netbox-docker/DOCKER_HUB.md

cloud.docker.com Configuration

The automatic build is configured in cloud.docker.com.

The following build configuration is expected:

Source Repository: github.com/netbox-community/netbox-docker
Build Location: Build on Docker Hub's infrastructure
Autotest: Internal and External Pull Requests
Repository Links: Enable for Base Image
Build Rules:
- Source Type: Branch
  Source: master
  Docker Tag: branches
  Dockerfile location: Dockerfile
- Source Type: Branch
  Source: master
  Docker Tag: prerelease
  Dockerfile location: Dockerfile
- Source Type: Branch
  Source: master
  Docker Tag: release
  Dockerfile location: Dockerfile
Build Environment Variables:
# Create an app on Github and use it's OATH credentials here
- Key: GITHUB_OAUTH_CLIENT_ID
  Value: <secret>
- Key: GITHUB_OAUTH_CLIENT_SECRET
  Value: <secret>
Build Triggers:
- Name: Cron Trigger
# Use this trigger in combination with e.g. https://cron-job.org in order to regularly schedule builds

Background Knowledge

The build system of cloud.docker.com is not made for this kind of project. But we found a way to make it work, and this is how:

1. The docker hub build system allows to overwrite the scripts that get executed for build, test and push. See /hooks/*.
2. Shared functionality of the scripts build, test and push is extracted to /hooks/common.
3. The build script runs run_build() from /hooks/common. This triggers either /build-branches.sh, /build-latest.sh or directly /build.sh.
4. The test script just invokes docker-compose commands.
5. The push script runs run_build() from hooks/common with a --push-only flag. This causes the build.sh script to not re-build the Docker image, but just the just built image.

The Docker Tag configuration setting ($DOCKER_TAG) is only used to select the type (release, prerelease, branches) of the build in hooks/common. Because it has a different meaning in all the other build scripts, it is unset after it has served it's purpose.