| // Copyright 2017 Michal Witkowski. All Rights Reserved. |
| // See LICENSE for licensing terms. |
| |
| package grpc_opentracing |
| |
| import ( |
| "github.com/grpc-ecosystem/go-grpc-middleware" |
| "github.com/grpc-ecosystem/go-grpc-middleware/tags" |
| "github.com/grpc-ecosystem/go-grpc-middleware/util/metautils" |
| "github.com/opentracing/opentracing-go" |
| "github.com/opentracing/opentracing-go/ext" |
| "github.com/opentracing/opentracing-go/log" |
| "golang.org/x/net/context" |
| "google.golang.org/grpc" |
| "google.golang.org/grpc/grpclog" |
| ) |
| |
| var ( |
| grpcTag = opentracing.Tag{Key: string(ext.Component), Value: "gRPC"} |
| ) |
| |
| // UnaryServerInterceptor returns a new unary server interceptor for OpenTracing. |
| func UnaryServerInterceptor(opts ...Option) grpc.UnaryServerInterceptor { |
| o := evaluateOptions(opts) |
| return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) { |
| if o.filterOutFunc != nil && !o.filterOutFunc(ctx, info.FullMethod) { |
| return handler(ctx, req) |
| } |
| newCtx, serverSpan := newServerSpanFromInbound(ctx, o.tracer, info.FullMethod) |
| resp, err := handler(newCtx, req) |
| finishServerSpan(ctx, serverSpan, err) |
| return resp, err |
| } |
| } |
| |
| // StreamServerInterceptor returns a new streaming server interceptor for OpenTracing. |
| func StreamServerInterceptor(opts ...Option) grpc.StreamServerInterceptor { |
| o := evaluateOptions(opts) |
| return func(srv interface{}, stream grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error { |
| if o.filterOutFunc != nil && !o.filterOutFunc(stream.Context(), info.FullMethod) { |
| return handler(srv, stream) |
| } |
| newCtx, serverSpan := newServerSpanFromInbound(stream.Context(), o.tracer, info.FullMethod) |
| wrappedStream := grpc_middleware.WrapServerStream(stream) |
| wrappedStream.WrappedContext = newCtx |
| err := handler(srv, wrappedStream) |
| finishServerSpan(newCtx, serverSpan, err) |
| return err |
| } |
| } |
| |
| func newServerSpanFromInbound(ctx context.Context, tracer opentracing.Tracer, fullMethodName string) (context.Context, opentracing.Span) { |
| md := metautils.ExtractIncoming(ctx) |
| parentSpanContext, err := tracer.Extract(opentracing.HTTPHeaders, metadataTextMap(md)) |
| if err != nil && err != opentracing.ErrSpanContextNotFound { |
| grpclog.Printf("grpc_opentracing: failed parsing trace information: %v", err) |
| } |
| |
| serverSpan := tracer.StartSpan( |
| fullMethodName, |
| // this is magical, it attaches the new span to the parent parentSpanContext, and creates an unparented one if empty. |
| ext.RPCServerOption(parentSpanContext), |
| grpcTag, |
| ) |
| |
| injectOpentracingIdsToTags(serverSpan, grpc_ctxtags.Extract(ctx)) |
| return opentracing.ContextWithSpan(ctx, serverSpan), serverSpan |
| } |
| |
| func finishServerSpan(ctx context.Context, serverSpan opentracing.Span, err error) { |
| // Log context information |
| tags := grpc_ctxtags.Extract(ctx) |
| for k, v := range tags.Values() { |
| // Don't tag errors, log them instead. |
| if vErr, ok := v.(error); ok { |
| serverSpan.LogKV(k, vErr.Error()) |
| |
| } else { |
| serverSpan.SetTag(k, v) |
| } |
| } |
| if err != nil { |
| ext.Error.Set(serverSpan, true) |
| serverSpan.LogFields(log.String("event", "error"), log.String("message", err.Error())) |
| } |
| serverSpan.Finish() |
| } |