Elia Battiston | ac8d23f | 2022-03-14 17:54:56 +0100 | [diff] [blame^] | 1 | // Copyright 2017 Michal Witkowski. All Rights Reserved. |
| 2 | // See LICENSE for licensing terms. |
| 3 | |
| 4 | package grpc_opentracing |
| 5 | |
| 6 | import ( |
| 7 | "context" |
| 8 | |
| 9 | "github.com/grpc-ecosystem/go-grpc-middleware" |
| 10 | "github.com/grpc-ecosystem/go-grpc-middleware/tags" |
| 11 | "github.com/grpc-ecosystem/go-grpc-middleware/util/metautils" |
| 12 | "github.com/opentracing/opentracing-go" |
| 13 | "github.com/opentracing/opentracing-go/ext" |
| 14 | "github.com/opentracing/opentracing-go/log" |
| 15 | "google.golang.org/grpc" |
| 16 | "google.golang.org/grpc/grpclog" |
| 17 | ) |
| 18 | |
| 19 | var ( |
| 20 | grpcTag = opentracing.Tag{Key: string(ext.Component), Value: "gRPC"} |
| 21 | ) |
| 22 | |
| 23 | // UnaryServerInterceptor returns a new unary server interceptor for OpenTracing. |
| 24 | func UnaryServerInterceptor(opts ...Option) grpc.UnaryServerInterceptor { |
| 25 | o := evaluateOptions(opts) |
| 26 | return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) { |
| 27 | if o.filterOutFunc != nil && !o.filterOutFunc(ctx, info.FullMethod) { |
| 28 | return handler(ctx, req) |
| 29 | } |
| 30 | opName := info.FullMethod |
| 31 | if o.opNameFunc != nil { |
| 32 | opName = o.opNameFunc(info.FullMethod) |
| 33 | } |
| 34 | newCtx, serverSpan := newServerSpanFromInbound(ctx, o.tracer, o.traceHeaderName, opName) |
| 35 | if o.unaryRequestHandlerFunc != nil { |
| 36 | o.unaryRequestHandlerFunc(serverSpan, req) |
| 37 | } |
| 38 | resp, err := handler(newCtx, req) |
| 39 | finishServerSpan(ctx, serverSpan, err) |
| 40 | return resp, err |
| 41 | } |
| 42 | } |
| 43 | |
| 44 | // StreamServerInterceptor returns a new streaming server interceptor for OpenTracing. |
| 45 | func StreamServerInterceptor(opts ...Option) grpc.StreamServerInterceptor { |
| 46 | o := evaluateOptions(opts) |
| 47 | return func(srv interface{}, stream grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error { |
| 48 | if o.filterOutFunc != nil && !o.filterOutFunc(stream.Context(), info.FullMethod) { |
| 49 | return handler(srv, stream) |
| 50 | } |
| 51 | opName := info.FullMethod |
| 52 | if o.opNameFunc != nil { |
| 53 | opName = o.opNameFunc(info.FullMethod) |
| 54 | } |
| 55 | newCtx, serverSpan := newServerSpanFromInbound(stream.Context(), o.tracer, o.traceHeaderName, opName) |
| 56 | wrappedStream := grpc_middleware.WrapServerStream(stream) |
| 57 | wrappedStream.WrappedContext = newCtx |
| 58 | err := handler(srv, wrappedStream) |
| 59 | finishServerSpan(newCtx, serverSpan, err) |
| 60 | return err |
| 61 | } |
| 62 | } |
| 63 | |
| 64 | func newServerSpanFromInbound(ctx context.Context, tracer opentracing.Tracer, traceHeaderName, opName string) (context.Context, opentracing.Span) { |
| 65 | md := metautils.ExtractIncoming(ctx) |
| 66 | parentSpanContext, err := tracer.Extract(opentracing.HTTPHeaders, metadataTextMap(md)) |
| 67 | if err != nil && err != opentracing.ErrSpanContextNotFound { |
| 68 | grpclog.Infof("grpc_opentracing: failed parsing trace information: %v", err) |
| 69 | } |
| 70 | |
| 71 | serverSpan := tracer.StartSpan( |
| 72 | opName, |
| 73 | // this is magical, it attaches the new span to the parent parentSpanContext, and creates an unparented one if empty. |
| 74 | ext.RPCServerOption(parentSpanContext), |
| 75 | grpcTag, |
| 76 | ) |
| 77 | |
| 78 | injectOpentracingIdsToTags(traceHeaderName, serverSpan, grpc_ctxtags.Extract(ctx)) |
| 79 | return opentracing.ContextWithSpan(ctx, serverSpan), serverSpan |
| 80 | } |
| 81 | |
| 82 | func finishServerSpan(ctx context.Context, serverSpan opentracing.Span, err error) { |
| 83 | // Log context information |
| 84 | tags := grpc_ctxtags.Extract(ctx) |
| 85 | for k, v := range tags.Values() { |
| 86 | // Don't tag errors, log them instead. |
| 87 | if vErr, ok := v.(error); ok { |
| 88 | serverSpan.LogKV(k, vErr.Error()) |
| 89 | } else { |
| 90 | serverSpan.SetTag(k, v) |
| 91 | } |
| 92 | } |
| 93 | if err != nil { |
| 94 | ext.Error.Set(serverSpan, true) |
| 95 | serverSpan.LogFields(log.String("event", "error"), log.String("message", err.Error())) |
| 96 | } |
| 97 | serverSpan.Finish() |
| 98 | } |