TUN-5989: Add in-memory otlp exporter

tracing/client.go

@@ -0,0 +1,90 @@
+package tracing
+
+import (
+	"context"
+	"encoding/base64"
+	"errors"
+	"sync"
+
+	coltracepb "go.opentelemetry.io/proto/otlp/collector/trace/v1"
+	tracepb "go.opentelemetry.io/proto/otlp/trace/v1"
+	"google.golang.org/protobuf/proto"
+)
+
+const (
+	maxTraceAmount = 20
+)
+
+var (
+	errNoTraces = errors.New("no traces recorded to be exported")
+)
+
+type InMemoryClient interface {
+	// Spans returns a copy of the list of in-memory stored spans as a base64
+	// encoded otlp protobuf string.
+	Spans() (string, error)
+}
+
+// InMemoryOtlpClient is a client implementation for otlptrace.Client
+type InMemoryOtlpClient struct {
+	mu    sync.Mutex
+	spans []*tracepb.ResourceSpans
+}
+
+func (mc *InMemoryOtlpClient) Start(_ context.Context) error {
+	return nil
+}
+
+func (mc *InMemoryOtlpClient) Stop(_ context.Context) error {
+	return nil
+}
+
+// UploadTraces adds the provided list of spans to the in-memory list.
+func (mc *InMemoryOtlpClient) UploadTraces(_ context.Context, protoSpans []*tracepb.ResourceSpans) error {
+	mc.mu.Lock()
+	defer mc.mu.Unlock()
+	// Catch to make sure too many traces aren't being added to response header.
+	// Returning nil makes sure we don't fail to send the traces we already recorded.
+	if len(mc.spans)+len(protoSpans) > maxTraceAmount {
+		return nil
+	}
+	mc.spans = append(mc.spans, protoSpans...)
+	return nil
+}
+
+// Spans returns the list of in-memory stored spans as a base64 encoded otlp protobuf string.
+func (mc *InMemoryOtlpClient) Spans() (string, error) {
+	mc.mu.Lock()
+	defer mc.mu.Unlock()
+	if len(mc.spans) <= 0 {
+		return "", errNoTraces
+	}
+	pbRequest := &coltracepb.ExportTraceServiceRequest{
+		ResourceSpans: mc.spans,
+	}
+	data, err := proto.Marshal(pbRequest)
+	if err != nil {
+		return "", err
+	}
+	return base64.StdEncoding.EncodeToString(data), nil
+}
+
+// NoopOtlpClient is a client implementation for otlptrace.Client that does nothing
+type NoopOtlpClient struct{}
+
+func (mc *NoopOtlpClient) Start(_ context.Context) error {
+	return nil
+}
+
+func (mc *NoopOtlpClient) Stop(_ context.Context) error {
+	return nil
+}
+
+func (mc *NoopOtlpClient) UploadTraces(_ context.Context, _ []*tracepb.ResourceSpans) error {
+	return nil
+}
+
+// Spans always returns no traces error
+func (mc *NoopOtlpClient) Spans() (string, error) {
+	return "", errNoTraces
+}