first commit

plugins/otel/grpc.go

@@ -0,0 +1,79 @@
+package otel
+
+import (
+	"context"
+	"crypto/tls"
+	"crypto/x509"
+	"fmt"
+	"os"
+
+	collectorpb "go.opentelemetry.io/proto/otlp/collector/trace/v1"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/credentials/insecure"
+	"google.golang.org/grpc/metadata"
+)
+
+// OtelClientGRPC is the implementation of the OpenTelemetry client for gRPC
+type OtelClientGRPC struct {
+	client  collectorpb.TraceServiceClient
+	conn    *grpc.ClientConn
+	headers map[string]string
+}
+
+// NewOtelClientGRPC creates a new OpenTelemetry client for gRPC
+func NewOtelClientGRPC(endpoint string, headers map[string]string, tlsCACert string, insecureMode bool) (*OtelClientGRPC, error) {
+	var creds credentials.TransportCredentials
+	// TLS priority: custom CA > system roots > insecure
+	if tlsCACert != "" {
+		// Validate the CA cert path to prevent path traversal attacks
+		if err := validateCACertPath(tlsCACert); err != nil {
+			return nil, err
+		}
+		// Use custom CA certificate with MinVersion
+		caCert, err := os.ReadFile(tlsCACert)
+		if err != nil {
+			return nil, fmt.Errorf("fail to load provided CA cert: %w", err)
+		}
+		caCertPool := x509.NewCertPool()
+		if !caCertPool.AppendCertsFromPEM(caCert) {
+			return nil, fmt.Errorf("fail to parse provided CA cert")
+		}
+		tlsConfig := &tls.Config{
+			RootCAs:    caCertPool,
+			MinVersion: tls.VersionTLS12,
+		}
+		creds = credentials.NewTLS(tlsConfig)
+	} else if insecureMode {
+		// Skip TLS entirely
+		creds = insecure.NewCredentials()
+	} else {
+		// Use system root CAs with MinVersion
+		tlsConfig := &tls.Config{
+			MinVersion: tls.VersionTLS12,
+		}
+		creds = credentials.NewTLS(tlsConfig)
+	}
+	conn, err := grpc.NewClient(endpoint, grpc.WithTransportCredentials(creds))
+	if err != nil {
+		return nil, err
+	}
+	return &OtelClientGRPC{client: collectorpb.NewTraceServiceClient(conn), conn: conn, headers: headers}, nil
+}
+
+// Emit sends a trace to the OpenTelemetry collector
+func (c *OtelClientGRPC) Emit(ctx context.Context, rs []*ResourceSpan) error {
+	if c.headers != nil {
+		ctx = metadata.NewOutgoingContext(ctx, metadata.New(c.headers))
+	}
+	_, err := c.client.Export(ctx, &collectorpb.ExportTraceServiceRequest{ResourceSpans: rs})
+	return err
+}
+
+// Close closes the gRPC connection
+func (c *OtelClientGRPC) Close() error {
+	if c.conn != nil {
+		return c.conn.Close()
+	}
+	return nil
+}