Iceberg REST Phase 1 [3/3]: Client and integration validation

[cbb330]

Summary

Part 3 of 3 for a read-only Iceberg REST Catalog facade.

This PR validates the facade with stock Iceberg clients. It does not change runtime behavior. Java RESTCatalog round-trips, a PyIceberg smoke test, and CI wiring live here; unit coverage for the facade is in #499.

Changes

• Client-facing API Changes
• Internal API Changes
• Bug Fixes
• New Features
• Performance Improvements
• Code Style
• Refactoring
• Documentation
• Tests

Tests

IcebergRestCatalogRoundTripTest creates tables through the existing OpenHouse API and reads them through Iceberg's RESTCatalog:

• Config advertises only the three implemented table operations.
• List tables: namespace isolation, empty namespaces, and opaque pageToken / pageSize pagination.
• Load table: schema, field IDs, required/optional fields, partition spec, sort order, location, and properties.
• HEAD existence for present, missing, and wrong-namespace tables.
• Missing tables and namespaces raise Iceberg NoSuchTableException.
• Invalid prefixes return 400; snapshots=refs returns 501.
• Existing OpenHouse GET /v1/databases/{db}/tables/{table} still works.
• Table loads retain existing read audit attribution and increment http.server.requests.

CI:

• integrations/python/dataloader/scripts/iceberg_rest_catalog_smoke.py creates a table via OpenHouse and reads it with PyIceberg RestCatalog.
• .github/workflows/build-run-tests.yml runs :services:tables:check and that smoke test against docker-compose.

This PR itself changes only those three files. The GitHub files tab against main also includes #498 and #499.

Testing Done

• Manually Tested on local docker setup. Please include commands ran, and their output.
• Added new tests for the changes made.
• Updated existing tests to reflect the changes made.
• No tests added or updated. Please explain why. If unsure, please feel free to ask for help.
• Some other form of testing like staging or soak time in production. Please explain.

Validated locally with JDK 17:

./gradlew :services:tables:check
python3 -m py_compile integrations/python/dataloader/scripts/iceberg_rest_catalog_smoke.py

The Java round-trip suite passes, including pagination, capabilities, existing-API regression, audit, and metrics checks. The Docker/PyIceberg smoke test is exercised by CI, not re-run locally for this update.

Additional Information

• Breaking Changes
• Deprecations
• Large PR broken into smaller PRs, and PR plan linked in the description.

Merge in order:

1. Iceberg REST Phase 1 [1/3]: Read-only contract and codegen #498 — Read-only contract and codegen
2. Iceberg REST Phase 1 [2/3]: Runtime facade and unit coverage #499 — Runtime facade and unit coverage
3. Iceberg REST Phase 1 [3/3]: Client and integration validation #500 — Client and integration validation ← you are here

[cbb330]

Superseded by the same-repo GitHub stack (fork heads cannot be added to GitHub stacks):

1. Iceberg REST Phase 1 [1/3]: Read-only contract and codegen #689
2. Iceberg REST Phase 1 [2/3]: Runtime facade and unit coverage #690
3. Iceberg REST Phase 1 [3/3]: Client and integration validation #691

Closing in favor of that stack.

[cbb330]

Closing in favor of stacked PRs #689 / #690 / #691.