gRPC & Protobuf

⚡ gRPC & Protocol Buffers

Checklist

• Protobuf proto3: scalar types, oneof, repeated, map, well-known types (Timestamp, Duration, FieldMask)
• Wire format basics (varints, field numbers) and why it’s compact
• Schema evolution rules: never reuse field numbers, reserved, adding fields is safe
• buf: lint, breaking-change detection, codegen, BSR ⭐
• gRPC over HTTP/2: unary, server streaming, client streaming, bidi streaming
• Deadlines/timeouts & propagation; cancellation
• Status codes, rich error details
• Interceptors (auth, logging, metrics, tracing)
• Load balancing gotcha: long-lived HTTP/2 connections → need L7 (Envoy) or client-side LB
• gRPC-Gateway / Connect (gRPC + HTTP/JSON from browsers)
• Health checking protocol, reflection, grpcurl
• Protobuf as the Kafka event schema (with a Schema Registry)

🧪 Labs (🟢 warm-up → 🟡 core → 🔴 hard → ⚫ boss)

• 🟢 A proto/ module with buf lint + breaking checks in CI
• 🟡 A Java client ↔ Go server with deadlines + interceptors
• 🔴 Server-streaming run events (engine → api)
• ⚫ The load-balancing gotcha on K8s: reproduce it, then fix it with Envoy or client-side LB

🧠 Cognitive tasks

• Wireshark a gRPC call: find the 5-byte prefix and grpc-status trailers

🛰️ Orbit integration

• orbit-api ↔ engine ↔ worker contracts; Protobuf Kafka events

Go deeper

⚙️ Network Stack Internals · Envoy Internals

Resources

• grpc.io docs · protobuf.dev · buf.build docs · gRPC: Up and Running