{tic} comes with the convenience of providing YAML templates for various CI providers which remove the need of studying YAML notations of CI providers. The provided templates aim to work for most packages that use plain R code. Packages that rely on system libraries (such as GDAL, xml2) or link to other languages (such as Java) often need manual additions within the YAML file.

However, making manual changes to such prohibits users from simply updating to the latest upstream template that {tic} provides via yaml_templates() because custom user changes would be overwritten.

This often prevents users from updating to the most recent templates provided by {tic} since a manual comparison between the current template and the latest version is needed. {tic} 0.8.0 tackles this issue: The new update_yml() enables updating of templates to the latest version with user changes preserved.

Currently this only works for GitHub Actions as this provider enables the inclusion of arbitrary custom blocks. {tic} extracts these blocks, updates the template and then inserts the custom blocks at the correct position back into the updated template. What may sound easy at first is in fact a very complicated task behind the scenes: indentation needs to preserved, some providers care about order and some do not accept duplicate keys. While update_yml() supports GitHub Actions, Travis CI and Circle CI right now for custom environment variables and user blocks, the following rules need to be followed to ensure a smooth experience.

Shared Rules

  • All templates need to have an identifier and a revision date in their first two lines.
  • Comments of custom env vars may only span one line.
  • All custom env vars need to have a comment (above the actual env var) which includes the term [Custom env].

GitHub Actions & Circle CI

  • All custom blocks need to include [Custom block] in their name tag, e.g. - name: "[Custom block] Test custom user block2".
  • Custom env vars unique to a runner need to include [Custom matrix env var] in their tag, e.g. # [Custom matrix env var] test.

Travis CI

All of these tags are used by {tic} to preserve user changes and choose the right upstream template. During the process update_yml() also prints how many custom blocks and env vars were found. If you have some in your template and nothing is printed when updating, something went wrong and you should double check your template. In any case, it is recommended to review the changes to avoid unexpected CI failures.

Deviating from the templates

custom and custom-deploy templates

If you are using the custom or custom-deploy deploy template (e.g. via tic::use_ghactions_yml("custom")), tic::update_yml() will ignore the matrix part of the templates. This gives you the ability to specify your own runner config while still profiting from template updates.

The # [Custom header] tag

If you want to go even more custom, you can add # [Custom header] right below the ## revision date line. This tells update_yml() to ignore the complete header including the the env: key completely. This can be useful if you want to insert a service: block between env: and strategy or when specifying custom build triggers in on:.

Automating the update process

Updating {tic} YAML files can be automated further. We provide a GitHub Actions workflow which can be used together with tic::update_yml() to update the templates whenever there are newer upstream versions available. The workflow will create a branch, update the files and commit them and even open a pull request.

Just put this workflow next to any tic.yml file within .github/workflows/ and it will silently do its job. By default it will run over night as a CRON job. It only runs once a day and is not being executed on push or pull request events. The underlying update_yml() will match all files starting with "tic". Hence you can add multiple YAML files with {tic} support, e.g. "tic.yml" and "tic-db.yml".

Unfortunately, GitHub does not allow GHA workflow files to be updated and pushed by automatic approaches. To make this work, the user needs to pass a GitHub Personal Access Token (PAT) with “workflow” scopes. This PAT need to be added as a “secret” to the repo so that it can be used within the build. gha_add_secret() helps to automate this process. The linked workflow searches by default for a PAT secret named TIC_UPDATE when updating tic.yml.