start reworking exporters to be more composable

pkg/tracer/middleware.go

@@ -3,157 +3,13 @@ package tracer
 import (
 	"context"
 	"fmt"
-	"log"
-	"os"
-	"runtime"
-
-	gelfexporter "git.ma-al.com/gora_filip/observer/pkg/gelf_exporter"
 	"github.com/gofiber/fiber/v2"
 	fiberOpentelemetry "github.com/psmarcin/fiber-opentelemetry/pkg/fiber-otel"
-	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
-	"go.opentelemetry.io/otel/codes"
-	"go.opentelemetry.io/otel/exporters/otlp/otlptrace"
-	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
-	"go.opentelemetry.io/otel/exporters/stdout/stdouttrace"
-	"go.opentelemetry.io/otel/sdk/resource"
-	trc "go.opentelemetry.io/otel/sdk/trace"
-	semconv "go.opentelemetry.io/otel/semconv/v1.4.0"
 	trace "go.opentelemetry.io/otel/trace"
+	"runtime"
 )
 
-var (
-	TracingError error = nil
-	TP           trc.TracerProvider
-)
-
-type CustomExporter struct {
-	jaeger      *otlptrace.Exporter
-	stdouttrace *stdouttrace.Exporter
-}
-
-type Config struct {
-	AppName   string
-	JaegerUrl string
-	GelfUrl   string
-	Version   string
-}
-
-func NewCustomExporter(jaegerUrl string) (trc.SpanExporter, error) {
-	var jaeg *otlptrace.Exporter
-	var outrace *stdouttrace.Exporter
-	var err error
-
-	outrace, err = stdouttrace.New(
-		stdouttrace.WithWriter(os.Stdout),
-		stdouttrace.WithPrettyPrint(),
-		stdouttrace.WithoutTimestamps(),
-	)
-	if err != nil {
-		return &CustomExporter{}, err
-	}
-
-	if len(jaegerUrl) > 0 {
-		jaeg = otlptracehttp.NewUnstarted(otlptracehttp.WithEndpointURL(jaegerUrl))
-	}
-
-	return &CustomExporter{
-		jaeger:      jaeg,
-		stdouttrace: outrace,
-	}, nil
-
-}
-
-func (e *CustomExporter) ExportSpans(ctx context.Context, spans []trc.ReadOnlySpan) error {
-	if TracingError == nil {
-		if e.jaeger != nil {
-			err := e.jaeger.ExportSpans(ctx, spans)
-			return err
-		} else {
-			return e.printOnlyOnError(ctx, spans)
-		}
-	}
-	return nil
-}
-
-func (e *CustomExporter) printOnlyOnError(ctx context.Context, spans []trc.ReadOnlySpan) error {
-	var err error
-	for _, s := range spans {
-		if s.Status().Code == codes.Error {
-			err = e.stdouttrace.ExportSpans(ctx, spans)
-			break
-		}
-	}
-	return err
-}
-
-func (e *CustomExporter) Shutdown(ctx context.Context) error {
-	if e.jaeger != nil {
-		e.stdouttrace.Shutdown(ctx)
-		return e.jaeger.Shutdown(ctx)
-	} else {
-		return e.stdouttrace.Shutdown(ctx)
-	}
-}
-
-func newResource(config Config) *resource.Resource {
-	r := resource.NewWithAttributes(
-		semconv.SchemaURL,
-		semconv.ServiceNameKey.String(config.AppName),
-		semconv.ServiceVersionKey.String(config.Version),
-		attribute.String("service.provider", "maal"),
-	)
-	return r
-}
-
-func NewTracer(config Config) func(*fiber.Ctx) error {
-	l := log.New(os.Stdout, "", 0)
-
-	var tracerProviders []trc.TracerProviderOption
-
-	otlpExporter := otlptracehttp.NewUnstarted(otlptracehttp.WithEndpointURL(config.JaegerUrl))
-
-	gelfExporter, err := gelfexporter.New(
-		gelfexporter.WithGelfUrl(config.GelfUrl),
-		gelfexporter.WithAppName("salego"),
-	)
-	if err != nil {
-		l.Fatal(err)
-	}
-	tracerProviders = append(tracerProviders, trc.WithBatcher(otlpExporter))
-	tracerProviders = append(tracerProviders, trc.WithBatcher(gelfExporter))
-	tracerProviders = append(tracerProviders, trc.WithResource(newResource(config)))
-
-	TP = *trc.NewTracerProvider(tracerProviders...)
-
-	otel.SetTracerProvider(&TP)
-	otel.SetErrorHandler(otel.ErrorHandlerFunc(func(err error) {
-		if err != TracingError {
-			TracingError = err
-			log.Println(err)
-		}
-	}))
-
-	tracer := TP.Tracer("fiber-otel-router")
-
-	return fiberOpentelemetry.New(
-		fiberOpentelemetry.Config{
-			Tracer:   tracer,
-			SpanName: "{{ .Method }} {{ .Path }}",
-			TracerStartAttributes: []trace.SpanStartOption{
-				trace.WithSpanKind(trace.SpanKindServer),
-				trace.WithNewRoot(),
-			},
-		},
-	)
-}
-
-func ShutdownTracer() {
-	if err := TP.Shutdown(context.Background()); err != nil {
-		log.Fatal(err)
-	}
-}
-
 func Handler(fc *fiber.Ctx) (context.Context, trace.Span) {
 	spanName := fmt.Sprint(fc.OriginalURL())
 	simpleCtx, span := fiberOpentelemetry.Tracer.Start(fc.UserContext(), spanName)