Trace#

_, span := tracer.Start(reg.Request.Context(), "getUser", oteltrace.WithAttributes(attribute.String("id", uid)))
defer span.End()

package main

import (
    "context"
    "log"
    "net/http"
    "time"

    "go.opentelemetry.io/otel"
    "go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
    "go.opentelemetry.io/otel/propagation"
    "go.opentelemetry.io/otel/sdk/resource"
    sdktrace "go.opentelemetry.io/otel/sdk/trace"
    semconv "go.opentelemetry.io/otel/semconv/v1.21.0"
    "google.golang.org/grpc"
    "google.golang.org/grpc/credentials/insecure"
)

func main() {
    ctx := context.Background()

    // 1. 初始化导出器 (连接到本地Collector)
    traceExporter, err := otlptracegrpc.New(ctx,
        otlptracegrpc.WithEndpoint("localhost:4317"), // OTLP gRPC 收集器端点
        otlptracegrpc.WithInsecure(),                 // 开发环境使用非安全连接
        // otlptracegrpc.WithDialOption(grpc.WithBlock()), // 可选：阻塞连接
    )
    if err != nil {
        log.Fatalf("failed to create trace exporter: %v", err)
    }

    // 2. 配置资源
    res, err := resource.New(ctx,
        resource.WithAttributes(
            semconv.ServiceNameKey.String("my-awesome-go-service"),
            semconv.ServiceVersionKey.String("1.0.0"),
        ),
        resource.WithProcess(),
        resource.WithHost(),
    )
    if err != nil {
        log.Fatalf("failed to create resource: %v", err)
    }

    // 3. 创建 BatchSpanProcessor 和 TracerProvider
    bsp := sdktrace.NewBatchSpanProcessor(traceExporter)
    tp := sdktrace.NewTracerProvider(
        sdktrace.WithSampler(sdktrace.AlwaysSample()),
        sdktrace.WithResource(res),
        sdktrace.WithSpanProcessor(bsp),
    )
    defer func() {
        // 7. 优雅关闭
        ctx, cancel := context.WithTimeout(ctx, 5*time.Second)
        defer cancel()
        if err := tp.Shutdown(ctx); err != nil {
            log.Fatalf("failed to shutdown TracerProvider: %v", err)
        }
    }()

    // 4. 设置全局 TracerProvider 和 Propagator
    otel.SetTracerProvider(tp)
    otel.SetTextMapPropagator(propagation.TraceContext{})

    // 5. 使用自动 Instrumentation 包装 HTTP 处理器
    http.HandleFunc("/hello", func(w http.ResponseWriter, r *http.Request) {
        // 手动创建一个Span来记录一些操作
        tracer := otel.Tracer("example-tracer")
        ctx, span := tracer.Start(r.Context(), "my-handler-logic")
        defer span.End()

        // 模拟一些工作
        time.Sleep(100 * time.Millisecond)
        span.AddEvent("Did some work!")

        w.Write([]byte("Hello, World!"))
    })

    // 使用 otelhttp 中间件包装整个路由（可选，但推荐用于自动处理HTTP请求的Span）
    wrappedHandler := otelhttp.NewHandler(http.DefaultServeMux, "server")

    log.Println("Starting server on :8080")
    if err := http.ListenAndServe(":8080", wrappedHandler); err != nil {
        log.Fatalf("failed to start server: %v", err)
    }
}