Golang httputil.RequestCanceler函数代码示例

// TimeToLiveHTTP retrieves lease information of the given lease ID.
func TimeToLiveHTTP(ctx context.Context, id lease.LeaseID, keys bool, url string, rt http.RoundTripper) (*leasepb.LeaseInternalResponse, error) {
	// will post lreq protobuf to leader
	lreq, err := (&leasepb.LeaseInternalRequest{&pb.LeaseTimeToLiveRequest{ID: int64(id), Keys: keys}}).Marshal()
	if err != nil {
		return nil, err
	}

	req, err := http.NewRequest("POST", url, bytes.NewReader(lreq))
	if err != nil {
		return nil, err
	}
	req.Header.Set("Content-Type", "application/protobuf")

	cancel := httputil.RequestCanceler(req)

	cc := &http.Client{Transport: rt}
	var b []byte
	errc := make(chan error)
	go func() {
		// TODO detect if leader failed and retry?
		resp, err := cc.Do(req)
		if err != nil {
			errc <- err
			return
		}
		b, err = ioutil.ReadAll(resp.Body)
		resp.Body.Close()
		if err != nil {
			errc <- err
			return
		}
		if resp.StatusCode == http.StatusNotFound {
			errc <- lease.ErrLeaseNotFound
			return
		}
		if resp.StatusCode != http.StatusOK {
			errc <- fmt.Errorf("lease: unknown error(%s)", string(b))
			return
		}
		errc <- nil
	}()
	select {
	case derr := <-errc:
		if derr != nil {
			return nil, derr
		}
	case <-ctx.Done():
		cancel()
		return nil, ctx.Err()
	}

	lresp := &leasepb.LeaseInternalResponse{}
	if err := lresp.Unmarshal(b); err != nil {
		return nil, fmt.Errorf(`lease: %v. data = "%s"`, err, string(b))
	}
	if lresp.LeaseTimeToLiveResponse.ID != int64(id) {
		return nil, fmt.Errorf("lease: renew id mismatch")
	}
	return lresp, nil
}

// post POSTs a data payload to a url. Returns nil if the POST succeeds,
// error on any failure.
func (p *pipeline) post(data []byte) (err error) {
	u := p.picker.pick()
	req := createPostRequest(u, RaftPrefix, bytes.NewBuffer(data), "application/protobuf", p.from, p.cid)

	var stopped bool
	defer func() {
		if stopped {
			// rewrite to errStopped so the caller goroutine can stop itself
			err = errStopped
		}
	}()
	done := make(chan struct{}, 1)
	cancel := httputil.RequestCanceler(p.tr, req)
	go func() {
		select {
		case <-done:
		case <-p.stopc:
			waitSchedule()
			stopped = true
			cancel()
		}
	}()

	resp, err := p.tr.RoundTrip(req)
	done <- struct{}{}
	if err != nil {
		p.picker.unreachable(u)
		return err
	}
	b, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		p.picker.unreachable(u)
		return err
	}
	resp.Body.Close()

	err = checkPostResponse(resp, b, req, p.to)
	// errMemberRemoved is a critical error since a removed member should
	// always be stopped. So we use reportCriticalError to report it to errorc.
	if err == errMemberRemoved {
		reportCriticalError(err, p.errorc)
		return nil
	}
	return err
}

// post POSTs a data payload to a url. Returns nil if the POST succeeds,
// error on any failure.
func (p *pipeline) post(data []byte) (err error) {
	u := p.picker.pick()
	req := createPostRequest(u, RaftPrefix, bytes.NewBuffer(data), "application/protobuf", p.tr.URLs, p.tr.ID, p.tr.ClusterID)

	done := make(chan struct{}, 1)
	cancel := httputil.RequestCanceler(req)
	go func() {
		select {
		case <-done:
		case <-p.stopc:
			waitSchedule()
			cancel()
		}
	}()

	resp, err := p.tr.pipelineRt.RoundTrip(req)
	done <- struct{}{}
	if err != nil {
		p.picker.unreachable(u)
		return err
	}
	b, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		p.picker.unreachable(u)
		return err
	}
	resp.Body.Close()

	err = checkPostResponse(resp, b, req, p.peerID)
	if err != nil {
		p.picker.unreachable(u)
		// errMemberRemoved is a critical error since a removed member should
		// always be stopped. So we use reportCriticalError to report it to errorc.
		if err == errMemberRemoved {
			reportCriticalError(err, p.errorc)
		}
		return err
	}

	return nil
}

// post posts the given request.
// It returns nil when request is sent out and processed successfully.
func (s *snapshotSender) post(req *http.Request) (err error) {
	cancel := httputil.RequestCanceler(s.tr, req)

	type responseAndError struct {
		resp *http.Response
		body []byte
		err  error
	}
	result := make(chan responseAndError, 1)

	go func() {
		// TODO: cancel the request if it has waited for a long time(~5s) after
		// it has write out the full request body, which helps to avoid receiver
		// dies when sender is waiting for response
		// TODO: the snapshot could be large and eat up all resources when writing
		// it out. Send it block by block and rest some time between to give the
		// time for main loop to run.
		resp, err := s.tr.RoundTrip(req)
		if err != nil {
			result <- responseAndError{resp, nil, err}
			return
		}
		body, err := ioutil.ReadAll(resp.Body)
		resp.Body.Close()
		result <- responseAndError{resp, body, err}
	}()

	select {
	case <-s.stopc:
		cancel()
		return errStopped
	case r := <-result:
		if r.err != nil {
			return r.err
		}
		return checkPostResponse(r.resp, r.body, req, s.to)
	}
}

// post posts the given request.
// It returns nil when request is sent out and processed successfully.
func (s *snapshotSender) post(req *http.Request) (err error) {
	cancel := httputil.RequestCanceler(req)

	type responseAndError struct {
		resp *http.Response
		body []byte
		err  error
	}
	result := make(chan responseAndError, 1)

	go func() {
		resp, err := s.tr.pipelineRt.RoundTrip(req)
		if err != nil {
			result <- responseAndError{resp, nil, err}
			return
		}

		// close the response body when timeouts.
		// prevents from reading the body forever when the other side dies right after
		// successfully receives the request body.
		time.AfterFunc(snapResponseReadTimeout, func() { httputil.GracefulClose(resp) })
		body, err := ioutil.ReadAll(resp.Body)
		result <- responseAndError{resp, body, err}
	}()

	select {
	case <-s.stopc:
		cancel()
		return errStopped
	case r := <-result:
		if r.err != nil {
			return r.err
		}
		return checkPostResponse(r.resp, r.body, req, s.to)
	}
}

func (cr *streamReader) dial(t streamType) (io.ReadCloser, error) {
	u := cr.picker.pick()
	uu := u
	uu.Path = path.Join(t.endpoint(), cr.local.String())

	req, err := http.NewRequest("GET", uu.String(), nil)
	if err != nil {
		cr.picker.unreachable(u)
		return nil, fmt.Errorf("failed to make http request to %s (%v)", u, err)
	}
	req.Header.Set("X-Server-From", cr.local.String())
	req.Header.Set("X-Server-Version", version.Version)
	req.Header.Set("X-Min-Cluster-Version", version.MinClusterVersion)
	req.Header.Set("X-Etcd-Cluster-ID", cr.cid.String())
	req.Header.Set("X-Raft-To", cr.remote.String())

	cr.mu.Lock()
	select {
	case <-cr.stopc:
		cr.mu.Unlock()
		return nil, fmt.Errorf("stream reader is stopped")
	default:
	}
	cr.cancel = httputil.RequestCanceler(cr.tr, req)
	cr.mu.Unlock()

	resp, err := cr.tr.RoundTrip(req)
	if err != nil {
		cr.picker.unreachable(u)
		return nil, err
	}

	rv := serverVersion(resp.Header)
	lv := semver.Must(semver.NewVersion(version.Version))
	if compareMajorMinorVersion(rv, lv) == -1 && !checkStreamSupport(rv, t) {
		resp.Body.Close()
		return nil, errUnsupportedStreamType
	}

	switch resp.StatusCode {
	case http.StatusGone:
		resp.Body.Close()
		err := fmt.Errorf("the member has been permanently removed from the cluster")
		select {
		case cr.errorc <- err:
		default:
		}
		return nil, err
	case http.StatusOK:
		return resp.Body, nil
	case http.StatusNotFound:
		resp.Body.Close()
		return nil, fmt.Errorf("remote member %s could not recognize local member", cr.remote)
	case http.StatusPreconditionFailed:
		b, err := ioutil.ReadAll(resp.Body)
		if err != nil {
			cr.picker.unreachable(u)
			return nil, err
		}
		resp.Body.Close()

		switch strings.TrimSuffix(string(b), "\n") {
		case errIncompatibleVersion.Error():
			plog.Errorf("request sent was ignored by peer %s (server version incompatible)", cr.remote)
			return nil, errIncompatibleVersion
		case errClusterIDMismatch.Error():
			plog.Errorf("request sent was ignored (cluster ID mismatch: remote[%s]=%s, local=%s)",
				cr.remote, resp.Header.Get("X-Etcd-Cluster-ID"), cr.cid)
			return nil, errClusterIDMismatch
		default:
			return nil, fmt.Errorf("unhandled error %q when precondition failed", string(b))
		}
	default:
		resp.Body.Close()
		return nil, fmt.Errorf("unhandled http status %d", resp.StatusCode)
	}
}

// post POSTs a data payload to a url. Returns nil if the POST succeeds,
// error on any failure.
func (p *pipeline) post(data []byte) (err error) {
	u := p.picker.pick()
	uu := u
	uu.Path = RaftPrefix
	req, err := http.NewRequest("POST", uu.String(), bytes.NewBuffer(data))
	if err != nil {
		p.picker.unreachable(u)
		return err
	}
	req.Header.Set("Content-Type", "application/protobuf")
	req.Header.Set("X-Server-From", p.from.String())
	req.Header.Set("X-Server-Version", version.Version)
	req.Header.Set("X-Min-Cluster-Version", version.MinClusterVersion)
	req.Header.Set("X-Etcd-Cluster-ID", p.cid.String())

	var stopped bool
	defer func() {
		if stopped {
			// rewrite to errStopped so the caller goroutine can stop itself
			err = errStopped
		}
	}()
	done := make(chan struct{}, 1)
	cancel := httputil.RequestCanceler(p.tr, req)
	go func() {
		select {
		case <-done:
		case <-p.stopc:
			waitSchedule()
			stopped = true
			cancel()
		}
	}()

	resp, err := p.tr.RoundTrip(req)
	done <- struct{}{}
	if err != nil {
		p.picker.unreachable(u)
		return err
	}
	b, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		p.picker.unreachable(u)
		return err
	}
	resp.Body.Close()

	switch resp.StatusCode {
	case http.StatusPreconditionFailed:
		switch strings.TrimSuffix(string(b), "\n") {
		case errIncompatibleVersion.Error():
			plog.Errorf("request sent was ignored by peer %s (server version incompatible)", p.to)
			return errIncompatibleVersion
		case errClusterIDMismatch.Error():
			plog.Errorf("request sent was ignored (cluster ID mismatch: remote[%s]=%s, local=%s)",
				p.to, resp.Header.Get("X-Etcd-Cluster-ID"), p.cid)
			return errClusterIDMismatch
		default:
			return fmt.Errorf("unhandled error %q when precondition failed", string(b))
		}
	case http.StatusForbidden:
		err := fmt.Errorf("the member has been permanently removed from the cluster")
		select {
		case p.errorc <- err:
		default:
		}
		return nil
	case http.StatusNoContent:
		return nil
	default:
		return fmt.Errorf("unexpected http status %s while posting to %q", http.StatusText(resp.StatusCode), req.URL.String())
	}
}

func (p *reverseProxy) ServeHTTP(rw http.ResponseWriter, clientreq *http.Request) {
	proxyreq := new(http.Request)
	*proxyreq = *clientreq
	startTime := time.Now()

	var (
		proxybody []byte
		err       error
	)

	if clientreq.Body != nil {
		proxybody, err = ioutil.ReadAll(clientreq.Body)
		if err != nil {
			msg := fmt.Sprintf("proxy: failed to read request body: %v", err)
			e := httptypes.NewHTTPError(http.StatusInternalServerError, msg)
			if we := e.WriteTo(rw); we != nil {
				plog.Debugf("error writing HTTPError (%v) to %s", we, clientreq.RemoteAddr)
			}
			return
		}
	}

	// deep-copy the headers, as these will be modified below
	proxyreq.Header = make(http.Header)
	copyHeader(proxyreq.Header, clientreq.Header)

	normalizeRequest(proxyreq)
	removeSingleHopHeaders(&proxyreq.Header)
	maybeSetForwardedFor(proxyreq)

	endpoints := p.director.endpoints()
	if len(endpoints) == 0 {
		msg := "proxy: zero endpoints currently available"
		reportRequestDropped(clientreq, zeroEndpoints)

		// TODO: limit the rate of the error logging.
		log.Printf(msg)
		e := httptypes.NewHTTPError(http.StatusServiceUnavailable, msg)
		if we := e.WriteTo(rw); we != nil {
			plog.Debugf("error writing HTTPError (%v) to %s", we, clientreq.RemoteAddr)
		}
		return
	}

	var requestClosed int32
	completeCh := make(chan bool, 1)
	closeNotifier, ok := rw.(http.CloseNotifier)
	cancel := httputil.RequestCanceler(p.transport, proxyreq)
	if ok {
		go func() {
			select {
			case <-closeNotifier.CloseNotify():
				atomic.StoreInt32(&requestClosed, 1)
				log.Printf("proxy: client %v closed request prematurely", clientreq.RemoteAddr)
				cancel()
			case <-completeCh:
			}
		}()

		defer func() {
			completeCh <- true
		}()
	}

	var res *http.Response

	for _, ep := range endpoints {
		if proxybody != nil {
			proxyreq.Body = ioutil.NopCloser(bytes.NewBuffer(proxybody))
		}
		redirectRequest(proxyreq, ep.URL)

		res, err = p.transport.RoundTrip(proxyreq)
		if atomic.LoadInt32(&requestClosed) == 1 {
			return
		}
		if err != nil {
			reportRequestDropped(clientreq, failedSendingRequest)
			log.Printf("proxy: failed to direct request to %s: %v", ep.URL.String(), err)
			ep.Failed()
			continue
		}

		break
	}

	if res == nil {
		// TODO: limit the rate of the error logging.
		msg := fmt.Sprintf("proxy: unable to get response from %d endpoint(s)", len(endpoints))
		reportRequestDropped(clientreq, failedGettingResponse)
		log.Printf(msg)
		e := httptypes.NewHTTPError(http.StatusBadGateway, msg)
		if we := e.WriteTo(rw); we != nil {
			plog.Debugf("error writing HTTPError (%v) to %s", we, clientreq.RemoteAddr)
		}
		return
	}

	defer res.Body.Close()
	reportRequestHandled(clientreq, res, startTime)
//.........这里部分代码省略.........

func (cr *streamReader) dial(t streamType) (io.ReadCloser, error) {
	u := cr.picker.pick()
	uu := u
	uu.Path = path.Join(t.endpoint(), cr.tr.ID.String())

	req, err := http.NewRequest("GET", uu.String(), nil)
	if err != nil {
		cr.picker.unreachable(u)
		return nil, fmt.Errorf("failed to make http request to %v (%v)", u, err)
	}
	req.Header.Set("X-Server-From", cr.tr.ID.String())
	req.Header.Set("X-Server-Version", version.Version)
	req.Header.Set("X-Min-Cluster-Version", version.MinClusterVersion)
	req.Header.Set("X-Etcd-Cluster-ID", cr.tr.ClusterID.String())
	req.Header.Set("X-Raft-To", cr.peerID.String())

	setPeerURLsHeader(req, cr.tr.URLs)

	cr.mu.Lock()
	select {
	case <-cr.stopc:
		cr.mu.Unlock()
		return nil, fmt.Errorf("stream reader is stopped")
	default:
	}
	cr.cancel = httputil.RequestCanceler(req)
	cr.mu.Unlock()

	resp, err := cr.tr.streamRt.RoundTrip(req)
	if err != nil {
		cr.picker.unreachable(u)
		return nil, err
	}

	rv := serverVersion(resp.Header)
	lv := semver.Must(semver.NewVersion(version.Version))
	if compareMajorMinorVersion(rv, lv) == -1 && !checkStreamSupport(rv, t) {
		httputil.GracefulClose(resp)
		cr.picker.unreachable(u)
		return nil, errUnsupportedStreamType
	}

	switch resp.StatusCode {
	case http.StatusGone:
		httputil.GracefulClose(resp)
		cr.picker.unreachable(u)
		reportCriticalError(errMemberRemoved, cr.errorc)
		return nil, errMemberRemoved
	case http.StatusOK:
		return resp.Body, nil
	case http.StatusNotFound:
		httputil.GracefulClose(resp)
		cr.picker.unreachable(u)
		return nil, fmt.Errorf("peer %s failed to find local node %s", cr.peerID, cr.tr.ID)
	case http.StatusPreconditionFailed:
		b, err := ioutil.ReadAll(resp.Body)
		if err != nil {
			cr.picker.unreachable(u)
			return nil, err
		}
		httputil.GracefulClose(resp)
		cr.picker.unreachable(u)

		switch strings.TrimSuffix(string(b), "\n") {
		case errIncompatibleVersion.Error():
			plog.Errorf("request sent was ignored by peer %s (server version incompatible)", cr.peerID)
			return nil, errIncompatibleVersion
		case errClusterIDMismatch.Error():
			plog.Errorf("request sent was ignored (cluster ID mismatch: peer[%s]=%s, local=%s)",
				cr.peerID, resp.Header.Get("X-Etcd-Cluster-ID"), cr.tr.ClusterID)
			return nil, errClusterIDMismatch
		default:
			return nil, fmt.Errorf("unhandled error %q when precondition failed", string(b))
		}
	default:
		httputil.GracefulClose(resp)
		cr.picker.unreachable(u)
		return nil, fmt.Errorf("unhandled http status %d", resp.StatusCode)
	}
}