.yml#L21)
* Using a Personal Access Token (first iteration, not recommended but easier to set up: [push-to-another-repository-example](https://github.com/cpina/push-to-another-repository-example). The configuration is in the file [.github/workflows/ci.yml](https://github.com/cpina/push-to-another-repository-example/blob/main/.github/workflows/ci.yml#L21)
In the above examples, the file [build.sh](https://github.com/cpina/push-to-another-repository-deploy-keys-example/blob/main/build.sh) is executed, which creates a new directory `output/` and this directory is copied across to the [destination repository](https://github.com/cpina/push-to-another-repository-output)
:warning: Please bear in mind that the files in the specified directory of the target repository are deleted unless the option `target-directory` is used (in this case, only the files for this directory are deleted).
Username/Organization of the GitHub repository that will be used for the `destination` repository. To output to a repository such as `https://github.com/cpina/push-to-another-repository-output` this variable would be `cpina`.
Name of the `destination` repository. To output to a repository such as `https://github.com/cpina/push-to-another-repository-output` this variable would be `push-to-another-repository-output`
:warning:: the GitHub Action currently deletes all the files and directories in the destination repository. The idea is to copy from an `output` directory into the `destination-repository-name`, removing all pre-existing files.
The name that will be used for the commit to the destination-repository-name. If not specified, the `destination-github-username` will be used instead.
The Username/Organization for the destination repository, if different from `destination-github-username`. For the repository `https://github.com/cpina/push-to-another-repository-output` this variable would be `cpina`.
Someone with write access to your repository or this action, could technically add code to leak the key. Thus, *it is recommended to use the SSH deploy key method to minimise the impact* if this were to happen.
This action supports both methods to keep backwards compatibility, because in the beginning it only supported the GitHub Personal Authentication token.
* In your computer terminal, generate an ssh key using: `ssh-keygen -t ed25519 -C "your_email@example.com"` (the type ed25519 is recommended by [GitHub documentation](https://docs.github.com/en/authentication/connecting-to-github-with-ssh/generating-a-new-ssh-key-and-adding-it-to-the-ssh-agent#generating-a-new-ssh-key)).
* ssh will ask for a file path: `Enter file in which to save the key`: write a new file name. I suggest the default directory and as a filename: `id_github_{name_of_your_destination_repository}` to avoid overwriting a previous file. If you will be using this action for multiple repositories, you might want to generate different keys for each one. For the repository `https://github.com/cpina/push-to-another-repository-example/`, `id_github_push-to-another-repository-example` could be used.
* Title: "GitHub Action push to another repository"
* Key: paste the contents of the file with the public key. This was generated in the "Generate the key files" step and the name is "id_github_name_of_your_repository.pub"
* Value: paste the contents of the file with the private key. This was generated in the "Generate the key files" step and the name is "id_github_name_of_your_repository"
This does not need to be done if you chose to set up the deploy keys using the steps above. This method is here for compatibility with the initial approach of this GitHub Action. The personal access token would have access to all your repositories, so if it were to be leaked, the damage would be greater (it would allow pushes to the same repositories that the Personal Access Token owner has access and other possible associated permissions). On the other hand, the setup is a bit easier because it does not involve creating the deploy key.
* Generate a new token entering a name, expiration date and choose "Repo". Click the bottom button "Generate token". If you choose an expiration date you will need to create a new token after this date. I've chosen in this example "No expiration"; this should be used carefully.
This is the most common problem. Carefully read the logs on the GitHub Action pages of the source repositories. The action tries to write the errors and gives possible solutions / hints. The first suggestion is to follow the steps above to create the ssh keys or Personal Access Token, and set it up again, but some problems that have occurred in the past are:
* User was logged in to GitHub with an account that did not have permission to push into the destination repository. The action could not push (permission denied).
Test that the Personal Access Token has the correct permissions to push to the destination repository. This can be useful to check that the Personal Access Token has not expired or has the correct permissions.
Instead of `.ssh/id_push-to-another-repository-output_ed25519`, use the file as you created it. This is the **private** key (it does not end with `.pub`). If you used the correct private key for the correctly uploaded public key, it will print something along the lines of:
This should match what you see in the deploy key of the destination repository. If it does not match, the deploy key is not properly set (perhaps different public/private keys were used, for example).
:warning: this will also copy `.github/workflows/`! The destination repository will try to execute the action. It will probably fail because the Personal Acccess Token / ssh keys will not be available for the destination repository.
A suggestion if you are using `source_directory: .` is to disable the GitHub Actions in the destination repository. To disable Actions in the destination repository:
If you need to filter files or directories (exclude files, include only some, etc.) use a step before the action to filter from a temporary directory to the directory that will be pushed. This can be done with "rsync" or any tool that you feel comfortable (could be "rclone" or "find + exec + rm", "find + exec + mv", etc. depending on your needs).
For example see the step: https://github.com/cpina/push-to-another-repository-deploy-keys-example/blob/main/.github/workflows/ci.yml#L21
In the step above it installs rsync (depending on your environment it will already be installed) and it copies everything from "output_temp" to "output" excluding "main.epub". Be careful with the usage of "/" in rsync directories or exclude parameter. Refer to the rsync documentation for other options such as filter using an extension, include only some files / directories, etc.
Please check that no space was copied by mistake to the `API_TOKEN_GITHUB`. If GitHub created a token with `#` or a space inside, I suggest creating a new one.
The problem, for those that are curious, is that the Personal Access Token is used in the git URLs and the URLs don't support `#`. The error "URL using bad/illegal format" is coming from the curl library used by git.
