Add-on structure and function:

• Maintained by individuals as separate GitHub repositories (currently only public repositories)
• ddev get uses GitHub API to search for projects with the label ddev-get to display
• “Official” add-ons are in the ddev org and are actively maintained by an individual and have meaningful tests. ddev get --list shows “official” add-ons and ddev get --list --all shows all repos with the label.
• Mostly the work of an add-on is done by install.yaml
• An add-on can add docker-compose.*.yaml as with a service or just configuration override, or a Dockerfile.* to add features to the web container. It can add custom commands as either project-level or global commands.
• Add-ons are usually built using the ddev-addon-template, which has lots of docs about how to use it, including debugging GitHub Actions failures.
• Maintenance of add-ons is key, and the fundamental difference between the current approach and the former ddev-contrib repository.
• You can install an add-on:
  • From a local directory: ddev get ../some-add-on
  • From a release on any project (doesn’t have to have ddev-get label): ddev get owner/repo
  • From any tarball, including the source of a github repo: ddev get <https://github.com/owner/repo/tarball/main> for example. For a branch/PR use ddev get [<https://github.com/owner/repo/tarball>](<https://github.com/owner/repo/tarball>)/yourbranch - GitHub automatically creates the tarball.

Sections of the install.yaml file: see doc

Advanced topic: Environment variable and go template replacements, see doc.

Let’s look at a trivial example add-on, ddev-hello-world

• Built as a template from ddev-addon-template
• Names changed as given
• Minor test added

Automated tests are done with Bats, see Bats docs. It’s really just bash scripting with a few extra features, such as assertions.

• Run bats with bats tests or bats --verbose-run --show-output-of-passing-tests tests
• “Install from release” may not work until there’s a release, so if you’re doing a PR to an existing add-on, you may have to disable that until the feature has been included in a release.