[CORE-15194] schema_registry: add GET /schemas/ids/{id}/schema endpoint by nguyen-andrew · Pull Request #29539 · redpanda-data/redpanda

nguyen-andrew · 2026-02-05T00:51:48Z

NOTE: This PR stacks on top of #29451. Please only review the last 3 commits.

Implement the GET /schemas/ids/{id}/schema endpoint that returns the raw schema string.

The endpoint supports the following parameters:

Required id path parameter for the schema ID
Optional subject query parameter for context-aware lookup & subject filtering
Optional format query parameter for output format control

Backports Required

Release Notes

none

Update context_subject::from_string to handle context-only strings.

Rename is_default_context() to is_default_context_only() to better reflect its behavior: it returns true only when the context is the default context AND the subject is empty (context-only). Add a new method is_non_default_context() that checks if a subject is in a non-default context. This will be used in future changes to handle subject query parameters.

This enables retrieving subjects filtered by a specific context.

Copilot

Pull request overview

This PR implements the GET /schemas/ids/{id}/schema endpoint that returns raw schema strings, extending the existing GET /schemas/ids/{id} endpoint. The new endpoint supports context-aware lookups via an optional subject query parameter and output format control via a format parameter.

Changes:

Added new /schema endpoint that returns only the schema string without metadata wrapper
Enhanced both endpoints to support optional subject query parameter for context-aware schema resolution
Implemented cross-context search logic that falls back across contexts when subject is unqualified
Added comprehensive authorization tests for context-qualified subjects

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
tests/rptest/tests/schema_registry_test.py	Added test helpers and comprehensive tests for subject parameter handling and new /schema endpoint
src/v/pandaproxy/schema_registry/types.h	Renamed method and added helper for context checking
src/v/pandaproxy/schema_registry/types.cc	Fixed parsing logic to handle context-only qualified subjects
src/v/pandaproxy/schema_registry/test/context_subject.cc	Updated tests for corrected context-only parsing behavior
src/v/pandaproxy/schema_registry/store.h	Added method to retrieve subjects for a specific context
src/v/pandaproxy/schema_registry/sharded_store.h	Added sharded store interface for context-specific subject retrieval
src/v/pandaproxy/schema_registry/sharded_store.cc	Implemented sharded subject retrieval for specific contexts
src/v/pandaproxy/schema_registry/service.cc	Registered new /schema endpoint in route table
src/v/pandaproxy/schema_registry/seq_writer.cc	Updated calls to renamed is_default_context_only method
src/v/pandaproxy/schema_registry/handlers.h	Added handler declaration for new /schema endpoint
src/v/pandaproxy/schema_registry/handlers.cc	Implemented schema resolution logic and new endpoint handler
src/v/pandaproxy/api/api-doc/schema_registry.json	Added API documentation for new endpoint and subject parameter

Copilot · 2026-02-05T00:52:53Z

tests/rptest/tests/schema_registry_test.py

+        ctx1_only_id = result.json()["id"]  # ID 3 in ctx1, no ID 3 in default
+
+        # === Test: Subject portion empty (sub().empty()) ===
+        self.logger.info("Testing: Subject portion empty")


Corrected spelling of 'Retrurns' to 'Returns' in comment at line 201 of src/v/pandaproxy/schema_registry/types.h

Copilot · 2026-02-05T00:52:53Z

src/v/pandaproxy/schema_registry/handlers.cc

+    if (ctx_sub.ctx == default_context && !ctx_sub.sub().empty()) {
+        vlog(
+          srlog.error,
+          "resolve_schema_id_simple cannot be called with default context "
+          "and non-empty subject");
+        throw exception(error_code::internal_server_error);
+    }


The validation logic that prevents calling resolve_schema_id_simple with default context and non-empty subject duplicates the same check in resolve_schema_id_extended (lines 238-243). Consider extracting this validation into a helper function or document why this constraint exists in both functions.

Copilot · 2026-02-05T00:52:53Z

src/v/pandaproxy/schema_registry/handlers.cc

+    auto [resp, type, refs, meta] = std::move(def).destructure();
+    log_response(*rq.req, resp);
+    rp.rep->write_body("json", ppj::as_body_writer(std::move(resp)()));


The destructured variables type, refs, and meta are unused after destructuring. Consider using structured bindings with [[maybe_unused]] attributes or only destructure the needed resp variable to make the intent clearer.

Copilot · 2026-02-05T00:52:53Z

tests/rptest/tests/schema_registry_test.py

+class SchemaRegistryAclAuthzTestBase(SchemaRegistryEndpoints):
    """
-    Verify that schema registry endpoints are protected by the correct ACL resource and operation.
+    Base class providing shared ACL test infrastructure (setup, helpers) without test methods.


The docstring should clarify that this base class was extracted to enable test reuse with different configurations (specifically for context authorization tests), not just that it lacks test methods.

Suggested change

Base class providing shared ACL test infrastructure (setup, helpers) without test methods.

Base class extracted to share schema registry ACL / context-authorization

test infrastructure (common setup, helpers) across multiple concrete

test classes with different Redpanda and schema registry configurations.

This class intentionally defines no test methods; subclasses provide the

actual tests while reusing the common authorization setup.

Previously, the GET /schemas/ids/{id} endpoint resolved schemas using only the numeric ID without any context or subject scoping. This meant clients could not target a specific context when retrieving a schema. This change adds support for an optional `subject` query parameter, parsed via context_subject::from_string(), that controls how the schema ID is resolved: - Default context with subject (e.g., "subj" or ":.:subj"): perform an extended search: default context with subject first, then other contexts with subject, then default context without the subject restriction - All other cases: resolve within a single context only The schema definition is now retrieved using the resolved context, ensuring the correct schema is returned in multi-context deployments.

Add test for the `subject` query parameter on GET /schemas/ids/{id}, verifying that it correctly extracts context for schema lookup. Also update the test client to support the new parameter.

Extract shared ACL test infrastructure (setup, helpers) into a new SchemaRegistryAclAuthzTestBase class to enable reuse by other tests.

Add SchemaRegistryContextAuthzTest to verify ACL enforcement when using context-qualified subjects and the subject query parameter with GET /schemas/ids/{id}. The tests cover authorization scenarios including literal and prefix ACLs on context-qualified subjects, cross-context search behavior, and proper 403 responses to prevent information leakage.

…{id}

Add OpenAPI documentation for the raw schema retrieval endpoint, including the optional subject and format query parameters.

Add handler for the raw schema retrieval endpoint, supporting optional subject query parameter for context-aware schema lookup.

Add test client method and integration test verifying the raw schema endpoint returns the same schema as GET /schemas/ids/{id}["schema"].

nguyen-andrew · 2026-02-05T10:05:42Z

Force push to rebase on latest base branch.

vbotbuildovich · 2026-02-05T11:48:40Z

Retry command for Build#80199

please wait until all jobs are finished before running the slash command

/ci-repeat 1
skip-redpanda-build
skip-units
skip-rebase
tests/rptest/tests/quota_management_test.py::QuotaManagementUpgradeTest.test_upgrade

vbotbuildovich · 2026-02-05T11:57:57Z

CI test results

test results on build#80199

test_class	test_method	test_arguments	test_kind	job_url	test_status	passed	reason	test_history
QuotaManagementUpgradeTest	test_upgrade	null	integration	https://buildkite.com/redpanda/redpanda/builds/80199#019c2d54-0c7e-4ad1-8409-eac974960446	FLAKY	15/21	Test FAILS after retries.Significant increase in flaky rate(baseline=0.0623, p0=0.0066, reject_threshold=0.0100)	https://redpanda.metabaseapp.com/dashboard/87-tests?tab=142-dt-individual-test-history&test_class=QuotaManagementUpgradeTest&test_method=test_upgrade

pgellert

This looks good to go. Not approving yet just to wait for the base PR to merge.

nguyen-andrew added 3 commits February 4, 2026 23:31

sr/types: Update context_subject::from_string

ea3b809

Update context_subject::from_string to handle context-only strings.

schema_registry: add context-specific get_subjects overload

c24181f

This enables retrieving subjects filtered by a specific context.

nguyen-andrew requested a review from pgellert February 5, 2026 00:51

nguyen-andrew self-assigned this Feb 5, 2026

nguyen-andrew requested a review from a team as a code owner February 5, 2026 00:51

Copilot AI review requested due to automatic review settings February 5, 2026 00:51

github-actions bot added the area/redpanda label Feb 5, 2026

Copilot AI reviewed Feb 5, 2026

View reviewed changes

nguyen-andrew added 8 commits February 5, 2026 09:59

schema_registry/dt: test context lookup via subject param

07eb0f6

Add test for the `subject` query parameter on GET /schemas/ids/{id}, verifying that it correctly extracts context for schema lookup. Also update the test client to support the new parameter.

schema_registry/dt: extract base class from ACL authz test

cbff3df

Extract shared ACL test infrastructure (setup, helpers) into a new SchemaRegistryAclAuthzTestBase class to enable reuse by other tests.

schema_registry/swagger: document subject param for GET /schemas/ids/…

0596bc4

…{id}

schema_registry/swagger: document GET /schemas/ids/{id}/schema endpoint

d1688b0

Add OpenAPI documentation for the raw schema retrieval endpoint, including the optional subject and format query parameters.

schema_registry: implement GET /schemas/ids/{id}/schema handler

f85d1c8

Add handler for the raw schema retrieval endpoint, supporting optional subject query parameter for context-aware schema lookup.

schema_registry/dt: test GET /schemas/ids/{id}/schema endpoint

35d4892

Add test client method and integration test verifying the raw schema endpoint returns the same schema as GET /schemas/ids/{id}["schema"].

nguyen-andrew force-pushed the sr/subject-query-param-schemas branch from f63edbe to 35d4892 Compare February 5, 2026 10:05

nguyen-andrew mentioned this pull request Feb 5, 2026

[CORE-15194] schema_registry: add GET /schemas/ids/{id}/versions endpoint #29544

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[CORE-15194] schema_registry: add GET /schemas/ids/{id}/schema endpoint#29539

[CORE-15194] schema_registry: add GET /schemas/ids/{id}/schema endpoint#29539
nguyen-andrew wants to merge 11 commits intoredpanda-data:devfrom
nguyen-andrew:sr/subject-query-param-schemas

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-    Base class providing shared ACL test infrastructure (setup, helpers) without test methods.
+    Base class extracted to share schema registry ACL / context-authorization
+    test infrastructure (common setup, helpers) across multiple concrete
+    test classes with different Redpanda and schema registry configurations.
+    This class intentionally defines no test methods; subclasses provide the
+    actual tests while reusing the common authorization setup.

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nguyen-andrew commented Feb 5, 2026

Backports Required

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nguyen-andrew commented Feb 5, 2026

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vbotbuildovich commented Feb 5, 2026

Retry command for Build#80199

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