mirror of
https://github.com/octoleo/restic.git
synced 2024-11-23 05:12:10 +00:00
108 lines
3.2 KiB
Go
108 lines
3.2 KiB
Go
// Copyright 2017 Google Inc. All Rights Reserved.
|
|
//
|
|
// 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.
|
|
|
|
// +build go1.7
|
|
|
|
package trace
|
|
|
|
import (
|
|
"net/http"
|
|
)
|
|
|
|
// Transport is an http.RoundTripper that traces the outgoing requests.
|
|
//
|
|
// Transport is safe for concurrent usage.
|
|
type Transport struct {
|
|
// Base is the base http.RoundTripper to be used to do the actual request.
|
|
//
|
|
// Optional. If nil, http.DefaultTransport is used.
|
|
Base http.RoundTripper
|
|
}
|
|
|
|
// RoundTrip creates a trace.Span and inserts it into the outgoing request's headers.
|
|
// The created span can follow a parent span, if a parent is presented in
|
|
// the request's context.
|
|
func (t Transport) RoundTrip(req *http.Request) (*http.Response, error) {
|
|
span := FromContext(req.Context()).NewRemoteChild(req)
|
|
resp, err := t.base().RoundTrip(req)
|
|
|
|
// TODO(jbd): Is it possible to defer the span.Finish?
|
|
// In cases where RoundTrip panics, we still can finish the span.
|
|
span.Finish(WithResponse(resp))
|
|
return resp, err
|
|
}
|
|
|
|
// CancelRequest cancels an in-flight request by closing its connection.
|
|
func (t Transport) CancelRequest(req *http.Request) {
|
|
type canceler interface {
|
|
CancelRequest(*http.Request)
|
|
}
|
|
if cr, ok := t.base().(canceler); ok {
|
|
cr.CancelRequest(req)
|
|
}
|
|
}
|
|
|
|
func (t Transport) base() http.RoundTripper {
|
|
if t.Base != nil {
|
|
return t.Base
|
|
}
|
|
return http.DefaultTransport
|
|
}
|
|
|
|
// HTTPHandler returns a http.Handler from the given handler
|
|
// that is aware of the incoming request's span.
|
|
// The span can be extracted from the incoming request in handler
|
|
// functions from incoming request's context:
|
|
//
|
|
// span := trace.FromContext(r.Context())
|
|
//
|
|
// The span will be auto finished by the handler.
|
|
func (c *Client) HTTPHandler(h http.Handler) http.Handler {
|
|
if c == nil {
|
|
return h
|
|
}
|
|
return &handler{traceClient: c, handler: h}
|
|
}
|
|
|
|
type handler struct {
|
|
traceClient *Client
|
|
handler http.Handler
|
|
}
|
|
|
|
func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
|
|
traceID, parentSpanID, options, optionsOk, ok := traceInfoFromHeader(r.Header.Get(httpHeader))
|
|
if !ok {
|
|
traceID = nextTraceID()
|
|
}
|
|
t := &trace{
|
|
traceID: traceID,
|
|
client: h.traceClient,
|
|
globalOptions: options,
|
|
localOptions: options,
|
|
}
|
|
span := startNewChildWithRequest(r, t, parentSpanID)
|
|
span.span.Kind = spanKindServer
|
|
span.rootSpan = true
|
|
configureSpanFromPolicy(span, h.traceClient.policy, ok)
|
|
defer span.Finish()
|
|
|
|
r = r.WithContext(NewContext(r.Context(), span))
|
|
if ok && !optionsOk {
|
|
// Inject the trace context back to the response with the sampling options.
|
|
// TODO(jbd): Remove when there is a better way to report the client's sampling.
|
|
w.Header().Set(httpHeader, spanHeader(traceID, parentSpanID, span.trace.localOptions))
|
|
}
|
|
h.handler.ServeHTTP(w, r)
|
|
}
|