SRE-3 disable otel streaminginterceptor (#49)

This is generating so many events in cacher it's destroying our tracing budget.

The data generated didn't seem very useful either so let's disable by
default and turn it on on a case-by-case basis.

Signed-off-by: Amy Tobey <atobey@equinix.com>

Author: Amy Tobey

grpc/grpc.go

@@ -50,6 +50,7 @@ type Option func(*Server)
 // A tls server is setup if keys are provided in either the environment variables GRPC_CERT/GRPC_KEY, or using the X509KeyPair or LoadX509KeyPair helper funcs.
 // Logging is always setup using the provided log.Logger.
 // Prometheus is always setup using the default prom interceptors and Register func.
+// OpenTelemetry is setup for unary servers, but NOT streaming servers. Use StreamingInterceptor to add it if you really want/need it.
 //
 // req is called after the server has been setup.
 // This is where your service is gets registered with grpc, equivalent to pb.RegisterMyServiceServer(s, &myServiceImpl{}).
@@ -62,7 +63,6 @@ func NewServer(l log.Logger, reg ServiceRegister, options ...Option) (*Server, e
 	s.streamers = append(s.streamers,
 		logStream,
 		grpc_prometheus.StreamServerInterceptor,
-		otelgrpc.StreamServerInterceptor(),
 	)
 	s.unariers = append(s.unariers,
 		logUnary,
@@ -260,7 +260,8 @@ func LoadX509KeyPair(certFile, keyFile string) Option {
 }
 
 // StreamInterceptor adds the argument to the list of interceptors in a grpc_middleware.Chain
-// Logging, Prometheus, and OpenTelemetry interceptors are always included in the set
+// Logging and Prometheus interceptors are always included in the set. OpenTelemetry is NOT
+// included by default on streams because it's noisy and can't be on by default.
 func StreamInterceptor(si grpc.StreamServerInterceptor) Option {
 	return func(s *Server) {
 		s.streamers = append(s.streamers, si)