feat: Add relation for s3 interface on the provider side

[mvlassis]

Summary

• Add chisme component for the s3 interface, using the object-storage-charmlib library from https://github.com/canonical/object-storage-integrator`. Note that we will only use this here, so we don't have any reason to put this to chisme.
• Add unit tests:
  • For the new relation
  • For _get_minio_endpoint
• Note that we don't add any integration tests, since they currently don't test any integrations via the object-storage, we usually test them on the requirer side, see https://github.com/canonical/argo-operators

Testing

Since this relation will be mostly used to connect via the gateway mode, I tested the following manually:

• Pack and deploy this version of minio
• Configure with my Azure account via gateway mode:

juju config minio \
    mode=gateway \
    gateway-storage-service=azure \
    access-key=<azurestorageaccountname> \
    secret-key=<azurestorageaccountkey>

• Deploy this version of argo
• Integrate them and run a sample workflow
• Ensure that the artifacts show properly in the Azure UI

Closes #299

[ckfbot]

🤖 Backport labels populated

Labels to this pull request were added automatically by the populate-labels.yaml action.

When the PR is merged, backport PRs according to the labels will be automatically created. To skip the backport creation, remove any unneeded labels before merging the PR.

[Copilot]

Pull request overview

This PR adds provider-side support for the s3 interface to the MinIO charm, publishing S3 connection details to related requirer applications via a new Chisme component.

Changes:

• Added S3ProviderComponent (using object-storage-charmlib) to serve s3-credentials relation data (endpoint, access key, secret key).
• Added _get_minio_endpoint() helper and unit tests covering endpoint construction and relation data publication.
• Fixed a typo in integration test function names (test_metrics_enpoint → test_metrics_endpoint).

Reviewed changes

Copilot reviewed 7 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/components/s3_provider_component.py	New provider component that publishes S3 connection info via the s3 interface.
src/charm.py	Wires the new S3 provider component and adds _get_minio_endpoint() helper.
metadata.yaml	Declares the new s3-credentials provided relation using interface s3.
pyproject.toml	Adds object-storage-charmlib dependency for charm runtime.
tests/unit/test_charm.py	Adds unit tests for _get_minio_endpoint() and s3-credentials relation data.
tests/integration/test_charm.py	Fixes test function naming typo.
tests/integration/test_charm_ambient.py	Fixes test function naming typo.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

Pull request overview

Copilot reviewed 7 out of 8 changed files in this pull request and generated no new comments.

[theoctober19th]

Thanks for adding me as a reviewer! I have only one question -- in the context of this charm, is it not necessary/required that this charm provides with the requirer with region, bucket, path, etc.?

Also, according to the s3 interface specification, we allow requirers to also send a custom param bucket and path in the relation data when the relation is joined. Are these info sent by requirers simply not relevant here?

[NohaIhab]

thanks @mvlassis, a couple comments