gRPC Introduction — High-Performance Microservices Communication

# protobuf_intro.py
# Protocol Buffers definition

def protobuf_example():
    print("Protocol Buffers (.proto) Example")
    print("=" * 40)
    print()
    print('syntax = "proto3";')
    print()
    print("package user.v1;")
    print()
    print('service UserService {')
    print("  rpc GetUser (GetUserRequest) returns (User);")
    print("  rpc ListUsers (ListUsersRequest) returns (ListUsersResponse);")
    print("}")
    print()
    print("message GetUserRequest {")
    print("  string user_id = 1;")
    print("}")
    print()
    print("message User {")
    print("  string id = 1;")
    print("  string email = 2;")
    print("  string name = 3;")
    print("  int32 age = 4;")
    print("}")
    print()
    print("Benefits:")
    print("- Strongly typed schema for all messages")
    print("- Backward compatible field evolution")
    print("- Code generation for multiple languages")
    print("- Binary format ~10x smaller than JSON")

protobuf_example()

# http2_benefits.py
# HTTP/2 features used by gRPC

def http2_features():
    print("HTTP/2 Features Used by gRPC")
    print("=" * 40)
    print()
    
    features = [
        {
            "feature": "Multiplexing",
            "desc": "Multiple streams over single TCP connection",
            "benefit": "No head-of-line blocking, fewer connections"
        },
        {
            "feature": "Server Push",
            "desc": "Server sends resources client hasn't requested yet",
            "benefit": "Reduces round trips for related data"
        },
        {
            "feature": "Binary Framing",
            "desc": "All data transmitted in binary frames",
            "benefit": "Efficient parsing, smaller overhead"
        },
        {
            "feature": "Stream Prioritization",
            "desc": "Client can prioritize certain streams",
            "benefit": "Critical requests get bandwidth first"
        },
        {
            "feature": "Header Compression",
            "desc": "HPACK compression for HTTP headers",
            "benefit": "Reduces header overhead significantly"
        },
    ]
    
    for f in features:
        print(f"{f['feature']:25s}")
        print(f"  Description: {f['desc']}")
        print(f"  Benefit:     {f['benefit']}")
        print()

http2_features()

# grpc_vs_rest.py
# Detailed comparison

def compare_grpc_rest():
    print("gRPC vs REST Comparison")
    print("=" * 40)
    print()
    
    comparisons = [
        ("Protocol", "HTTP/2 (binary)", "HTTP/1.1 or HTTP/2 (text)"),
        ("Data Format", "Protocol Buffers (binary)", "JSON or XML (text)"),
        ("Contract", "Required (.proto file)", "Optional (OpenAPI)"),
        ("Streaming", "Bidirectional streaming", "Request-response only"),
        ("Code Generation", "Built-in", "Third-party tools"),
        ("Browser Support", "Limited (needs gRPC-web)", "Native support"),
        ("Payload Size", "~30% of JSON size", "Full text size"),
        ("Parsing Speed", "~10x faster than JSON", "Slower text parsing"),
        ("Human Readability", "No (binary)", "Yes (JSON text)"),
    ]
    
    print(f"{'Aspect':25s} {'gRPC':35s} {'REST':35s}")
    print("-" * 95)
    for aspect, grpc, rest in comparisons:
        print(f"{aspect:25s} {grpc:35s} {rest:35s}")

compare_grpc_rest()

# when_grpc.py
# Decision criteria for gRPC

def when_to_use_grpc():
    print("When to Choose gRPC")
    print("=" * 40)
    print()
    
    criteria = [
        {
            "condition": "High internal traffic between services",
            "reason": "Binary protocol reduces bandwidth and parsing overhead"
        },
        {
            "condition": "Real-time streaming requirements",
            "reason": "gRPC supports bidirectional streaming natively"
        },
        {
            "condition": "Polyglot environment (multiple languages)",
            "reason": "Code generation produces native clients in 11+ languages"
        },
        {
            "condition": "Performance-critical paths",
            "reason": "Protobuf serialization is 10x faster than JSON"
        },
        {
            "condition": "Strong contract enforcement needed",
            "reason": "Breaking changes caught at compile time, not runtime"
        },
    ]
    
    for c in criteria:
        print(f"  Condition: {c['condition']}")
        print(f"  Reason:    {c['reason']}")
        print()

when_to_use_grpc()

def file_processing_proto():
    print("File Processing gRPC Service")
    print("=" * 40)
    print()
    print('syntax = "proto3";')
    print()
    print("package fileproc.v1;")
    print()
    print('service FileProcessor {')
    print("  rpc ProcessFile (ProcessRequest) returns (stream ProgressResponse);")
    print("}")
    print()
    print("message ProcessRequest {")
    print("  string filename = 1;")
    print("  bytes content = 2;")
    print("  string compression_type = 3;")
    print("}")
    print()
    print("message ProgressResponse {")
    print("  int32 percent_complete = 1;")
    print("  string status = 2;")
    print("  string result_url = 3;")
    print("}")
    print()
    print("Usage:")
    print("  Client sends ProcessRequest once")
    print("  Server streams ProgressResponse updates")
    print("  Client shows real-time progress bar")

file_processing_proto()