bump go-grpc-prometheus since 1.2.0 actually exposes the metrics

v1.1.0 (which is what we currently use), does not expose metrics which
makes it impossible to migrate.

vendor/github.com/grpc-ecosystem/go-grpc-prometheus/client.go

@@ -6,67 +6,34 @@
 package grpc_prometheus
 
 import (
-	"io"
-
-	"golang.org/x/net/context"
-	"google.golang.org/grpc"
-	"google.golang.org/grpc/codes"
+	prom "github.com/prometheus/client_golang/prometheus"
 )
 
-// UnaryClientInterceptor is a gRPC client-side interceptor that provides Prometheus monitoring for Unary RPCs.
-func UnaryClientInterceptor(ctx context.Context, method string, req, reply interface{}, cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error {
-	monitor := newClientReporter(Unary, method)
-	monitor.SentMessage()
-	err := invoker(ctx, method, req, reply, cc, opts...)
-	if err != nil {
-		monitor.ReceivedMessage()
-	}
-	monitor.Handled(grpc.Code(err))
-	return err
+var (
+	// DefaultClientMetrics is the default instance of ClientMetrics. It is
+	// intended to be used in conjunction the default Prometheus metrics
+	// registry.
+	DefaultClientMetrics = NewClientMetrics()
+
+	// UnaryClientInterceptor is a gRPC client-side interceptor that provides Prometheus monitoring for Unary RPCs.
+	UnaryClientInterceptor = DefaultClientMetrics.UnaryClientInterceptor()
+
+	// StreamClientInterceptor is a gRPC client-side interceptor that provides Prometheus monitoring for Streaming RPCs.
+	StreamClientInterceptor = DefaultClientMetrics.StreamClientInterceptor()
+)
+
+func init() {
+	prom.MustRegister(DefaultClientMetrics.clientStartedCounter)
+	prom.MustRegister(DefaultClientMetrics.clientHandledCounter)
+	prom.MustRegister(DefaultClientMetrics.clientStreamMsgReceived)
+	prom.MustRegister(DefaultClientMetrics.clientStreamMsgSent)
 }
 
-// StreamServerInterceptor is a gRPC client-side interceptor that provides Prometheus monitoring for Streaming RPCs.
-func StreamClientInterceptor(ctx context.Context, desc *grpc.StreamDesc, cc *grpc.ClientConn, method string, streamer grpc.Streamer, opts ...grpc.CallOption) (grpc.ClientStream, error) {
-	monitor := newClientReporter(clientStreamType(desc), method)
-	clientStream, err := streamer(ctx, desc, cc, method, opts...)
-	if err != nil {
-		monitor.Handled(grpc.Code(err))
-		return nil, err
-	}
-	return &monitoredClientStream{clientStream, monitor}, nil
-}
-
-func clientStreamType(desc *grpc.StreamDesc) grpcType {
-	if desc.ClientStreams && !desc.ServerStreams {
-		return ClientStream
-	} else if !desc.ClientStreams && desc.ServerStreams {
-		return ServerStream
-	}
-	return BidiStream
-}
-
-// monitoredClientStream wraps grpc.ClientStream allowing each Sent/Recv of message to increment counters.
-type monitoredClientStream struct {
-	grpc.ClientStream
-	monitor *clientReporter
-}
-
-func (s *monitoredClientStream) SendMsg(m interface{}) error {
-	err := s.ClientStream.SendMsg(m)
-	if err == nil {
-		s.monitor.SentMessage()
-	}
-	return err
-}
-
-func (s *monitoredClientStream) RecvMsg(m interface{}) error {
-	err := s.ClientStream.RecvMsg(m)
-	if err == nil {
-		s.monitor.ReceivedMessage()
-	} else if err == io.EOF {
-		s.monitor.Handled(codes.OK)
-	} else {
-		s.monitor.Handled(grpc.Code(err))
-	}
-	return err
+// EnableClientHandlingTimeHistogram turns on recording of handling time of
+// RPCs. Histogram metrics can be very expensive for Prometheus to retain and
+// query. This function acts on the DefaultClientMetrics variable and the
+// default Prometheus metrics registry.
+func EnableClientHandlingTimeHistogram(opts ...HistogramOption) {
+	DefaultClientMetrics.EnableClientHandlingTimeHistogram(opts...)
+	prom.Register(DefaultClientMetrics.clientHandledHistogram)
 }