grpc-python

# gRPC Python Patterns

High-performance RPC framework for microservice communication.

## Overview

- Internal microservice communication (lower latency than REST)
- Streaming data (real-time updates, file transfers)
- Polyglot environments (shared proto definitions)
- Strong typing between services (compile-time validation)
- Bidirectional streaming (chat, gaming, real-time sync)

## When NOT to Use

- Public APIs (prefer REST/GraphQL for browser compatibility)
- Simple CRUD with few services (REST is simpler)
- When HTTP/2 is not available

## Proto Definition

```protobuf
// protos/user_service.proto
syntax = "proto3";
package user.v1;

import "google/protobuf/timestamp.proto";
import "google/protobuf/empty.proto";

service UserService {
  rpc GetUser(GetUserRequest) returns (User);
  rpc CreateUser(CreateUserRequest) returns (User);
  rpc ListUsers(ListUsersRequest) returns (stream User);  // Server streaming
  rpc BulkCreateUsers(stream CreateUserRequest) returns (BulkCreateResponse);  // Client streaming
  rpc UserUpdates(stream UserUpdateRequest) returns (stream User);  // Bidirectional
}

message User {
  string id = 1;
  string email = 2;
  string name = 3;
  UserStatus status = 4;
  google.protobuf.Timestamp created_at = 5;
}

enum UserStatus {
  USER_STATUS_UNSPECIFIED = 0;
  USER_STATUS_ACTIVE = 1;
  USER_STATUS_INACTIVE = 2;
}

message GetUserRequest { string user_id = 1; }
message CreateUserRequest { string email = 1; string name = 2; string password = 3; }
message ListUsersRequest { int32 page_size = 1; string page_token = 2; }
message BulkCreateResponse { int32 created_count = 1; repeated string user_ids = 2; }
```

### Code Generation

```bash
pip install grpcio grpcio-tools
python -m grpc_tools.protoc -I./protos --python_out=./app/protos --pyi_out=./app/protos --grpc_python_out=./app/protos ./protos/user_service.proto
```

## Server Implementation

```python
import grpc
from concurrent import futures
from google.protobuf.timestamp_pb2 import Times