peridot/vendor/go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp/wrap.go

100 lines
2.4 KiB
Go
Raw Normal View History

// Copyright The OpenTelemetry Authors
// SPDX-License-Identifier: Apache-2.0
package otelhttp // import "go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
import (
"context"
"io"
"net/http"
"sync/atomic"
"go.opentelemetry.io/otel/propagation"
)
var _ io.ReadCloser = &bodyWrapper{}
// bodyWrapper wraps a http.Request.Body (an io.ReadCloser) to track the number
// of bytes read and the last error.
type bodyWrapper struct {
io.ReadCloser
record func(n int64) // must not be nil
read atomic.Int64
err error
}
func (w *bodyWrapper) Read(b []byte) (int, error) {
n, err := w.ReadCloser.Read(b)
n1 := int64(n)
w.read.Add(n1)
w.err = err
w.record(n1)
return n, err
}
func (w *bodyWrapper) Close() error {
return w.ReadCloser.Close()
}
var _ http.ResponseWriter = &respWriterWrapper{}
// respWriterWrapper wraps a http.ResponseWriter in order to track the number of
// bytes written, the last error, and to catch the first written statusCode.
// TODO: The wrapped http.ResponseWriter doesn't implement any of the optional
// types (http.Hijacker, http.Pusher, http.CloseNotifier, http.Flusher, etc)
// that may be useful when using it in real life situations.
type respWriterWrapper struct {
http.ResponseWriter
record func(n int64) // must not be nil
// used to inject the header
ctx context.Context
props propagation.TextMapPropagator
written int64
statusCode int
err error
wroteHeader bool
}
func (w *respWriterWrapper) Header() http.Header {
return w.ResponseWriter.Header()
}
func (w *respWriterWrapper) Write(p []byte) (int, error) {
if !w.wroteHeader {
w.WriteHeader(http.StatusOK)
}
n, err := w.ResponseWriter.Write(p)
n1 := int64(n)
w.record(n1)
w.written += n1
w.err = err
return n, err
}
// WriteHeader persists initial statusCode for span attribution.
// All calls to WriteHeader will be propagated to the underlying ResponseWriter
// and will persist the statusCode from the first call.
// Blocking consecutive calls to WriteHeader alters expected behavior and will
// remove warning logs from net/http where developers will notice incorrect handler implementations.
func (w *respWriterWrapper) WriteHeader(statusCode int) {
if !w.wroteHeader {
w.wroteHeader = true
w.statusCode = statusCode
}
w.ResponseWriter.WriteHeader(statusCode)
}
func (w *respWriterWrapper) Flush() {
if !w.wroteHeader {
w.WriteHeader(http.StatusOK)
}
if f, ok := w.ResponseWriter.(http.Flusher); ok {
f.Flush()
}
}