OpenTelemetry Middleware

A Go library providing OpenTelemetry tracing middleware for gRPC and HTTP services.

Features

• gRPC Server Middleware: Automatic tracing for incoming gRPC requests (unary and streaming)
• gRPC Client Middleware: Automatic tracing for outgoing gRPC requests (unary and streaming)
• HTTP Server Middleware: Automatic tracing for HTTP requests
• HTTP Client Instrumentation: Helper for injecting trace context into outbound HTTP requests
• Configurable OTLP Exporters: Support for both HTTP and gRPC OTLP exporters
• Flexible Sampling: Configurable trace sampling rates

Installation

go get github.com/openprovider/otel-middleware

Usage

Configuration

import "github.com/openprovider/otel-middleware"

config := &otel.Config{
    Enabled:        true,
    Endpoint:       "https://api.honeycomb.io",
    ServiceName:    "my-service",
    ServiceVersion: "1.0.0",
    Environment:    "production",
    Protocol:       "http/protobuf",
    Headers:        "Authorization=Bearer your-api-key",
    BatchTimeout:   5,
    SamplingRate:   1.0,
}

Initialize Provider

ctx := context.Background()
provider, err := otel.New(ctx, config)
if err != nil {
    log.Fatal(err)
}
defer provider.Shutdown(ctx)

gRPC Server Middleware

server := grpc.NewServer(
    grpc.UnaryInterceptor(otel.GRPCUnaryServerInterceptor()),
    grpc.StreamInterceptor(otel.GRPCStreamServerInterceptor()),
)

gRPC Client Middleware

conn, err := grpc.Dial("localhost:9090",
    grpc.WithUnaryInterceptor(otel.GRPCUnaryClientInterceptor()),
    grpc.WithStreamInterceptor(otel.GRPCStreamClientInterceptor()),
)

HTTP Server Middleware

mux := http.NewServeMux()
mux.HandleFunc("/health", healthHandler)

server := &http.Server{
    Handler: otel.HTTPMiddleware(mux),
}

HTTP Client Instrumentation

req, _ := http.NewRequest("GET", "https://api.example.com", nil)
otel.InjectHTTPHeaders(req)
resp, err := http.DefaultClient.Do(req)

Configuration Options

• Enabled: Enable/disable tracing
• Endpoint: OTLP collector endpoint
• ServiceName: Service name for traces
• ServiceVersion: Service version
• Environment: Deployment environment
• Protocol: http, http/protobuf, grpc, or grpc/protobuf
• Headers: Authorization headers (format: Authorization=Bearer token)
• BatchTimeout: Batch export timeout in seconds
• SamplingRate: Trace sampling rate (0.0 to 1.0)

License

Copyright © 2024 Openprovider