/
grpctrace.go
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/
grpctrace.go
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// Copyright The OpenTelemetry 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 otelgrpc
import (
"context"
"google.golang.org/grpc/metadata"
"go.opentelemetry.io/otel"
"go.opentelemetry.io/otel/attribute"
"go.opentelemetry.io/otel/baggage"
"go.opentelemetry.io/otel/propagation"
"go.opentelemetry.io/otel/trace"
)
const (
// instrumentationName is the name of this instrumentation package.
instrumentationName = "go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
// GRPCStatusCodeKey is convention for numeric status code of a gRPC request.
GRPCStatusCodeKey = attribute.Key("rpc.grpc.status_code")
)
// config is a group of options for this instrumentation.
type config struct {
Propagators propagation.TextMapPropagator
TracerProvider trace.TracerProvider
}
// Option applies an option value for a config.
type Option interface {
apply(*config)
}
// newConfig returns a config configured with all the passed Options.
func newConfig(opts []Option) *config {
c := &config{
Propagators: otel.GetTextMapPropagator(),
TracerProvider: otel.GetTracerProvider(),
}
for _, o := range opts {
o.apply(c)
}
return c
}
type propagatorsOption struct{ p propagation.TextMapPropagator }
func (o propagatorsOption) apply(c *config) {
if o.p != nil {
c.Propagators = o.p
}
}
// WithPropagators returns an Option to use the Propagators when extracting
// and injecting trace context from requests.
func WithPropagators(p propagation.TextMapPropagator) Option {
return propagatorsOption{p: p}
}
type tracerProviderOption struct{ tp trace.TracerProvider }
func (o tracerProviderOption) apply(c *config) {
if o.tp != nil {
c.TracerProvider = o.tp
}
}
// WithTracerProvider returns an Option to use the TracerProvider when
// creating a Tracer.
func WithTracerProvider(tp trace.TracerProvider) Option {
return tracerProviderOption{tp: tp}
}
type metadataSupplier struct {
metadata *metadata.MD
}
// assert that metadataSupplier implements the TextMapCarrier interface
var _ propagation.TextMapCarrier = &metadataSupplier{}
func (s *metadataSupplier) Get(key string) string {
values := s.metadata.Get(key)
if len(values) == 0 {
return ""
}
return values[0]
}
func (s *metadataSupplier) Set(key string, value string) {
s.metadata.Set(key, value)
}
func (s *metadataSupplier) Keys() []string {
out := make([]string, 0, len(*s.metadata))
for key := range *s.metadata {
out = append(out, key)
}
return out
}
// Inject injects correlation context and span context into the gRPC
// metadata object. This function is meant to be used on outgoing
// requests.
func Inject(ctx context.Context, metadata *metadata.MD, opts ...Option) {
c := newConfig(opts)
c.Propagators.Inject(ctx, &metadataSupplier{
metadata: metadata,
})
}
// Extract returns the correlation context and span context that
// another service encoded in the gRPC metadata object with Inject.
// This function is meant to be used on incoming requests.
func Extract(ctx context.Context, metadata *metadata.MD, opts ...Option) (baggage.Baggage, trace.SpanContext) {
c := newConfig(opts)
ctx = c.Propagators.Extract(ctx, &metadataSupplier{
metadata: metadata,
})
return baggage.FromContext(ctx), trace.SpanContextFromContext(ctx)
}