feat: opentelemetry integration, removed self designed tracing (#1111)

* feat: opentelemetry integration, removed self designed tracing

* feat: support zipkin on opentelemetry integration

* feat: support zipkin on opentelemetry integration, enable it in conf

* style: format code

* fix: support logx without exporter configured

* fix: check return values

* refactor: simplify code

* refactor: simplify opentelemetry integration

* ci: fix staticcheck errors

core/trace/agent.go

@@ -0,0 +1,69 @@
+package trace
+
+import (
+	"fmt"
+	"sync"
+
+	"github.com/tal-tech/go-zero/core/logx"
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/exporters/jaeger"
+	"go.opentelemetry.io/otel/exporters/zipkin"
+	"go.opentelemetry.io/otel/propagation"
+	"go.opentelemetry.io/otel/sdk/resource"
+	sdktrace "go.opentelemetry.io/otel/sdk/trace"
+	semconv "go.opentelemetry.io/otel/semconv/v1.4.0"
+)
+
+const (
+	kindJaeger = "jaeger"
+	kindZipkin = "zipkin"
+)
+
+var once sync.Once
+
+// StartAgent starts a opentelemetry agent.
+func StartAgent(c Config) {
+	once.Do(func() {
+		startAgent(c)
+	})
+}
+
+func createExporter(c Config) (sdktrace.SpanExporter, error) {
+	// Just support jaeger now, more for later
+	switch c.Batcher {
+	case kindJaeger:
+		return jaeger.New(jaeger.WithCollectorEndpoint(jaeger.WithEndpoint(c.Endpoint)))
+	case kindZipkin:
+		return zipkin.New(c.Endpoint)
+	default:
+		return nil, fmt.Errorf("unknown exporter: %s", c.Batcher)
+	}
+}
+
+func startAgent(c Config) {
+	opts := []sdktrace.TracerProviderOption{
+		// Set the sampling rate based on the parent span to 100%
+		sdktrace.WithSampler(sdktrace.ParentBased(sdktrace.TraceIDRatioBased(c.Sampler))),
+		// Record information about this application in an Resource.
+		sdktrace.WithResource(resource.NewSchemaless(semconv.ServiceNameKey.String(c.Name))),
+	}
+
+	if len(c.Endpoint) > 0 {
+		exp, err := createExporter(c)
+		if err != nil {
+			logx.Error(err)
+			return
+		}
+
+		// Always be sure to batch in production.
+		opts = append(opts, sdktrace.WithBatcher(exp))
+	}
+
+	tp := sdktrace.NewTracerProvider(opts...)
+	otel.SetTracerProvider(tp)
+	otel.SetTextMapPropagator(propagation.NewCompositeTextMapPropagator(
+		propagation.TraceContext{}, propagation.Baggage{}))
+	otel.SetErrorHandler(otel.ErrorHandlerFunc(func(err error) {
+		logx.Errorf("[otel] error: %v", err)
+	}))
+}