podman/contrib/cirrus

Cirrus-CI

Similar to other integrated github CI/CD services, Cirrus utilizes a simple YAML-based configuration/description file: .cirrus.yml. Ref: https://cirrus-ci.org/

Workflow

All tasks execute in parallel, unless there are conditions or dependencies which alter this behavior. Within each task, each script executes in sequence, so long as any previous script exited successfully. The overall state of each task (pass or fail) is set based on the exit status of the last script to execute.

full_vm_testing Task

1. Unconditionally, spin up one VM per matrix: image_name item defined in .cirrus.yml. Once accessible, ssh into each VM and run the following scripts.

2. setup_environment.sh: Configure root's .bash_profile for all subsequent scripts (each run in a new shell). Any distribution-specific environment variables are also defined here. For example, setting tags/flags to use compiling.

3. verify_source.sh: Perform per-distribution source verification, lint-checking, etc. This acts as a minimal gate, blocking extended use of VMs when a PR's code or commits would otherwise not be accepted. Should run for less than a minute.

4. unit_test.sh: Execute unit-testing, as defined by the Makefile. This should execute within 10-minutes, but often much faster.

5. integration_test.sh: Execute integration-testing. This is much more involved, and relies on access to external resources like container images and code from other repositories. Total execution time is capped at 2-hours (includes all the above) but this script normally completes in less than an hour.

build_vm_images Task

1. When a PR is merged ($CIRRUS_BRANCH == master), run another round of the full_vm_testing task (above).

2. After confirming the tests all pass post-merge, spin up a special VM capable of communicating with the GCE API. Once accessible, ssh into the special VM and run the following scripts.

3. setup_environment.sh: Configure root's .bash_profile for all subsequent scripts (each run in a new shell). Any distribution-specific environment variables are also defined here. For example, setting tags/flags to use compiling.

4. build_vm_images.sh: Examine the merged PR's description on github. If it contains the magic string ***CIRRUS: REBUILD IMAGES***, then continue. Otherwise display a message, take no further action, and exit successfully. This prevents production of new VM images unless they are called for, thereby saving the cost of needlessly storing them.

5. If the magic string was found, utilize the packer tool to produce new VM images. Create a new VM from each base-image, connect to them with ssh, and perform these steps as defined by the libpod_images.json file.

   1. Copy the current state of the repository into /tmp/libpod.
   2. Execute distribution-specific scripts to prepare the image for use by the full_vm_testing task (above).
   3. If successful, shut down each VM and create a new GCE Image named after the base image and the commit sha of the merge.

Note: The .cirrus.yml file must be manually updated with the new images names, then the change sent in via a secondary pull-request. This ensures that all the full_vm_testing tasks can pass with the new images, before subjecting all future PRs to them. A workflow to automate this process is described in comments at the end of the .cirrus.yml file.