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opentelemetry-go/instrumentation/grpctrace/grpctrace.go

96 lines
2.7 KiB
Go

// 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 grpctrace
import (
"context"
"google.golang.org/grpc/metadata"
"go.opentelemetry.io/otel/api/correlation"
"go.opentelemetry.io/otel/api/global"
"go.opentelemetry.io/otel/api/kv"
"go.opentelemetry.io/otel/api/propagation"
"go.opentelemetry.io/otel/api/trace"
)
// Option is a function that allows configuration of the grpctrace Extract()
// and Inject() functions
type Option func(*config)
type config struct {
propagators propagation.Propagators
}
func newConfig(opts []Option) *config {
c := &config{propagators: global.Propagators()}
for _, o := range opts {
o(c)
}
return c
}
// WithPropagators sets the propagators to use for Extraction and Injection
func WithPropagators(props propagation.Propagators) Option {
return func(c *config) {
c.propagators = props
}
}
type metadataSupplier struct {
metadata *metadata.MD
}
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)
}
// 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)
propagation.InjectHTTP(ctx, c.propagators, &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) ([]kv.KeyValue, trace.SpanContext) {
c := newConfig(opts)
ctx = propagation.ExtractHTTP(ctx, c.propagators, &metadataSupplier{
metadata: metadata,
})
spanContext := trace.RemoteSpanContextFromContext(ctx)
var correlationCtxKVs []kv.KeyValue
correlation.MapFromContext(ctx).Foreach(func(kv kv.KeyValue) bool {
correlationCtxKVs = append(correlationCtxKVs, kv)
return true
})
return correlationCtxKVs, spanContext
}