Support grpc v1.2

contrib/google.golang.org/grpc.v12/compile.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+# compiles test fixtures
+set -e
+protoc -I . fixtures.proto --go_out=plugins=grpc:.
+
+# FIXME[matt] hacks to move the fixtures into the testing package
+# and make it pass our lint rules. This is cheesy but very simple.
+mv fixtures.pb.go fixtures_test.go
+sed -i 's/_Fixture_Ping_Handler/fixturePingHandler/' fixtures_test.go
+sed -i 's/_Fixture_serviceDesc/fixtureServiceDesc/' fixtures_test.go

contrib/google.golang.org/grpc.v12/fixtures.proto

@@ -0,0 +1,22 @@
+syntax = "proto3";
+
+option java_multiple_files = true;
+option java_package = "io.grpc.examples.testgrpc";
+option java_outer_classname = "TestGRPCProto";
+
+package grpc;
+
+service Fixture {
+
+  rpc Ping (FixtureRequest) returns (FixtureReply) {}
+}
+
+// The request message containing the user's name.
+message FixtureRequest {
+  string name = 1;
+}
+
+// The response message containing the greetings
+message FixtureReply {
+  string message = 1;
+}

contrib/google.golang.org/grpc.v12/grpc.go

@@ -0,0 +1,118 @@
+package grpc
+
+import (
+	"fmt"
+	"strconv"
+
+	"github.com/DataDog/dd-trace-go/tracer"
+	"github.com/DataDog/dd-trace-go/tracer/ext"
+
+	context "golang.org/x/net/context"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/metadata"
+)
+
+// pass trace ids with these headers
+const (
+	traceIDKey  = "x-datadog-trace-id"
+	parentIDKey = "x-datadog-parent-id"
+)
+
+// UnaryServerInterceptor will trace requests to the given grpc server.
+func UnaryServerInterceptor(service string, t *tracer.Tracer) grpc.UnaryServerInterceptor {
+	t.SetServiceInfo(service, "grpc-server", ext.AppTypeRPC)
+	return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
+		if !t.Enabled() {
+			return handler(ctx, req)
+		}
+
+		span := serverSpan(t, ctx, info.FullMethod, service)
+		resp, err := handler(tracer.ContextWithSpan(ctx, span), req)
+		span.FinishWithErr(err)
+		return resp, err
+	}
+}
+
+// UnaryClientInterceptor will add tracing to a gprc client.
+func UnaryClientInterceptor(service string, t *tracer.Tracer) grpc.UnaryClientInterceptor {
+	t.SetServiceInfo(service, "grpc-client", ext.AppTypeRPC)
+	return func(ctx context.Context, method string, req, reply interface{}, cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error {
+
+		var child *tracer.Span
+		span, ok := tracer.SpanFromContext(ctx)
+
+		// only trace the request if this is already part of a trace.
+		// does this make sense?
+		if ok && span.Tracer() != nil {
+			t := span.Tracer()
+			child = t.NewChildSpan("grpc.client", span)
+			child.SetMeta("grpc.method", method)
+			ctx = setIDs(child, ctx)
+			ctx = tracer.ContextWithSpan(ctx, child)
+			// FIXME[matt] add the host / port information here
+			// https://github.com/grpc/grpc-go/issues/951
+		}
+
+		err := invoker(ctx, method, req, reply, cc, opts...)
+		if child != nil {
+			child.SetMeta("grpc.code", grpc.Code(err).String())
+			child.FinishWithErr(err)
+
+		}
+		return err
+	}
+}
+
+func serverSpan(t *tracer.Tracer, ctx context.Context, method, service string) *tracer.Span {
+	span := t.NewRootSpan("grpc.server", service, method)
+	span.SetMeta("gprc.method", method)
+	span.Type = "go"
+
+	traceID, parentID := getIDs(ctx)
+	if traceID != 0 && parentID != 0 {
+		span.TraceID = traceID
+		span.ParentID = parentID
+	}
+
+	return span
+}
+
+// setIDs will set the trace ids on the context{
+func setIDs(span *tracer.Span, ctx context.Context) context.Context {
+	if span == nil || span.TraceID == 0 {
+		return ctx
+	}
+
+	md := metadata.New(map[string]string{
+		traceIDKey:  fmt.Sprint(span.TraceID),
+		parentIDKey: fmt.Sprint(span.ParentID),
+	})
+	if existing, ok := metadata.FromContext(ctx); ok {
+		md = metadata.Join(existing, md)
+	}
+	return metadata.NewContext(ctx, md)
+}
+
+// getIDs will return ids embededd an ahe context.
+func getIDs(ctx context.Context) (traceID, parentID uint64) {
+	if md, ok := metadata.FromContext(ctx); ok {
+		if id := getID(md, traceIDKey); id > 0 {
+			traceID = id
+		}
+		if id := getID(md, parentIDKey); id > 0 {
+			parentID = id
+		}
+	}
+	return traceID, parentID
+}
+
+// getID parses an id from the metadata.
+func getID(md metadata.MD, name string) uint64 {
+	for _, str := range md[name] {
+		id, err := strconv.Atoi(str)
+		if err == nil {
+			return uint64(id)
+		}
+	}
+	return 0
+}