#gRPC / Protobuf

#Overview

Cheolsu Proxy automatically detects gRPC traffic and decodes Protobuf messages into human-readable format. Messages are auto-decoded using Wire Type analysis without requiring .proto definition files.

#Auto-Detection

gRPC traffic is automatically detected by:

• Content-Type starting with application/grpc or application/grpc+proto
• Content-Type subtype extraction (e.g., proto, json)

#Analysis Information

#Metadata

#gRPC Status Codes

#Protobuf Frame Parsing

gRPC bodies use the Length-Prefixed Message format:

[Compressed-Flag (1 byte)] [Message-Length (4 bytes, Big Endian)] [Message]

Each frame's compression status and message data are parsed separately. Wire Type-based field auto-decoding allows inspecting message structure without .proto files.

#Use Cases

#Microservice Debugging

Monitor inter-service gRPC communication and filter requests by service/method to trace specific RPC calls.

#Error Diagnosis

Check gRPC status codes and messages to identify request failure causes. Track statuses like DEADLINE_EXCEEDED and UNAVAILABLE to diagnose network issues or service outages.

#Payload Inspection

Examine Protobuf message field structures to verify that request/response data is serialized as expected.

#Usage

#Desktop

Select a gRPC request in the traffic log to view service/method info, status codes, and decoded Protobuf messages in the transaction detail view.

#MCP

"Show me gRPC traffic"
"Find gRPC requests with DEADLINE_EXCEEDED status"