Background

Apicurio Registry currently uses the com.squareup.wire:wire-schema library (version 5.3.3) for Protocol Buffers schema parsing and manipulation. This library is primarily used in:

• utils/protobuf-schema-utilities module
• schema-util/protobuf module
• serdes/generic/serde-common-protobuf module
• Various protobuf-related components for validation, canonicalization, compatibility checking, and reference handling

Proposal

Investigate replacing the wire-schema library with Quarkus gRPC Zero, a new experimental feature that provides a pure JVM-based approach to Protocol Buffers compilation.

About gRPC Zero

gRPC Zero is an innovative Quarkus extension that:

• Runs protoc compilation entirely within the JVM using WebAssembly
• Eliminates the need for platform-specific native protoc binaries
• Uses Chicory to translate the protobuf engine to pure Java bytecode
• Provides portable, consistent builds across different environments (laptops, CI, containers, edge devices)
• Simplifies continuous integration and reduces maintenance overhead

More information: https://quarkus.io/blog/grpc-zero/

Goals

This proof of concept should explore:

1. Feasibility: Can grpc-zero replace the functionality currently provided by wire-schema?
2. API Compatibility: What changes would be required to adapt existing code?
3. Performance: How does grpc-zero compare in terms of performance?
4. Build Integration: How would grpc-zero integrate with our current Maven build process?
5. Dependencies: What dependency changes would be required? Can we reduce the dependency footprint?

Scope

This is a proof of concept task. The goal is to:

• Create a prototype implementation in a branch
• Document findings about compatibility and migration effort
• Identify any gaps or limitations
• Provide recommendations on whether a full migration would be beneficial

Current wire-schema Usage

Key areas where wire-schema is currently used:

• FileDescriptorUtils - Converting between wire-schema and protobuf descriptors
• ProtobufSchemaLoader - Loading and parsing protobuf schemas
• ProtobufFile - Representing protobuf schema files
• ProtobufContentValidator - Validating protobuf content
• ProtobufCompatibilityChecker - Checking protobuf schema compatibility
• ProtobufReferenceFinder - Finding references in protobuf schemas
• ProtobufDereferencer - Dereferencing protobuf schemas
• ProtobufContentCanonicalizer - Canonicalizing protobuf content

Dependencies to Consider

Current protobuf-related dependencies:

• com.squareup.wire:wire-schema:5.3.3
• com.squareup.wire:wire-schema-jvm:5.3.3
• com.squareup.okio:okio-jvm:3.10.2
• com.squareup.okio:okio-fakefilesystem:3.10.2
• com.ibm.icu:icu4j:76.1
• com.google.protobuf:protobuf-java:4.33.0
• org.xolstice.maven.plugins:protobuf-maven-plugin:0.6.1

Success Criteria

The POC will be considered successful if it demonstrates:

1. Basic protobuf schema parsing and manipulation using grpc-zero
2. A clear migration path for existing wire-schema usage
3. Potential benefits in terms of build portability and simplification
4. No significant performance regressions
5. Reduction in platform-specific build dependencies

References

• gRPC Zero blog post: https://quarkus.io/blog/grpc-zero/
• Chicory WebAssembly runtime: https://chicory.dev
• Current wire-schema dependency: https://github.com/square/wire