otelgrpc: Add Filter for stats handler (open-telemetry#5196)

* otelgrpc: Add filter for stats handler

* Add entries to CHANGELOG

* fix CHANGELOG

* keep Deprecated comment of `WithInterceptorFilter`

* deprecate `InterceptorFilter` type

* change the location of `gctx.record` nil check location to reduce heap allocations

* add documentation for filters and interceptor packages

* fix the location of entries in CHANGELOG

* more reasonable doc comment for interceptor package

Co-authored-by: Robert Pająk <pellared@hotmail.com>

* more reasonable doc comment for interceptor package

Co-authored-by: Robert Pająk <pellared@hotmail.com>

* Use more appropriate word in the comment of InterceptorFilter

Co-authored-by: Robert Pająk <pellared@hotmail.com>

* more reasonable doc comment for filters package

Co-authored-by: Robert Pająk <pellared@hotmail.com>

* fix the comment of `Filter`

* Clearly describe the effects of the change

* add tests for `stats_handler.go`

---------

Co-authored-by: David Ashpole <dashpole@google.com>
Co-authored-by: Robert Pająk <pellared@hotmail.com>
Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>

CHANGELOG.md

@@ -15,6 +15,17 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
   - `prometheus` and `none` are supported values. You can specify multiple producers separated by a comma.
   - Add `WithFallbackMetricProducer` option that adds a fallback if the `OTEL_METRICS_PRODUCERS` is not set or empty.
 - The `go.opentelemetry.io/contrib/processors/baggage/baggagetrace` module. This module provides a Baggage Span Processor. (#5404)
+- Add gRPC trace `Filter` for stats handler to `go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc`. (#5196)
+
+### Changed
+
+- The gRPC trace `Filter` for interceptor is renamed to `InterceptorFilter`. (#5196)
+- The gRPC trace filter functions `Any`, `All`, `None`, `Not`, `MethodName`, `MethodPrefix`, `FullMethodName`, `ServiceName`, `ServicePrefix` and `HealthCheck` for interceptor are moved to `go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc/filters/interceptor`.
+  With this change, the filters in `go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc` are now working for stats handler. (#5196)
+
+### Deprecated
+
+- The `InterceptorFilter` type in `go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc` is deprecated. (#5196)
 
 ### Fixed
 

instrumentation/google.golang.org/grpc/otelgrpc/config.go

@@ -4,6 +4,8 @@
 package otelgrpc // import "go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
 
 import (
+	"google.golang.org/grpc/stats"
+
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/metric"
@@ -20,18 +22,26 @@ const (
 	GRPCStatusCodeKey = attribute.Key("rpc.grpc.status_code")
 )
 
-// Filter is a predicate used to determine whether a given request in
-// interceptor info should be traced. A Filter must return true if
+// InterceptorFilter is a predicate used to determine whether a given request in
+// interceptor info should be instrumented. A InterceptorFilter must return true if
 // the request should be traced.
-type Filter func(*InterceptorInfo) bool
+//
+// Deprecated: Use stats handlers instead.
+type InterceptorFilter func(*InterceptorInfo) bool
+
+// Filter is a predicate used to determine whether a given request in
+// should be instrumented by the attatched RPC tag info.
+// A Filter must return true if the request should be instrumented.
+type Filter func(*stats.RPCTagInfo) bool
 
 // config is a group of options for this instrumentation.
 type config struct {
-	Filter           Filter
-	Propagators      propagation.TextMapPropagator
-	TracerProvider   trace.TracerProvider
-	MeterProvider    metric.MeterProvider
-	SpanStartOptions []trace.SpanStartOption
+	Filter            Filter
+	InterceptorFilter InterceptorFilter
+	Propagators       propagation.TextMapPropagator
+	TracerProvider    trace.TracerProvider
+	MeterProvider     metric.MeterProvider
+	SpanStartOptions  []trace.SpanStartOption
 
 	ReceivedEvent bool
 	SentEvent     bool
@@ -152,15 +162,30 @@ func (o tracerProviderOption) apply(c *config) {
 // WithInterceptorFilter returns an Option to use the request filter.
 //
 // Deprecated: Use stats handlers instead.
-func WithInterceptorFilter(f Filter) Option {
+func WithInterceptorFilter(f InterceptorFilter) Option {
 	return interceptorFilterOption{f: f}
 }
 
 type interceptorFilterOption struct {
-	f Filter
+	f InterceptorFilter
 }
 
 func (o interceptorFilterOption) apply(c *config) {
+	if o.f != nil {
+		c.InterceptorFilter = o.f
+	}
+}
+
+// WithFilter returns an Option to use the request filter.
+func WithFilter(f Filter) Option {
+	return filterOption{f: f}
+}
+
+type filterOption struct {
+	f Filter
+}
+
+func (o filterOption) apply(c *config) {
 	if o.f != nil {
 		c.Filter = o.f
 	}

instrumentation/google.golang.org/grpc/otelgrpc/filters/filters.go

@@ -1,12 +1,16 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
+// Package filters provides a set of filters useful with the
+// [otelgrpc.WithFilter] option to control which inbound requests are instrumented.
 package filters // import "go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc/filters"
 
 import (
 	"path"
 	"strings"
 
+	"google.golang.org/grpc/stats"
+
 	"go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
 )
 
@@ -19,20 +23,8 @@ type gRPCPath struct {
 // and returns as gRPCPath object that has divided service and method names
 // https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md
 // If name is not FullMethod, returned gRPCPath has empty service field.
-func splitFullMethod(i *otelgrpc.InterceptorInfo) gRPCPath {
-	var name string
-	switch i.Type {
-	case otelgrpc.UnaryServer:
-		name = i.UnaryServerInfo.FullMethod
-	case otelgrpc.StreamServer:
-		name = i.StreamServerInfo.FullMethod
-	case otelgrpc.UnaryClient, otelgrpc.StreamClient:
-		name = i.Method
-	default:
-		name = i.Method
-	}
-
-	s, m := path.Split(name)
+func splitFullMethod(i *stats.RPCTagInfo) gRPCPath {
+	s, m := path.Split(i.FullMethodName)
 	if s != "" {
 		s = path.Clean(s)
 		s = strings.TrimLeft(s, "/")
@@ -47,7 +39,7 @@ func splitFullMethod(i *otelgrpc.InterceptorInfo) gRPCPath {
 // Any takes a list of Filters and returns a Filter that
 // returns true if any Filter in the list returns true.
 func Any(fs ...otelgrpc.Filter) otelgrpc.Filter {
-	return func(i *otelgrpc.InterceptorInfo) bool {
+	return func(i *stats.RPCTagInfo) bool {
 		for _, f := range fs {
 			if f(i) {
 				return true
@@ -60,7 +52,7 @@ func Any(fs ...otelgrpc.Filter) otelgrpc.Filter {
 // All takes a list of Filters and returns a Filter that
 // returns true only if all Filters in the list return true.
 func All(fs ...otelgrpc.Filter) otelgrpc.Filter {
-	return func(i *otelgrpc.InterceptorInfo) bool {
+	return func(i *stats.RPCTagInfo) bool {
 		for _, f := range fs {
 			if !f(i) {
 				return false
@@ -78,15 +70,15 @@ func None(fs ...otelgrpc.Filter) otelgrpc.Filter {
 
 // Not provides a convenience mechanism for inverting a Filter.
 func Not(f otelgrpc.Filter) otelgrpc.Filter {
-	return func(i *otelgrpc.InterceptorInfo) bool {
+	return func(i *stats.RPCTagInfo) bool {
 		return !f(i)
 	}
 }
 
 // MethodName returns a Filter that returns true if the request's
 // method name matches the provided string n.
 func MethodName(n string) otelgrpc.Filter {
-	return func(i *otelgrpc.InterceptorInfo) bool {
+	return func(i *stats.RPCTagInfo) bool {
 		p := splitFullMethod(i)
 		return p.method == n
 	}
@@ -95,7 +87,7 @@ func MethodName(n string) otelgrpc.Filter {
 // MethodPrefix returns a Filter that returns true if the request's
 // method starts with the provided string pre.
 func MethodPrefix(pre string) otelgrpc.Filter {
-	return func(i *otelgrpc.InterceptorInfo) bool {
+	return func(i *stats.RPCTagInfo) bool {
 		p := splitFullMethod(i)
 		return strings.HasPrefix(p.method, pre)
 	}
@@ -105,26 +97,15 @@ func MethodPrefix(pre string) otelgrpc.Filter {
 // full RPC method string, i.e. /package.service/method, starts with
 // the provided string n.
 func FullMethodName(n string) otelgrpc.Filter {
-	return func(i *otelgrpc.InterceptorInfo) bool {
-		var fm string
-		switch i.Type {
-		case otelgrpc.UnaryClient, otelgrpc.StreamClient:
-			fm = i.Method
-		case otelgrpc.UnaryServer:
-			fm = i.UnaryServerInfo.FullMethod
-		case otelgrpc.StreamServer:
-			fm = i.StreamServerInfo.FullMethod
-		default:
-			fm = i.Method
-		}
-		return fm == n
+	return func(i *stats.RPCTagInfo) bool {
+		return i.FullMethodName == n
 	}
 }
 
 // ServiceName returns a Filter that returns true if the request's
 // service name, i.e. package.service, matches s.
 func ServiceName(s string) otelgrpc.Filter {
-	return func(i *otelgrpc.InterceptorInfo) bool {
+	return func(i *stats.RPCTagInfo) bool {
 		p := splitFullMethod(i)
 		return p.service == s
 	}
@@ -133,7 +114,7 @@ func ServiceName(s string) otelgrpc.Filter {
 // ServicePrefix returns a Filter that returns true if the request's
 // service name, i.e. package.service, starts with the provided string pre.
 func ServicePrefix(pre string) otelgrpc.Filter {
-	return func(i *otelgrpc.InterceptorInfo) bool {
+	return func(i *stats.RPCTagInfo) bool {
 		p := splitFullMethod(i)
 		return strings.HasPrefix(p.service, pre)
 	}