Add Backblaze B2 artifact store flavor

[goanpeca]

Describe changes

Implemented #4786 Add Backblaze B2 artifact store flavor and documentation.

Pre-requisites

Please ensure you have done the following:

• I have read the CONTRIBUTING.md document.
• I have added tests to cover my changes.
• I have based my new branch on develop and the open PR is targeting develop. If your branch wasn't based on develop read Contribution guide on rebasing branch to develop.
• IMPORTANT: I made sure that my changes are reflected properly in the following resources:
  • ZenML Docs
  • Dashboard: Needs to be communicated to the frontend team.
  • Templates: Might need adjustments (that are not reflected in the template tests) in case of non-breaking changes and deprecations.
  • Projects: Depending on the version dependencies, different projects might get affected.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Other (add details above)

[CLAassistant]

All committers have signed the CLA.

[bcdurak]

hey @goanpeca, is the PR ready for review? or is it in the draft stage?

[Copilot]

Pull request overview

Adds a new b2 integration that provides a Backblaze B2 artifact store flavor by subclassing the existing S3 artifact store implementation, plus unit tests and documentation for users to configure B2 via its S3-compatible API.

Changes:

• Introduce zenml.integrations.b2 with a b2 artifact store flavor/config that injects a default B2 S3 endpoint and supports B2-specific credential env vars.
• Add a thin B2 artifact store subclass to ensure config_kwargs are applied consistently to both s3fs and the boto3.resource path.
• Add docs page + TOC entry and unit tests for the new flavor/config behavior.

Reviewed changes

Copilot reviewed 22 out of 23 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
tests/unit/integrations/b2/test_b2_artifact_store_flavor.py	Adds unit tests for the B2 flavor/config defaults and env var credential mapping.
tests/unit/integrations/b2/init.py	Marks the new unit-test package.
src/zenml/integrations/constants.py	Registers the b2 integration constant.
src/zenml/integrations/b2/flavors/b2_artifact_store_flavor.py	Implements B2 flavor + config defaults (endpoint, env var creds, config kwargs).
src/zenml/integrations/b2/flavors/init.py	Exposes the B2 flavor/config exports.
src/zenml/integrations/b2/artifact_stores/b2_artifact_store.py	Adds the B2 artifact store implementation (S3 subclass + boto3 config handling).
src/zenml/integrations/b2/artifact_stores/init.py	Exposes the B2 artifact store export.
src/zenml/integrations/b2/init.py	Declares the B2Integration and its requirements/flavors.
docs/book/component-guide/toc.md	Adds Backblaze B2 to the component guide TOC.
docs/book/component-guide/artifact-stores/backblaze.md	Adds user-facing documentation for configuring and using the B2 artifact store flavor.

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[goanpeca]

Hi @bcdurak thanks for the ping, I think we are good to review, however I will need to have the remaining CI tests that need approval to run to see if I need to fix something. I could not test all locally.

Thanks!

[goanpeca]

Hi @bcdurak I think none of the previous failing tests were related to this PR, I rebased the branch with latest develop and made a push. Ready for review

Thanks!

[bcdurak]

Thanks @goanpeca, you are right. Our CI had some errors unrelated to this PR. They should already be fixed now. We will try to take a look as soon as possible. 👍

[github-actions]

⚠️ This PR has been inactive for 2 weeks and has been marked as stale.
Timeline:

• Week 2 (now): First reminder - PR marked as stale
• Week 4: PR will be automatically closed if no activity
  Please update this PR or leave a comment to keep it active. Any activity will reset the timer and remove the stale label.

[goanpeca]

Updated to the latest develop.