stats/opentelemetry: Add CSM Observability API

stats/opentelemetry/csm/observability.go

@@ -0,0 +1,95 @@
+/*
+ *
+ * Copyright 2024 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package csm
+
+import (
+	"context"
+	"net/url"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/internal"
+	"google.golang.org/grpc/stats/opentelemetry"
+	otelinternal "google.golang.org/grpc/stats/opentelemetry/internal"
+)
+
+var clientSideOTelWithCSM grpc.DialOption
+var clientSideOTel grpc.DialOption
+
+// Observability sets up CSM Observability for the binary globally. It sets up
+// two client side OpenTelemetry instrumentation components configured with the
+// provided options, one with a CSM Plugin Option configured, one without.
+// Created channels will pick up one of these dependent on whether channels are
+// CSM Channels or not, which is derived from the Channel's parsed target after
+// dialing.
+//
+// It sets up a server side OpenTelemetry instrumentation component configured
+// with options provided alongside a CSM Plugin Option to be registered globally
+// and picked up for every server.
+//
+// The CSM Plugin Option is instantiated with local labels and metadata exchange
+// labels pulled from the environment, and emits metadata exchange labels from
+// the peer and local labels. Context timeouts do not trigger an error, but set
+// certain labels to "unknown".
+//
+// This function is not thread safe, and should only be invoked once in main
+// before any channels or servers are created. Returns a cleanup function to be
+// deferred in main.
+func Observability(ctx context.Context, options opentelemetry.Options) func() {
+	csmPluginOption := newPluginOption(ctx)
+	clientSideOTelWithCSM = dialOptionWithCSMPluginOption(options, csmPluginOption)
+	clientSideOTel = opentelemetry.DialOption(options)
+
+	serverSideOTelWithCSM := serverOptionWithCSMPluginOption(options, csmPluginOption)
+
+	internal.AddGlobalPerTargetDialOptions.(func(opt any))(perTargetDialOption{})
+
+	internal.AddGlobalServerOptions.(func(opt ...grpc.ServerOption))(serverSideOTelWithCSM)
+
+	return func() {
+		internal.ClearGlobalServerOptions()
+		internal.ClearGlobalPerTargetDialOptions()
+	}
+} // fail, can run it locally and on cloudtop, replace to point to this stats/opentelemetry (replace grpc or something else)?
+
+// make it's own go mod
+// go get a random version using hash
+// then replace
+// try and build docker image using that docker run thing, this is the hook into interop scripts...
+
+// replace grpc module and otel module I guess
+
+type perTargetDialOption struct {}
+
+func (perTargetDialOption) DialOptionForTarget(parsedTarget url.URL) grpc.DialOption {
+	if determineTargetCSM(&parsedTarget) {
+		return clientSideOTelWithCSM
+	}
+	return clientSideOTel
+}
+
+func dialOptionWithCSMPluginOption(options opentelemetry.Options, po otelinternal.PluginOption) grpc.DialOption {
+	options.MetricsOptions.OptionalLabels = []string{"csm.service_name", "csm.service_namespace_name"} // Attach the two xDS Optional Labels for this component to not filter out.
+	otelinternal.SetPluginOption.(func(options *opentelemetry.Options, po otelinternal.PluginOption))(&options, po)
+	return opentelemetry.DialOption(options)
+}
+
+func serverOptionWithCSMPluginOption(options opentelemetry.Options, po otelinternal.PluginOption) grpc.ServerOption {
+	otelinternal.SetPluginOption.(func(options *opentelemetry.Options, po otelinternal.PluginOption))(&options, po)
+	return opentelemetry.ServerOption(options)
+}

stats/opentelemetry/internal/pluginoption.go

@@ -21,6 +21,9 @@ import (
 	"google.golang.org/grpc/metadata"
 )
 
+// SetPluginOption sets the plugin option on Options.
+var SetPluginOption any // func(*Options, PluginOption)
+
 // PluginOption is the interface which represents a plugin option for the
 // OpenTelemetry instrumentation component. This plugin option emits labels from
 // metadata and also creates metadata containing labels. These labels are

stats/opentelemetry/opentelemetry.go

@@ -33,6 +33,13 @@ import (
 	"go.opentelemetry.io/otel/metric/noop"
 )
 
+func init() {
+	otelinternal.SetPluginOption = func(o *Options, po otelinternal.PluginOption) {
+		o.MetricsOptions.pluginOption = po
+	}
+}
+
+
 var logger = grpclog.Component("otel-plugin")
 
 var canonicalString = internal.CanonicalString.(func(codes.Code) string)