Firebase storage artifacts

firebaser here

If you are using Cloud Functions, the files you're seeing are related to a recent change in how the runtime (for Node 10 and up) is built.

Cloud Functions now uses Cloud Build to create the runtime (for Node 10 and up) for your Cloud Functions. And Cloud Build in turn uses Container Registry to store those runtimes, which stores them in a new Cloud Storage bucket under your project.

For more on this, also see this entry in the Firebase pricing FAQ on Why will I need a billing account to use Node.js 10 or later for Cloud Functions for Firebase?

Also see this thread on the firebase-talk mailing list about these artifacts.

🛑 Update: some other answers suggest deleting artifacts from the Storage buckets, and even setting up lifecycle management on them to do so automatically. This leads to dangling references to those artifacts in the Container Registry, which breaks future builds.

To safely get rid of the artifacts, delete the container from the Container Registry console (it's under the gcf folder) or with a script. That will then in turn also delete the artifacts from your Storage bucket.

Since version 9.14 of the CLI, the firebase deploy process automatically cleans up its container images after a deploy. So if you upgrade to the latest version, you should no longer get additional artifacts in your storage buckets.

Adding to @yo1995's response, you can delete the artifacts in the bucket without needing to go into GCP. Staying in Firebase, you go to Storage, then "Add a Bucket". From there, you will see the option to import the gcp and artifact buckets. Next, you can delete the artifacts in the buckets accordingly.

Per some comments received, it's important not to delete the bucket. Rather, delete the artifacts in the bucket only!

Artifact Bucket Location Picture

I've consulted GCP support and here are a few things

  • Cloud Functions caused the surge in storage usage
  • Since these artifacts are not stored in the default bucket, they'll charge you even if your total bytes stored are not reaching the free tier limit
  • Remove the artifact bucket at According to the support staff

Regarding the artifacts bucket, you can actually get rid of them, as they are storing previous versions of the function. However, I do not recommend deleting the "gcf-sources..." bucket(s) , as it contains the current image, so deleting this bucket would mess up your function.

I tried to remove it in whole, and so far it is not causing trouble. I'll update if it break things later.

Edit 201118: See comment below and you might need to keep the bucket while removing all the content in it.

Adding to @yo1995
I consulted with Firebase Support and they confirmed that the artifacts bucket should not be deleted. Basically the artifacts are used to help build the final image to be stored in the "gcf-sources" bucket.

To quote them directly
"you are free to delete the contents in "XX.artifacts", but please leave the bucket untouched, it will be used in the following deployment cycles."

There might be some unintended behaviour if you delete the artifacts bucket entirely.
Also "The team is working to clean up this bucket automatically, but there are some restrictions that they need to solve before publishing the solution."

For the time being I set the bucket to auto-delete files older than 1 day old.