Move tracing grpc code to the trace package

Signed-off-by: Andres Taylor <antaylor@squareup.com>

go/trace/trace.go

@@ -24,8 +24,10 @@ import (
 	"io"
 	"strings"
 
+	"github.com/opentracing-contrib/go-grpc"
 	"github.com/opentracing/opentracing-go"
 	"golang.org/x/net/context"
+	"google.golang.org/grpc"
 	"vitess.io/vitess/go/vt/log"
 	"vitess.io/vitess/go/vt/proto/vtrpc"
 	"vitess.io/vitess/go/vt/vterrors"
@@ -80,6 +82,30 @@ func CopySpan(parentCtx, spanCtx context.Context) context.Context {
 	return parentCtx
 }
 
+func GetGrpcClientOptions() []grpc.DialOption {
+	tracer := opentracing.GlobalTracer()
+	_, isNoopTracer := tracer.(opentracing.NoopTracer)
+	if isNoopTracer {
+		return []grpc.DialOption{}
+
+	} else {
+		return []grpc.DialOption{
+			grpc.WithUnaryInterceptor(otgrpc.OpenTracingClientInterceptor(tracer)),
+			grpc.WithStreamInterceptor(otgrpc.OpenTracingStreamClientInterceptor(tracer)),
+		}
+	}
+}
+
+func AddGrpcServerOptions(addInterceptors func(s grpc.StreamServerInterceptor, u grpc.UnaryServerInterceptor)) {
+	tracer := opentracing.GlobalTracer()
+	_, isNoopTracer := tracer.(*opentracing.NoopTracer)
+	if isNoopTracer {
+		return
+	}
+
+	addInterceptors(otgrpc.OpenTracingStreamServerInterceptor(tracer), otgrpc.OpenTracingServerInterceptor(tracer))
+}
+
 // SpanFactory is an interface for creating spans or extracting them from Contexts.
 type SpanFactory interface {
 	// New creates a new span from an existing one, if provided. The parent can also be nil

go/vt/grpcclient/client.go

@@ -21,11 +21,10 @@ package grpcclient
 import (
 	"flag"
 
-	"github.com/opentracing-contrib/go-grpc"
-	"github.com/opentracing/opentracing-go"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/keepalive"
+	"vitess.io/vitess/go/trace"
 
 	"github.com/grpc-ecosystem/go-grpc-prometheus"
 
@@ -100,13 +99,7 @@ func Dial(target string, failFast FailFast, opts ...grpc.DialOption) (*grpc.Clie
 		newopts = append(newopts, grpc.WithStreamInterceptor(grpc_prometheus.StreamClientInterceptor))
 	}
 
-	// Enable trace information, if we have a real tracer
-	tracer := opentracing.GlobalTracer()
-	_, isNoopTracer := tracer.(opentracing.NoopTracer)
-	if !isNoopTracer {
-		newopts = append(newopts, grpc.WithUnaryInterceptor(otgrpc.OpenTracingClientInterceptor(tracer)))
-		newopts = append(newopts, grpc.WithStreamInterceptor(otgrpc.OpenTracingStreamClientInterceptor(tracer)))
-	}
+	newopts = append(newopts, trace.GetGrpcClientOptions()...)
 
 	return grpc.Dial(target, newopts...)
 }

go/vt/schemamanager/schemaswap/schema_swap.go

@@ -308,7 +308,7 @@ func (schemaSwap *Swap) executeSwap() error {
 	}
 	errHealthWatchers := schemaSwap.runOnAllShards(
 		func(shard *shardSchemaSwap) error {
-			return shard.startHealthWatchers(schemaSwap.ctx )
+			return shard.startHealthWatchers(schemaSwap.ctx)
 		})
 	// Note: this defer statement is before the error is checked because some shards may
 	// succeed while others fail. We should try to stop health watching on all shards no

go/vt/servenv/grpc_server.go

@@ -25,8 +25,7 @@ import (
 
 	"github.com/grpc-ecosystem/go-grpc-middleware"
 	"github.com/grpc-ecosystem/go-grpc-prometheus"
-	"github.com/opentracing-contrib/go-grpc"
-	"github.com/opentracing/opentracing-go"
+	"vitess.io/vitess/go/trace"
 
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/credentials"
@@ -194,11 +193,7 @@ func interceptors() []grpc.ServerOption {
 		interceptors.Add(grpc_prometheus.StreamServerInterceptor, grpc_prometheus.UnaryServerInterceptor)
 	}
 
-	tracer := opentracing.GlobalTracer()
-	_, isNoopTracer := tracer.(*opentracing.NoopTracer)
-	if !isNoopTracer {
-		interceptors.Add(otgrpc.OpenTracingStreamServerInterceptor(tracer), otgrpc.OpenTracingServerInterceptor(tracer))
-	}
+	trace.AddGrpcServerOptions(interceptors.Add)
 
 	if interceptors.NonEmpty() {
 		return []grpc.ServerOption{