etcd/client/http.go

100 lines
2.3 KiB
Go

/*
Copyright 2014 CoreOS, Inc.
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 client
import (
"io/ioutil"
"net/http"
"net/url"
"time"
"github.com/coreos/etcd/Godeps/_workspace/src/code.google.com/p/go.net/context"
)
var (
ErrTimeout = context.DeadlineExceeded
DefaultRequestTimeout = 5 * time.Second
)
// transport mimics http.Transport to provide an interface which can be
// substituted for testing (since the RoundTripper interface alone does not
// require the CancelRequest method)
type transport interface {
http.RoundTripper
CancelRequest(req *http.Request)
}
type httpAction interface {
httpRequest(url.URL) *http.Request
}
type roundTripResponse struct {
resp *http.Response
err error
}
type httpClient struct {
transport transport
endpoint url.URL
timeout time.Duration
}
func (c *httpClient) doWithTimeout(act httpAction) (int, []byte, error) {
ctx, cancel := context.WithTimeout(context.Background(), c.timeout)
defer cancel()
return c.do(ctx, act)
}
func (c *httpClient) do(ctx context.Context, act httpAction) (int, []byte, error) {
req := act.httpRequest(c.endpoint)
rtchan := make(chan roundTripResponse, 1)
go func() {
resp, err := c.transport.RoundTrip(req)
rtchan <- roundTripResponse{resp: resp, err: err}
close(rtchan)
}()
var resp *http.Response
var err error
select {
case rtresp := <-rtchan:
resp, err = rtresp.resp, rtresp.err
case <-ctx.Done():
c.transport.CancelRequest(req)
// wait for request to actually exit before continuing
<-rtchan
err = ctx.Err()
}
// always check for resp nil-ness to deal with possible
// race conditions between channels above
defer func() {
if resp != nil {
resp.Body.Close()
}
}()
if err != nil {
return 0, nil, err
}
body, err := ioutil.ReadAll(resp.Body)
return resp.StatusCode, body, err
}