99 lines
2.8 KiB
Go
99 lines
2.8 KiB
Go
// Copyright The OpenTelemetry Authors
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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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package otelhttp // import "go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
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import (
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"context"
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"io"
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"net/http"
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"go.opentelemetry.io/otel/propagation"
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)
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var _ io.ReadCloser = &bodyWrapper{}
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// bodyWrapper wraps a http.Request.Body (an io.ReadCloser) to track the number
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// of bytes read and the last error.
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type bodyWrapper struct {
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io.ReadCloser
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record func(n int64) // must not be nil
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read int64
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err error
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}
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func (w *bodyWrapper) Read(b []byte) (int, error) {
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n, err := w.ReadCloser.Read(b)
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n1 := int64(n)
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w.read += n1
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w.err = err
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w.record(n1)
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return n, err
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}
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func (w *bodyWrapper) Close() error {
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return w.ReadCloser.Close()
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}
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var _ http.ResponseWriter = &respWriterWrapper{}
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// respWriterWrapper wraps a http.ResponseWriter in order to track the number of
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// bytes written, the last error, and to catch the first written statusCode.
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// TODO: The wrapped http.ResponseWriter doesn't implement any of the optional
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// types (http.Hijacker, http.Pusher, http.CloseNotifier, http.Flusher, etc)
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// that may be useful when using it in real life situations.
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type respWriterWrapper struct {
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http.ResponseWriter
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record func(n int64) // must not be nil
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// used to inject the header
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ctx context.Context
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props propagation.TextMapPropagator
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written int64
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statusCode int
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err error
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wroteHeader bool
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}
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func (w *respWriterWrapper) Header() http.Header {
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return w.ResponseWriter.Header()
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}
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func (w *respWriterWrapper) Write(p []byte) (int, error) {
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if !w.wroteHeader {
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w.WriteHeader(http.StatusOK)
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}
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n, err := w.ResponseWriter.Write(p)
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n1 := int64(n)
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w.record(n1)
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w.written += n1
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w.err = err
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return n, err
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}
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// WriteHeader persists initial statusCode for span attribution.
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// All calls to WriteHeader will be propagated to the underlying ResponseWriter
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// and will persist the statusCode from the first call.
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// Blocking consecutive calls to WriteHeader alters expected behavior and will
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// remove warning logs from net/http where developers will notice incorrect handler implementations.
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func (w *respWriterWrapper) WriteHeader(statusCode int) {
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if !w.wroteHeader {
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w.wroteHeader = true
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w.statusCode = statusCode
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}
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w.ResponseWriter.WriteHeader(statusCode)
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}
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