Can appengine files in google cloud store under the bucket asia.artifacts.../containers/images be safely deleted without causing any problems. There is already 160Gb of them after just a few years. The documentation doesn’t make clear what they are for, or why they are retained there:
# gsutil du -sh gs://asia.artifacts.<project>.appspot.com
158.04 GiB gs://asia.artifacts.<project>.appspot.com
I just want to know if I can delete them, or if I need to keep paying for the storage space.
Originally I thought these files might correspond to what can be seen on the "Google Cloud Platform" "Container Registry" "Images" "app-engine-tmp". But even if you delete almost everything under the container registry web interface, there are still thousands of really old files sit-in in this containers/images folder.
If I had to guess the reason for this ever growing pile of probably junk files. I suspect if versions are deleted through the web interface, the underlying files are not removed. Is that correct?
UPDATE: I did find this clue in the cloud build logs that occur when you deploy. I tested out deleting the artifacts bucket on a test project. The project still works, and builds still works. An apparently harmless error message appears in the logs. Perhaps its genuinely safe to delete this artefacts folder. However, it'd be good to have clarity on what these ancient (apparently unused) artefact bucket files are for before deleting.
2021/01/15 11:27:40 Copying from asia.gcr.io/<project>/app-engine-tmp/build-cache/ttl-7d/default/buildpack-cache:latest to asia.gcr.io/sis-au/app-engine-tmp/build-cache/ttl-7d/default/buildpack-cache:f650fd29-3e4e-4448-a388-c19b1d1b8e04
2021/01/15 11:27:42 failed to copy image: GET https://storage.googleapis.com/asia.artifacts.<project>.appspot.com/containers/images/sha256:ca16b83ba5519122d24ee7d343f1f717f8b90c3152d539800dafa05b7fcc20e9?access_token=REDACTED: unsupported status code 404; body: <?xml version='1.0' encoding='UTF-8'?><Error><Code>NoSuchKey</Code><Message>The specified key does not exist.</Message><Details>No such object: asia.artifacts.<project>.appspot.com/containers/images/sha256:ca16b83ba5519122d24ee7d343f1f717f8b90c3152d539800dafa05b7fcc20e9</Details></Error>
Unable to tag previous cache image. This is expected for new or infrequent deployments.
It should be safe to delete those. According to Google docs:
Each time you deploy a new version, a container image is created using the Cloud Build service. That container image then runs in the App Engine standard environment. Built container images are stored in the app-engine folder in Container Registry. You can download these images to keep or run elsewhere. Once deployment is complete, App Engine no longer needs the container images. Note that they are not automatically deleted, so to avoid reaching your storage quota, you can safely delete any images you don't need.
Also as a suggestion, if you don't want to manually delete the images just in case they start piling up again, you can set up Lifecycle Management on your "artifacts" bucket and add a rule to delete old files (for example, 30 days).
This thread is similar to your concern and they have great answers. Feel fee to check it out!
IMPORTANT UPDATE: This answer only applies on Standard environment. The artifacts bucket is used as the backing storage for Flex apps images. It's used when bringing up and autoscaling VMs, so be careful when you consider deleting them.