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opentelemetry-go/plugin/othttp/wrap.go
Edward Muller d351eb4de2 Http interceptors (#156)
* WIP

* Finish http middleware implementation

This is currently done as httptrace.NewHandler(). This should maybe
be moved to a different package or renamed, but atm this name
seemed the least objectionable to me.

There are a few TODOs sprinkled in the code for questions I didn't
know the answers to.

There is an example provided, which when copied to a main func
locally work against the jaeger all in one.

Real tests need to be added.

* Address feedback

* Tie in propagation, update attributes, more options, revise example, etc.

Dropped the httpConfig type because it seemed redundant an unecessary
abstraction.

* WithRouteTag

* address out of band feedback

* move to othttp package

* Add a very basic test.

I ended up needing to export the Traceparentheader const so that
it was accessible to this test.

* Add file header
2019-10-07 10:25:11 -07:00

83 lines
2.1 KiB
Go

// Copyright 2019, 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 othttp
import (
"io"
"net/http"
)
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 int) // must not be nil
read int64
err error
}
func (w *bodyWrapper) Read(b []byte) (int, error) {
n, err := w.ReadCloser.Read(b)
w.read += int64(n)
w.err = err
w.record(n)
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 returned 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 int) // must not be nil
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)
w.wroteHeader = true
}
n, err := w.ResponseWriter.Write(p)
w.record(n)
w.written += int64(n)
w.err = err
return n, err
}
func (w *respWriterWrapper) WriteHeader(statusCode int) {
w.wroteHeader = true
w.statusCode = statusCode
w.ResponseWriter.WriteHeader(statusCode)
}