* Add OpenAPI 3.2 specification generation for Prometheus HTTP API
This commit introduces an OpenAPI specification for the Prometheus API.
After testing multiple code-generation servers with built-in APIs, this
implementation uses an independent spec file outside of the critical path.
This spec file is tested with a framework present in this pull request.
The specification helps clients know which parameters they can use and is
served at /api/v1/openapi.yaml. The spec file will evolve with the
Prometheus API and has the same version number.
Downstream projects can tune the APIs presented in the spec file with
configuration options using the IncludePaths setting for path filtering.
In the future, there is room to generate a server from this spec file
(e.g. with interfaces), but this is out of scope for this pull request.
Architecture:
- Core OpenAPI infrastructure (openapi.go): Dynamic spec building,
caching, and thread-safe spec generation
- Schema definitions (openapi_schemas.go): Complete type definitions
for all API request and response types
- Path specifications (openapi_paths.go): Endpoint definitions with
parameters, request bodies, and response schemas
- Examples (openapi_examples.go): Realistic request/response examples
- Helper functions (openapi_helpers.go): Reusable builders for common
OpenAPI structures
Testing:
- Comprehensive test suite with golden file validation
- Test helpers package for API testing infrastructure
- OpenAPI compliance validation utilities
The golden file captures the complete specification for snapshot testing.
Update with: go test -run TestOpenAPIGolden -update-openapi-spec
REVIEWERS: The most important thing to check would be the OpenAPI golden
file (web/api/v1/testdata/openapi_golden.yaml). Test scenarios are important
as they test the actual OpenAPI spec validity.
Signed-off-by: Julien Pivotto <291750+roidelapluie@users.noreply.github.com>
* Add OpenAPI 3.1 support with version selection
Add support for both OpenAPI 3.1 and 3.2 specifications with version
selection via openapi_version query parameter. Defaults to 3.1 for
broader compatibility
Signed-off-by: Julien Pivotto <291750+roidelapluie@users.noreply.github.com>
* Enhance OpenAPI examples and add helper functions
- Add timestampExamples helper for consistent time formatting
- Add exampleMap helper to simplify example creation
- Improve example summaries with query details
- Add matrix result example for range vector queries
Signed-off-by: Julien Pivotto <291750+roidelapluie@users.noreply.github.com>
* web/api: Add AtST method to test helper iterators
Implement the AtST() method required by chunkenc.Iterator interface
for FakeSeriesIterator and FakeHistogramSeriesIterator test helpers.
The method returns 0 as these test helpers don't use start timestamps
Signed-off-by: Julien Pivotto <291750+roidelapluie@users.noreply.github.com>
* OpenAPI: Add minimum coverage test
Signed-off-by: Julien Pivotto <291750+roidelapluie@users.noreply.github.com>
* OpenAPI: Improve examples handling
Signed-off-by: Julien Pivotto <291750+roidelapluie@users.noreply.github.com>
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Signed-off-by: Julien Pivotto <291750+roidelapluie@users.noreply.github.com>
Update go.work from go 1.24.9 to go 1.24.0 to match the version
specified in all go.mod files across the project
Signed-off-by: Julien Pivotto <291750+roidelapluie@users.noreply.github.com>
This allows nested modules to reference the root prometheus/prometheus
module from the local filesystem instead of downloading versioned
releases. Improves development workflow and ensures CI tests against
current code.
Signed-off-by: Julien Pivotto <291750+roidelapluie@users.noreply.github.com>
