starrocks/fe/fe-spi/README.md

StarRocks FE SPI (Service Provider Interface)

The fe/spi module defines the public Service Provider Interfaces (SPIs) for the StarRocks Frontend. It is the foundation of the pluggable architecture: connectors and plugins must implement these contracts, while the FE core programs against the interfaces.

Responsibilities

• Provide stable, minimal contracts for connectors and plugins.
• Decouple FE core from concrete implementations.
• Enable safe evolution via versioning and deprecation policies.

Design goals

• Stability first: interfaces evolve conservatively and compatibly.
• Clear separation: SPI must not depend on FE core internal types.
• Minimal surface: small, orthogonal interfaces; no hidden coupling.
• Testability: interfaces are mock-friendly and deterministic.

What lives here

• Public Java interfaces and data contracts for plugin authors.
• Common exceptions, result/status types intended for SPI boundaries.
• Documentation and guidance for implementers.

Typical extension points

• Connectors (external catalogs, metadata/external table access, etc.)
• Resource and system integrations (e.g., external services)
• Administrative or management hooks exposed via well-defined SPI

How FE core uses SPI

• FE core depends only on SPI interfaces.
• Concrete plugins/connectors are discovered and wired at runtime.
• Implementations must be prepared for concurrent use by FE subsystems.

Testing guidance

• Unit test against SPI interfaces with mocks/fakes.
• Add integration tests that exercise real interactions where applicable.
• Include negative tests for error paths and boundary conditions.

References

• Architecture overview: see project root README and FE module docs
• Testing structure: test/sql/, fe/fe-core/src/test/
• StarRocks documentation: https://docs.starrocks.io/