Auto Rebuild on Package Source Change¶

If packages should be rebuild on a change of the package sources in the Git master branch, one option to do this is to run the cb-fetch service. This service periodically checks for changes in the git and creates package build requests under the following conditions:

Package source(s) has changed:

One ore more files of the package sources has changed. The created packaged build request is eligble to reuse an eventual existing buildroot on the selected runner

Package source(s) and/or metadata has changed:

Similar to the first case with the difference that a change on the package metadata cb/cloud_builder.yml and/or cb/build_root.kiwi will force a cleanup and rebuild of an eventual existing buildroot on the selected runner

To start the cb-fetch service either a new instance in the cloud must be started or the control plane instance can be used. Since the control plane has no hard job to perform it’s fairly fine to use it as source control service as well.

The following steps needs to be done run cb-fetch on the control plane:

Login to the control plane

See Create and Install the Control Plane for details
Configure the fetcher update intervall
```
sudo vi /etc/cloud_builder

CB_UPDATE=30
```
Change or keep the default value of 30 seconds as you see fit.
Start cb-fetch service
```
sudo systemctl start cb-fetch
```

To read the actions taken by the cb-fetch service one can watch on the Cloud Builder info response messages as follows:

cb-ctl cb-ctl --watch \
    --filter-service-name cb-fetch \
    --timeout 200

In case cb-fetch created a new package build request, information like in the following example will be provided:

{
    "identity": "CBFetch:18.193.45.127:15259:xclock",
    "message": "Package update request scheduled",
    "project": "projects/MS/xclock",
    "request_id": "d309d5d2-f2e0-11eb-9538-06be1098538e",
    "response_code": "package rebuild due to source change",
    "schema_version": 0.2,
    "target": {
        "arch": "x86_64",
        "dist": "TW"
    }
}

The provided request_id can be used to check on the status of the package build process as follows:

cb-ctl cb-ctl --watch \
    --filter-request-id d309d5d2-f2e0-11eb-9538-06be1098538e \
    --timeout 5