reorganize exporters and simplify their use

example/main.go

@@ -10,8 +10,7 @@ import (
 
 	"git.ma-al.com/gora_filip/observer/pkg/tracer"
 	"git.ma-al.com/gora_filip/pkg/attr"
-	"git.ma-al.com/gora_filip/pkg/combined_exporter"
-	"git.ma-al.com/gora_filip/pkg/console_exporter"
+	"git.ma-al.com/gora_filip/pkg/exporters"
 	"git.ma-al.com/gora_filip/pkg/fiber_tracing"
 	"git.ma-al.com/gora_filip/pkg/level"
 	"github.com/gofiber/fiber/v2"
@@ -26,19 +25,17 @@ func main() {
 		StreamRequestBody: true,
 	})
 
-	lvl := level.DEBUG
-	exporter := combined_exporter.NewExporter(
-		console_exporter.NewExporter(
-			console_exporter.ExporterOptions{
-				FilterOnLevel: &lvl,
-				//EmitOnlyOnError: true,
-			},
-		))
+	exps := make([]exporters.ExporterWithConfig, 2)
+	exps = append(exps, exporters.DevConsoleExporter())
+	gelfExp, err := exporters.GelfExporter()
+	if err == nil {
+		exps = append(exps, gelfExp)
+	}
 	main.Use(fiber_tracing.NewMiddleware(fiber_tracing.Config{
 		AppName:         "example",
 		Version:         "0.0.0",
 		ServiceProvider: "maal",
-		Exporter:        exporter,
+		Exporters:       exps,
 	}))
 	defer fiber_tracing.ShutdownTracer()
 

pkg/combined_exporter/combined_exporter.go

@@ -1,40 +0,0 @@
-package combined_exporter
-
-import (
-	"context"
-	"fmt"
-	"go.opentelemetry.io/otel/sdk/trace"
-)
-
-type Exporter struct {
-	exporters []trace.SpanExporter
-}
-
-func NewExporter(exporters ...trace.SpanExporter) trace.SpanExporter {
-	return &Exporter{
-		exporters: exporters,
-	}
-}
-
-// Implements [trace.SpanExporter]
-func (e *Exporter) ExportSpans(ctx context.Context, spans []trace.ReadOnlySpan) error {
-	for _, exp := range e.exporters {
-		exp.ExportSpans(ctx, spans)
-	}
-	return nil
-}
-
-// Implements [trace.SpanExporter]
-func (e *Exporter) Shutdown(ctx context.Context) error {
-	var errs []error
-	for _, exp := range e.exporters {
-		err := exp.Shutdown(ctx)
-		if err != nil {
-			errs = append(errs, err)
-		}
-	}
-	if len(errs) > 0 {
-		return fmt.Errorf("multiple erros have occured: %#v", errs)
-	}
-	return nil
-}

pkg/exporters/console_exporter/console_exporter.go

@@ -46,6 +46,21 @@ type Exporter struct {
 	stopped        bool
 }
 
+// NOTE: The configuration might change in future releases
+func DefaultConsoleExporter() trace.SpanExporter {
+	lvl := level.DEBUG
+	fmt := NewEventsOnlyFormatter()
+	return NewExporter(ExporterOptions{
+		FilterFromEnvVar: nil,
+		FilterOnLevel:    &lvl,
+		FilterOutFields:  []attribute.Key{},
+		EmitEventsOnly:   false,
+		EmitTraceId:      true,
+		EmitOnlyOnError:  false,
+		TraceFormatter:   &fmt,
+	})
+}
+
 func NewExporter(opts ExporterOptions) trace.SpanExporter {
 	var formatter TraceFormatter
 	var lvl level.SeverityLevel

pkg/exporters/console_exporter/event_only_formatter.go

@@ -14,6 +14,10 @@ import (
 	"go.opentelemetry.io/otel/semconv/v1.25.0"
 )
 
+func NewEventsOnlyFormatter() TraceFormatter {
+	return &EventsOnlyFormatter{}
+}
+
 // A formatter that will print only events using a multiline format with colors.
 // It uses attributes from the [attr] and [semconv] packages.
 type EventsOnlyFormatter struct{}

pkg/exporters/exporters.go

@@ -0,0 +1,58 @@
+package exporters
+
+import (
+	"context"
+	"time"
+
+	"git.ma-al.com/gora_filip/pkg/exporters/console_exporter"
+	gelf_exporter "git.ma-al.com/gora_filip/pkg/exporters/gelf_exporter"
+	otlphttp_exporter "go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
+	sdktrace "go.opentelemetry.io/otel/sdk/trace"
+)
+
+func NewWithConfig(exporter sdktrace.SpanExporter) ExporterWithConfig {
+	return ExporterWithConfig{
+		exporter: exporter,
+	}
+}
+
+// Combined exporter with batch processor config
+type ExporterWithConfig struct {
+	exporter sdktrace.SpanExporter
+	config   []sdktrace.BatchSpanProcessorOption
+}
+
+func (ecfg ExporterWithConfig) Add(opt sdktrace.BatchSpanProcessorOption) ExporterWithConfig {
+	ecfg.config = append(ecfg.config, opt)
+	return ecfg
+}
+
+func (ecfg ExporterWithConfig) IntoTraceProviderOption() sdktrace.TracerProviderOption {
+	return sdktrace.WithBatcher(ecfg.exporter, ecfg.config...)
+}
+
+// An exporter printing to console with very small delay
+func DevConsoleExporter(opts ...console_exporter.ExporterOptions) ExporterWithConfig {
+	batchTimeout := (time.Millisecond * 250)
+	exportTimeout := (time.Millisecond * 250)
+	var exporter ExporterWithConfig
+	if len(opts) > 0 {
+		exporter = NewWithConfig(console_exporter.NewExporter(opts[0]))
+	} else {
+		exporter = NewWithConfig(console_exporter.DefaultConsoleExporter())
+	}
+	return exporter.Add(sdktrace.WithBatchTimeout(batchTimeout)).Add(sdktrace.WithExportTimeout(exportTimeout))
+}
+
+// Default exporter to Graylog.
+func GelfExporter(opts ...gelf_exporter.Option) (ExporterWithConfig, error) {
+	gelfExp, err := gelf_exporter.New(opts...)
+	return NewWithConfig(gelfExp), err
+}
+
+// Exporter for traces over HTTP. Can be used with Jaeger.
+// See documentation of [otlhttp_exporter] for details.
+func OtlpHTTPExporter(opts ...otlphttp_exporter.Option) (ExporterWithConfig, error) {
+	otlpExp, err := otlphttp_exporter.New(context.Background(), opts...)
+	return NewWithConfig(otlpExp), err
+}

pkg/fiber_tracing/fiber_tracing.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"log"
 
+	"git.ma-al.com/gora_filip/pkg/exporters"
 	"github.com/gofiber/fiber/v2"
 	fiberOpentelemetry "github.com/psmarcin/fiber-opentelemetry/pkg/fiber-otel"
 	"go.opentelemetry.io/otel"
@@ -22,8 +23,9 @@ var (
 type Config struct {
 	AppName string
 	Version string
+	// Name of an organization providing the service
 	ServiceProvider string
-	Exporter        trc.SpanExporter
+	Exporters       []exporters.ExporterWithConfig
 }
 
 func newResource(config Config) *resource.Resource {
@@ -39,7 +41,9 @@ func newResource(config Config) *resource.Resource {
 func NewMiddleware(config Config) func(*fiber.Ctx) error {
 	var tracerProviders []trc.TracerProviderOption
 
-	tracerProviders = append(tracerProviders, trc.WithBatcher(config.Exporter))
+	for _, exp := range config.Exporters {
+		tracerProviders = append(tracerProviders, exp.IntoTraceProviderOption())
+	}
 	tracerProviders = append(tracerProviders, trc.WithResource(newResource(config)))
 
 	TP = *trc.NewTracerProvider(tracerProviders...)