157 lines
3.4 KiB
Go
157 lines
3.4 KiB
Go
/*
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Copyright 2014 CoreOS, Inc.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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*/
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package client
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import (
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"io/ioutil"
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"net/http"
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"net/url"
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"time"
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"github.com/coreos/etcd/Godeps/_workspace/src/code.google.com/p/go.net/context"
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)
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var (
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ErrTimeout = context.DeadlineExceeded
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DefaultRequestTimeout = 5 * time.Second
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)
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type SyncableHTTPClient interface {
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HTTPClient
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Sync(context.Context) error
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}
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type HTTPClient interface {
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Do(context.Context, HTTPAction) (*http.Response, []byte, error)
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}
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type HTTPAction interface {
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HTTPRequest(url.URL) *http.Request
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}
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// CancelableTransport mimics http.Transport to provide an interface which can be
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// substituted for testing (since the RoundTripper interface alone does not
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// require the CancelRequest method)
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type CancelableTransport interface {
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http.RoundTripper
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CancelRequest(req *http.Request)
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}
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func NewHTTPClient(tr CancelableTransport, eps []string) (SyncableHTTPClient, error) {
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return newHTTPClusterClient(tr, eps)
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}
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func newHTTPClusterClient(tr CancelableTransport, eps []string) (*httpClusterClient, error) {
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c := httpClusterClient{
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transport: tr,
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endpoints: make([]HTTPClient, len(eps)),
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}
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for i, ep := range eps {
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u, err := url.Parse(ep)
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if err != nil {
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return nil, err
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}
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c.endpoints[i] = &httpClient{
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transport: tr,
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endpoint: *u,
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}
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}
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return &c, nil
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}
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type httpClusterClient struct {
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transport CancelableTransport
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endpoints []HTTPClient
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}
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func (c *httpClusterClient) Do(ctx context.Context, act HTTPAction) (*http.Response, []byte, error) {
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//TODO(bcwaldon): introduce retry logic so all endpoints are attempted
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return c.endpoints[0].Do(ctx, act)
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}
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func (c *httpClusterClient) Sync(ctx context.Context) error {
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mAPI := NewMembersAPI(c)
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ms, err := mAPI.List(ctx)
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if err != nil {
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return err
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}
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eps := make([]string, 0)
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for _, m := range ms {
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eps = append(eps, m.ClientURLs...)
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}
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nc, err := newHTTPClusterClient(c.transport, eps)
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if err != nil {
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return err
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}
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*c = *nc
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return nil
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}
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type roundTripResponse struct {
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resp *http.Response
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err error
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}
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type httpClient struct {
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transport CancelableTransport
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endpoint url.URL
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}
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func (c *httpClient) Do(ctx context.Context, act HTTPAction) (*http.Response, []byte, error) {
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req := act.HTTPRequest(c.endpoint)
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rtchan := make(chan roundTripResponse, 1)
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go func() {
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resp, err := c.transport.RoundTrip(req)
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rtchan <- roundTripResponse{resp: resp, err: err}
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close(rtchan)
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}()
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var resp *http.Response
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var err error
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select {
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case rtresp := <-rtchan:
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resp, err = rtresp.resp, rtresp.err
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case <-ctx.Done():
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c.transport.CancelRequest(req)
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// wait for request to actually exit before continuing
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<-rtchan
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err = ctx.Err()
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}
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// always check for resp nil-ness to deal with possible
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// race conditions between channels above
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defer func() {
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if resp != nil {
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resp.Body.Close()
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}
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}()
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if err != nil {
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return nil, nil, err
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}
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body, err := ioutil.ReadAll(resp.Body)
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return resp, body, err
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}
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