Remove the tenant-secret association table

https://blueprints.launchpad.net/barbican/+spec/data-remove-tenant-secret-assoc

Currently all secrets stored in Barbican are indirectly associated with Keystone ‘projects’ (formerly known as ‘tenants’) via a tenant-secret association table. This association was added early in Barbican’s lifecycle, when it seemed that such an association would aid in retrieving different components of grouped secrets with different RBAC behaviors. However, recent discussions with OpenStack projects have indicated that this feature would be better implemented in a different way. Hence this association adds an additional join on selects with no benefit, and therefore should be removed.

Problem Description

Secrets in Barbican are indirectly related to Keystone ‘projects’ via a TenantSecret association table. This association is not utilized for any features in Barbican currently but was envisioned to allow multiple ‘projects’ to access the same secret with different access privileges. The team has since had numerous discussions with OpenStack projects that wish to integrate with Barbican, and access control could either be accomplished via Keystone Trusts, or else via ‘user’ and ‘project’ level policy based on metadata configured at the secret level (see blueprint at [1])

[1]https://review.openstack.org/#/c/127353/

Hence the TenantSecret association is not required for any envisioned Barbican use cases and therefore represents a wasteful join for all secret selects.

Proposed Change

This blueprint proposes removing the unused TenantSecret association.

Alternatives

None

Data model impact

The TenantSecret table would be removed, along with associated SQLAlchemy models and repository queries. This schema modification would require a non-trivial migration for zero downtime, as detailed in the ‘Work Items’ section below.

REST API impact

None

Security impact

None

Notifications & Audit Impact

None

Other end user impact

None

Performance Impact

Removing the TenantSecret association removes one join from secret-related queries, and removes Python code needed to create the SQLAlchemy TenantSecret model. Hence performance and code readability should be improved.

Other deployer impact

Migration scripts would need to be run on already existing deployments. There will be no other impact otherwise.

Developer impact

None

Implementation

Assignee(s)

Primary assignee:
john-wood-w

Work Items

The schema modification called for would need to be phased in to avoid breaking existing deployments with secrets stored using the current TenantSecret associations.

The first phase would add the new and initially nullable ‘tenant_id’ FK relationship to the secret entity, with all new secrets added setting this FK, and still adding the TenantSecret relationships (until older versions are rotated out). Secret retrievals would first attempt the simple query by FK, and fallback to the current TenantSecret join. The following mods would be needed:: * models.py: Add a ‘secrets_assoc’ relationship in the Tenant model class to the secrets model, similar to the ‘Container’ relationship. To the Secret model, add a ‘tenant_id’ FK reference similar to the Container model’s ‘tenant_id’ FK reference, but with nullable=True. * repositories.py: In the SecretRepo repository class add a query for secrets without the TenantSecret join, but on errors revert to the existing TenantSecret join query. * plugin/resources.py: Add setting the new ‘tenant_id’ FK on secrets to the ‘_save_secret()’ function. * store_crypto.py: Add setting the new ‘tenant_id’ FK on secrets to the ‘_store_secret_and_datum()’ function.

The second phase would provide an Alembic migration script to set the ‘tenant_id’ FK on all secrets that don’t already have it set. The ‘tenant_id’ FK would then be set as nullable=False.

The third phase would remove all logic related to the TenantSecret relationship. The following mods would be needed:: * models.py: Remove TenantSecret SQLAlchemy model class. * repositories.py: Remove TenantSecret joins from queries in the SecretRepo repository class. Remove the ProjectSecretRepo repository class. Remove ‘ProjectSecretRepo’ from the Repositories class. Remove the ‘get_project_secret_repository’ function. * plugin/resources.py: Remove ‘new_assoc’ lines from the ‘_save_secret()’’ function. * store_crypto.py: Remove ‘new_assoc’ lines from the ‘_store_secret_and_datum()’ function. * api/test_resources.py: Remove ‘project_secret_repo’ lines from the ‘_test_should_add_new_secret_metadata_without_payload’ test method. * test_repositories.py: Remove all ‘TenantSecret’ related lines. * test_store_crypto.py: Remove all ‘project_secret_repo’ lines.

The fourth phase would provide an Alembic migration script to remove the TenantSecret relationship from all secrets, and to then drop the TenantSecret table altogether.

Dependencies

None

Testing

The current unit tests will also be modified to have this change reflected upon them. Migration testing across the different phases would be needed, at least manually.

Documentation Impact

None

References

None