tracing: send traces to the otel collector when enabled

commands/bake.go

@@ -45,7 +45,7 @@ type bakeOptions struct {
 func runBake(dockerCli command.Cli, targets []string, in bakeOptions, cFlags commonFlags) (err error) {
 	ctx := appcontext.Context()
 
-	ctx, end, err := tracing.TraceCurrentCommand(ctx, "bake")
+	ctx, end, err := tracing.TraceCurrentCommand(ctx, dockerCli, "bake")
 	if err != nil {
 		return err
 	}

util/tracing/trace.go

@@ -2,16 +2,27 @@ package tracing
 
 import (
 	"context"
+	"fmt"
 	"os"
 	"strings"
 
+	"github.com/docker/cli/cli/command"
 	"github.com/moby/buildkit/util/tracing/detect"
 	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
+	sdktrace "go.opentelemetry.io/otel/sdk/trace"
 	"go.opentelemetry.io/otel/trace"
 )
 
-func TraceCurrentCommand(ctx context.Context, name string) (context.Context, func(error), error) {
-	tp, err := detect.TracerProvider()
+const otelConfigFieldName = "otel"
+
+func TraceCurrentCommand(ctx context.Context, cli command.Cli, name string) (context.Context, func(error), error) {
+	opts, err := tracerProviderOptions(cli)
+	if err != nil {
+		return context.Background(), nil, err
+	}
+
+	tp, err := detect.NewTracerProvider(ctx, opts...)
 	if err != nil {
 		return context.Background(), nil, err
 	}
@@ -25,6 +36,54 @@ func TraceCurrentCommand(ctx context.Context, name string) (context.Context, fun
 		}
 		span.End()
 
-		detect.Shutdown(context.TODO())
+		tp.Shutdown(context.TODO())
+	}, nil
+}
+
+func tracerProviderOptions(cli command.Cli) ([]sdktrace.TracerProviderOption, error) {
+	meta, err := cli.ContextStore().GetMetadata(cli.CurrentContext())
+	if err != nil {
+		return nil, err
+	}
+
+	var otelCfg interface{}
+	switch m := meta.Metadata.(type) {
+	case command.DockerContext:
+		otelCfg = m.AdditionalFields[otelConfigFieldName]
+	case map[string]interface{}:
+		otelCfg = m[otelConfigFieldName]
+	}
+
+	if otelCfg == nil {
+		return nil, nil
+	}
+
+	otelMap, ok := otelCfg.(map[string]interface{})
+	if !ok {
+		return nil, fmt.Errorf(
+			"unexpected type for field %q: %T (expected: %T)",
+			otelConfigFieldName,
+			otelCfg,
+			otelMap,
+		)
+	}
+
+	// keys from https://opentelemetry.io/docs/concepts/sdk-configuration/otlp-exporter-configuration/
+	endpoint, _ := otelMap["OTEL_EXPORTER_OTLP_ENDPOINT"].(string)
+	if endpoint == "" {
+		return nil, nil
+	}
+
+	// Hardcoded endpoint from the endpoint.
+	exp, err := otlptracegrpc.New(context.Background(),
+		otlptracegrpc.WithEndpoint(endpoint),
+		otlptracegrpc.WithInsecure())
+	if err != nil {
+		return nil, err
+	}
+
+	sp := sdktrace.NewBatchSpanProcessor(exp)
+	return []sdktrace.TracerProviderOption{
+		sdktrace.WithSpanProcessor(sp),
 	}, nil
 }