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68 lines
1.9 KiB
Go
68 lines
1.9 KiB
Go
package tracing
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// Copyright 2018 Microsoft Corporation
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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import (
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"context"
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"net/http"
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)
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// Tracer represents an HTTP tracing facility.
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type Tracer interface {
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NewTransport(base *http.Transport) http.RoundTripper
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StartSpan(ctx context.Context, name string) context.Context
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EndSpan(ctx context.Context, httpStatusCode int, err error)
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}
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var (
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tracer Tracer
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)
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// Register will register the provided Tracer. Pass nil to unregister a Tracer.
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func Register(t Tracer) {
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tracer = t
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}
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// IsEnabled returns true if a Tracer has been registered.
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func IsEnabled() bool {
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return tracer != nil
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}
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// NewTransport creates a new instrumenting http.RoundTripper for the
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// registered Tracer. If no Tracer has been registered it returns nil.
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func NewTransport(base *http.Transport) http.RoundTripper {
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if tracer != nil {
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return tracer.NewTransport(base)
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}
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return nil
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}
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// StartSpan starts a trace span with the specified name, associating it with the
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// provided context. Has no effect if a Tracer has not been registered.
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func StartSpan(ctx context.Context, name string) context.Context {
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if tracer != nil {
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return tracer.StartSpan(ctx, name)
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}
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return ctx
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}
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// EndSpan ends a previously started span stored in the context.
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// Has no effect if a Tracer has not been registered.
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func EndSpan(ctx context.Context, httpStatusCode int, err error) {
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if tracer != nil {
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tracer.EndSpan(ctx, httpStatusCode, err)
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}
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}
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