[Swift] Swift gRPC Integration for Fory

[chaokunyang]

This issue is reserved for gsoc, do not take over it currently.

Feature Request

Swift gRPC Integration in Apache Fory

Problem Statement

Fory Swift currently lacks:

• Generated Swift transport bindings for services.
• A Fory-backed codec for grpc-swift.
• Official examples, integration tests, and comprehensive documentation for Swift gRPC.

Expected Outcomes

• Generate Swift gRPC transport code from service definitions.
• Support unary, client-streaming, server-streaming, and bidirectional-streaming RPCs.
• Provide a grpc-swift codec backed by Fory serialization and deserialization.
• Provide deterministic, safe decode behavior, including zero-copy when valid and copy fallback when required.
• Add integration tests and runnable examples.
• Provide comprehensive Swift gRPC integration documentation.

Detailed Scope

1) Service gRPC Code Generation

• Generate service.swift for service protocols and method signatures.
• Generate service_grpc.swift for grpc-swift client/server bindings.
• Ensure generated signatures align with existing Swift model types.

2) grpc-swift Codec Integration

• Implement codec encode and decode using Fory Swift runtime.
• Map request and response types to generated service APIs.
• Provide clear error mapping for invalid payloads and type mismatches.

3) Decode Path Behavior

• Add zero-copy decode path when ownership and lifetime constraints are safe.
• Add copy fallback path when zero-copy cannot be guaranteed.
• Keep behavior deterministic and memory-safe.

4) Tests

Compiler and integration tests should cover:

• Generated file names and key service signatures.
• Unary, client-streaming, server-streaming, and bidi-streaming coverage.
• Codec round-trip and error-path behavior.
• Zero-copy path and fallback path validation.

5) Examples and Comprehensive Documentation

• Add runnable Swift gRPC server and client examples using generated code and codec.
• Update compiler and Swift docs for gRPC generation and integration usage.
• Document supported grpc-swift version(s), Swift toolchain version(s), and compatibility constraints.
• Add a clear end-to-end quickstart: IDL -> codegen -> build -> run server -> run client.
• Document generated files and API shape (service.swift, service_grpc.swift) with method mapping by RPC mode.
• Document codec behavior, error mapping, and zero-copy vs fallback rules and safety constraints.
• Add troubleshooting guidance for common setup/runtime errors and how to diagnose them.
• Provide a minimal performance guide: allocation/copy considerations and recommended usage patterns.

Acceptance Criteria

1. Swift service gRPC code generation produces usable service.swift and service_grpc.swift.
2. Generated code supports unary, client-streaming, server-streaming, and bidi-streaming APIs.
3. Fory-backed grpc-swift codec passes round-trip and error-path tests.
4. Zero-copy decode path exists with tested fallback behavior.
5. Swift gRPC examples run successfully.
6. Comprehensive documentation is added, including quickstart, API/generated-code guide, compatibility/version notes, codec/error behavior, and troubleshooting.

Skills Required

• Swift
• grpc-swift
• Compiler and code generation
• Serialization internals
• Async and streaming APIs
• Testing and performance profiling
• Technical documentation

Difficulty

Medium

Project Size

Preferred: 175hours

Potential Mentors

• Chaokun Yang
• Weipeng Wang

Source Links

• [Compiler][gRPC][Rust] Generate gRPC stubs with tonic + Fory codec #3275
• https://github.com/apache/fory/tree/main/compiler
• https://github.com/apache/fory/tree/main/compiler/fory_compiler
• https://github.com/apache/fory/tree/main/swift
• https://github.com/grpc/grpc-swift

[chaokunyang]

This issue is reserved for gsoc

[chaokunyang]

Please follow https://community.apache.org/gsoc/ for this issue