// When wait returns, either the new transport is up or ClientConn is
// closing. Used to avoid working on a dying transport. It updates and
// returns the transport and its version when there is no error.
func (cc *ClientConn) wait(ctx context.Context, ts int) (transport.ClientTransport, int, error) {
for {
cc.mu.Lock()
switch {
case cc.closing:
cc.mu.Unlock()
return nil, 0, ErrClientConnClosing
case ts < cc.transportSeq:
// Worked on a dying transport. Try the new one immediately.
defer cc.mu.Unlock()
return cc.transport, cc.transportSeq, nil
default:
ready := cc.ready
if ready == nil {
ready = make(chan struct{})
cc.ready = ready
}
cc.mu.Unlock()
select {
case <-ctx.Done():
return nil, 0, transport.ContextErr(ctx.Err())
// Wait until the new transport is ready or failed.
case <-ready:
}
}
}
}
func (l *lessor) keepAliveCtxCloser(id lease.LeaseID, ctx context.Context, donec <-chan struct{}) {
select {
case <-donec:
return
case <-l.donec:
return
case <-ctx.Done():
}
l.mu.Lock()
defer l.mu.Unlock()
ka, ok := l.keepAlives[id]
if !ok {
return
}
// close channel and remove context if still associated with keep alive
for i, c := range ka.ctxs {
if c == ctx {
close(ka.chs[i])
ka.ctxs = append(ka.ctxs[:i], ka.ctxs[i+1:]...)
ka.chs = append(ka.chs[:i], ka.chs[i+1:]...)
break
}
}
// remove if no one more listeners
if len(ka.chs) == 0 {
delete(l.keepAlives, id)
}
}
// Watch posts a watch request to run() and waits for a new watcher channel
func (w *watcher) Watch(ctx context.Context, key string, opts ...OpOption) WatchChan {
ow := opWatch(key, opts...)
wr := ow.toWatchRequest()
wr.ctx = ctx
retc := make(chan chan WatchResponse, 1)
wr.retc = retc
ok := false
// submit request
select {
case w.reqc <- wr:
ok = true
case <-wr.ctx.Done():
case <-w.donec:
}
// receive channel
if ok {
select {
case ret := <-retc:
return ret
case <-ctx.Done():
case <-w.donec:
}
}
// couldn't create channel; return closed channel
ch := make(chan WatchResponse)
close(ch)
return ch
}
// WaitForStateChange blocks until the state changes to something other than the sourceState.
func (cc *Conn) WaitForStateChange(ctx context.Context, sourceState ConnectivityState) (ConnectivityState, error) {
cc.mu.Lock()
defer cc.mu.Unlock()
if sourceState != cc.state {
return cc.state, nil
}
done := make(chan struct{})
var err error
go func() {
select {
case <-ctx.Done():
cc.mu.Lock()
err = ctx.Err()
cc.stateCV.Broadcast()
cc.mu.Unlock()
case <-done:
}
}()
defer close(done)
for sourceState == cc.state {
cc.stateCV.Wait()
if err != nil {
return cc.state, err
}
}
return cc.state, nil
}
// Do interprets r and performs an operation on s.store according to r.Method
// and other fields. If r.Method is "POST", "PUT", "DELETE", or a "GET" with
// Quorum == true, r will be sent through consensus before performing its
// respective operation. Do will block until an action is performed or there is
// an error.
func (s *EtcdServer) Do(ctx context.Context, r pb.Request) (Response, error) {
r.ID = s.reqIDGen.Next()
if r.Method == "GET" && r.Quorum {
r.Method = "QGET"
}
switch r.Method {
case "POST", "PUT", "DELETE", "QGET":
var raftReq pb.InternalRaftRequest
raftReq.V2 = &r
data, err := raftReq.Marshal()
if err != nil {
return Response{}, err
}
ch := s.w.Register(r.ID)
// TODO: benchmark the cost of time.Now()
// might be sampling?
start := time.Now()
s.r.Propose(ctx, data)
proposePending.Inc()
defer proposePending.Dec()
select {
case x := <-ch:
proposeDurations.Observe(float64(time.Since(start).Nanoseconds() / int64(time.Millisecond)))
resp := x.(Response)
return resp, resp.err
case <-ctx.Done():
proposeFailed.Inc()
s.w.Trigger(r.ID, nil) // GC wait
return Response{}, parseCtxErr(ctx.Err())
case <-s.done:
return Response{}, ErrStopped
}
case "GET":
switch {
case r.Wait:
wc, err := s.store.Watch(r.Path, r.Recursive, r.Stream, r.Since)
if err != nil {
return Response{}, err
}
return Response{Watcher: wc}, nil
default:
ev, err := s.store.Get(r.Path, r.Recursive, r.Sorted)
if err != nil {
return Response{}, err
}
return Response{Event: ev}, nil
}
case "HEAD":
ev, err := s.store.Get(r.Path, r.Recursive, r.Sorted)
if err != nil {
return Response{}, err
}
return Response{Event: ev}, nil
default:
return Response{}, ErrUnknownMethod
}
}
func (s *EtcdServer) processInternalRaftRequest(ctx context.Context, r pb.InternalRaftRequest) (*applyResult, error) {
r.ID = s.reqIDGen.Next()
data, err := r.Marshal()
if err != nil {
return nil, err
}
if len(data) > maxRequestBytes {
return nil, ErrRequestTooLarge
}
ch := s.w.Register(r.ID)
s.r.Propose(ctx, data)
select {
case x := <-ch:
return x.(*applyResult), nil
case <-ctx.Done():
s.w.Trigger(r.ID, nil) // GC wait
return nil, ctx.Err()
case <-s.done:
return nil, ErrStopped
}
}
// Wait blocks until i) the new transport is up or ii) ctx is done or iii) cc is closed.
func (cc *Conn) Wait(ctx context.Context) (transport.ClientTransport, error) {
for {
cc.mu.Lock()
switch {
case cc.state == Shutdown:
cc.mu.Unlock()
return nil, ErrClientConnClosing
case cc.state == Ready:
ct := cc.transport
cc.mu.Unlock()
return ct, nil
default:
ready := cc.ready
if ready == nil {
ready = make(chan struct{})
cc.ready = ready
}
cc.mu.Unlock()
select {
case <-ctx.Done():
return nil, transport.ContextErr(ctx.Err())
// Wait until the new transport is ready or failed.
case <-ready:
}
}
}
}
func (c *simpleHTTPClient) Do(ctx context.Context, act httpAction) (*http.Response, []byte, error) {
req := act.HTTPRequest(c.endpoint)
if err := printcURL(req); err != nil {
return nil, nil, err
}
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():
// cancel and wait for request to actually exit before continuing
c.transport.CancelRequest(req)
rtresp := <-rtchan
resp = rtresp.resp
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 nil, nil, err
}
var body []byte
done := make(chan struct{})
go func() {
body, err = ioutil.ReadAll(resp.Body)
done <- struct{}{}
}()
select {
case <-ctx.Done():
err = resp.Body.Close()
<-done
if err == nil {
err = ctx.Err()
}
case <-done:
}
return resp, body, err
}
// wait blocks until it can receive from ctx.Done, closing, or proceed.
// If it receives from ctx.Done, it returns 0, the StreamError for ctx.Err.
// If it receives from closing, it returns 0, ErrConnClosing.
// If it receives from proceed, it returns the received integer, nil.
func wait(ctx context.Context, closing <-chan struct{}, proceed <-chan int) (int, error) {
select {
case <-ctx.Done():
return 0, ContextErr(ctx.Err())
case <-closing:
return 0, ErrConnClosing
case i := <-proceed:
return i, nil
}
}
// Do sends an HTTP request with the provided http.Client and returns an HTTP response.
// If the client is nil, http.DefaultClient is used.
// If the context is canceled or times out, ctx.Err() will be returned.
func Do(ctx context.Context, client *http.Client, req *http.Request) (*http.Response, error) {
if client == nil {
client = http.DefaultClient
}
// Request cancelation changed in Go 1.5, see cancelreq.go and cancelreq_go14.go.
cancel := canceler(client, req)
type responseAndError struct {
resp *http.Response
err error
}
result := make(chan responseAndError, 1)
go func() {
resp, err := client.Do(req)
testHookDoReturned()
result <- responseAndError{resp, err}
}()
var resp *http.Response
select {
case <-ctx.Done():
testHookContextDoneBeforeHeaders()
cancel()
// Clean up after the goroutine calling client.Do:
go func() {
if r := <-result; r.resp != nil {
testHookDidBodyClose()
r.resp.Body.Close()
}
}()
return nil, ctx.Err()
case r := <-result:
var err error
resp, err = r.resp, r.err
if err != nil {
return resp, err
}
}
c := make(chan struct{})
go func() {
select {
case <-ctx.Done():
cancel()
case <-c:
// The response's Body is closed.
}
}()
resp.Body = ¬ifyingReader{resp.Body, c}
return resp, nil
}
// Do interprets r and performs an operation on s.store according to r.Method
// and other fields. If r.Method is "POST", "PUT", "DELETE", or a "GET" with
// Quorum == true, r will be sent through consensus before performing its
// respective operation. Do will block until an action is performed or there is
// an error.
func (s *EtcdServer) Do(ctx context.Context, r pb.Request) (Response, error) {
if r.ID == 0 {
log.Panicf("request ID should never be 0")
}
if r.Method == "GET" && r.Quorum {
r.Method = "QGET"
}
switch r.Method {
case "POST", "PUT", "DELETE", "QGET":
data, err := r.Marshal()
if err != nil {
return Response{}, err
}
ch := s.w.Register(r.ID)
s.node.Propose(ctx, data)
select {
case x := <-ch:
resp := x.(Response)
return resp, resp.err
case <-ctx.Done():
s.w.Trigger(r.ID, nil) // GC wait
return Response{}, parseCtxErr(ctx.Err())
case <-s.done:
return Response{}, ErrStopped
}
case "GET":
switch {
case r.Wait:
wc, err := s.store.Watch(r.Path, r.Recursive, r.Stream, r.Since)
if err != nil {
return Response{}, err
}
return Response{Watcher: wc}, nil
default:
ev, err := s.store.Get(r.Path, r.Recursive, r.Sorted)
if err != nil {
return Response{}, err
}
return Response{Event: ev}, nil
}
case "HEAD":
ev, err := s.store.Get(r.Path, r.Recursive, r.Sorted)
if err != nil {
return Response{}, err
}
return Response{Event: ev}, nil
default:
return Response{}, ErrUnknownMethod
}
}
func (mn *multiNode) step(ctx context.Context, m multiMessage) error {
ch := mn.recvc
if m.msg.Type == pb.MsgProp {
ch = mn.propc
}
select {
case ch <- m:
return nil
case <-ctx.Done():
return ctx.Err()
case <-mn.done:
return ErrStopped
}
}
func (c *httpClusterClient) AutoSync(ctx context.Context, interval time.Duration) error {
ticker := time.NewTicker(interval)
defer ticker.Stop()
for {
err := c.Sync(ctx)
if err != nil {
return err
}
select {
case <-ctx.Done():
return ctx.Err()
case <-ticker.C:
}
}
}
// Step advances the state machine using msgs. The ctx.Err() will be returned,
// if any.
func (n *node) step(ctx context.Context, m pb.Message) error {
ch := n.recvc
if m.Type == pb.MsgProp {
ch = n.propc
}
select {
case ch <- m:
return nil
case <-ctx.Done():
return ctx.Err()
case <-n.done:
return ErrStopped
}
}
// Lock locks the mutex with a cancellable context. If the context is cancelled
// while trying to acquire the lock, the mutex tries to clean its stale lock entry.
func (m *Mutex) Lock(ctx context.Context) error {
s, err := NewSession(m.client)
if err != nil {
return err
}
// put self in lock waiters via myKey; oldest waiter holds lock
m.myKey, m.myRev, err = NewUniqueKey(ctx, m.client, m.pfx, v3.WithLease(s.Lease()))
// wait for deletion revisions prior to myKey
err = waitDeletes(ctx, m.client, m.pfx, v3.WithPrefix(), v3.WithRev(m.myRev-1))
// release lock key if cancelled
select {
case <-ctx.Done():
m.Unlock()
default:
}
return err
}
// Description:
// A helper routine to renew the TTL of o given key. This routine starts a
// timer and at every tick attempts to renew the TTL of the given key.
//
// Parameters:
// @ctx - A context object used to stop the renewal operation.
// @key - The key for which the TTL needs to be renewed.
// @val - The value associated with the key.
// @ttl - TTL value in seconds.
// @refresh - Interval, in seconds, at which the TTL will be renewed.
//
// Return value:
// @out - A channel on which errors will be reported back to the caller.
func (ec *EtcdConnector) RenewTTL(ctx context.Context, key, val string, ttl, refresh time.Duration) <-chan error {
out := make(chan error)
// Start a ticker to trigger at every @refresh seconds.
ticker := time.NewTicker(refresh)
// Launch a go routine to handle the periodic TTL renewal of @key.
go func() {
opts := &client.SetOptions{PrevExist: client.PrevExist, TTL: ttl}
// Wait for activity either on the ticker channel or @ctx's channel.
for {
select {
case <-ticker.C:
// Update the TTL of @key.
_, err := ec.Set(ctx, key, val, opts)
if err != nil {
// In case of an error, put out the error info on the
// outward channel and return.
out <- err
close(out)
return
}
case <-ctx.Done():
// If we are here then it's indication by the caller to stop the
// renewal operation. So kill the ticker, delete @key, close the
// outward channel and return.
ticker.Stop()
// Deletion is best effort here and also an optimization. We end
// up here only when the program is being shutdown or when a
// catastrophic failure occurs. If we succeed in deleting @key
// then entities watching @key will get notified quickly or else
// they'll have to wait for the TTL to expire. But if we get here
// because of catastrophic failure then it's a best effort as the
// delete can also fail.
ec.Delete(context.Background(), key, &client.DeleteOptions{})
close(out)
return
}
}
}()
return out
}
func handleKeyWatch(ctx context.Context, w http.ResponseWriter, wa store.Watcher, stream bool, rt etcdserver.RaftTimer) {
defer wa.Remove()
ech := wa.EventChan()
var nch <-chan bool
if x, ok := w.(http.CloseNotifier); ok {
nch = x.CloseNotify()
}
w.Header().Set("Content-Type", "application/json")
w.Header().Set("X-Etcd-Index", fmt.Sprint(wa.StartIndex()))
w.Header().Set("X-Raft-Index", fmt.Sprint(rt.Index()))
w.Header().Set("X-Raft-Term", fmt.Sprint(rt.Term()))
w.WriteHeader(http.StatusOK)
// Ensure headers are flushed early, in case of long polling
w.(http.Flusher).Flush()
for {
select {
case <-nch:
// Client closed connection. Nothing to do.
return
case <-ctx.Done():
// Timed out. net/http will close the connection for us, so nothing to do.
return
case ev, ok := <-ech:
if !ok {
// If the channel is closed this may be an indication of
// that notifications are much more than we are able to
// send to the client in time. Then we simply end streaming.
return
}
ev = trimEventPrefix(ev, etcdserver.StoreKeysPrefix)
if err := json.NewEncoder(w).Encode(ev); err != nil {
// Should never be reached
plog.Warningf("error writing event (%v)", err)
return
}
if !stream {
return
}
w.(http.Flusher).Flush()
}
}
}
// watch posts a watch request to run() and waits for a new watcher channel
func (w *watcher) watch(ctx context.Context, key, prefix string, rev int64) <-chan WatchResponse {
retc := make(chan chan WatchResponse, 1)
wr := &watchRequest{ctx: ctx, key: key, prefix: prefix, rev: rev, retc: retc}
// submit request
select {
case w.reqc <- wr:
case <-wr.ctx.Done():
return nil
case <-w.donec:
return nil
}
// receive channel
select {
case ret := <-retc:
return ret
case <-ctx.Done():
return nil
case <-w.donec:
return nil
}
}
// Step advances the state machine using msgs. The ctx.Err() will be returned,
// if any.
func (n *node) step(ctx context.Context, m pb.Message) error {
ch := n.recvc
if m.Type == pb.MsgProp {
ch = n.propc
}
select {
case ch <- m:
if m.Type == pb.MsgProp {
//NOTE: this case is accessed before quorum check
//plog.Infof("message is in channel")
}
return nil
case <-ctx.Done():
//plog.Infof("context is done, should not happen")
return ctx.Err()
case <-n.done:
//plog.Infof("node stopped")
return ErrStopped
}
}
// Lock locks the mutex with a cancellable context. If the context is cancelled
// while trying to acquire the lock, the mutex tries to clean its stale lock entry.
func (m *Mutex) Lock(ctx context.Context) error {
s, err := NewSession(m.client)
if err != nil {
return err
}
// put self in lock waiters via myKey; oldest waiter holds lock
m.myKey, m.myRev, err = NewUniqueKey(ctx, m.kv, m.pfx, v3.WithLease(s.Lease()))
// wait for lock to become available
for err == nil {
// find oldest element in waiters via revision of insertion
var resp *v3.GetResponse
resp, err = m.kv.Get(ctx, m.pfx, v3.WithFirstRev()...)
if err != nil {
break
}
if m.myRev == resp.Kvs[0].CreateRevision {
// myKey is oldest in waiters; myKey holds the lock now
return nil
}
// otherwise myKey isn't lowest, so there must be a pfx prior to myKey
opts := append(v3.WithLastRev(), v3.WithRev(m.myRev-1))
resp, err = m.kv.Get(ctx, m.pfx, opts...)
if err != nil {
break
}
lastKey := string(resp.Kvs[0].Key)
// wait for release on prior pfx
err = waitUpdate(ctx, m.client, lastKey, v3.WithRev(m.myRev))
// try again in case lastKey left the wait list before acquiring the lock;
// myKey can only hold the lock if it's the oldest in the list
}
// release lock key if cancelled
select {
case <-ctx.Done():
m.Unlock()
default:
}
return err
}
// configure sends a configuration change through consensus and
// then waits for it to be applied to the server. It
// will block until the change is performed or there is an error.
func (s *EtcdServer) configure(ctx context.Context, cc raftpb.ConfChange) error {
ch := s.w.Register(cc.ID)
if err := s.node.ProposeConfChange(ctx, cc); err != nil {
s.w.Trigger(cc.ID, nil)
return err
}
select {
case x := <-ch:
if err, ok := x.(error); ok {
return err
}
if x != nil {
log.Panicf("return type should always be error")
}
return nil
case <-ctx.Done():
s.w.Trigger(cc.ID, nil) // GC wait
return parseCtxErr(ctx.Err())
case <-s.done:
return ErrStopped
}
}
func (s *EtcdServer) V3DemoDo(ctx context.Context, r pb.InternalRaftRequest) (proto.Message, error) {
r.ID = s.reqIDGen.Next()
data, err := r.Marshal()
if err != nil {
return &pb.EmptyResponse{}, err
}
ch := s.w.Register(r.ID)
s.r.Propose(ctx, data)
select {
case x := <-ch:
resp := x.(proto.Message)
return resp, nil
case <-ctx.Done():
s.w.Trigger(r.ID, nil) // GC wait
return &pb.EmptyResponse{}, ctx.Err()
case <-s.done:
return &pb.EmptyResponse{}, ErrStopped
}
}
func (c *httpClient) Do(ctx context.Context, act HTTPAction) (*http.Response, []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 nil, nil, err
}
body, err := ioutil.ReadAll(resp.Body)
return resp, body, err
}
// Watch posts a watch request to run() and waits for a new watcher channel
func (w *watcher) Watch(ctx context.Context, key string, opts ...OpOption) WatchChan {
ow := opWatch(key, opts...)
retc := make(chan chan WatchResponse, 1)
wr := &watchRequest{
ctx: ctx,
key: string(ow.key),
end: string(ow.end),
rev: ow.rev,
progressNotify: ow.progressNotify,
retc: retc,
}
ok := false
// submit request
select {
case w.reqc <- wr:
ok = true
case <-wr.ctx.Done():
case <-w.donec:
}
// receive channel
if ok {
select {
case ret := <-retc:
return ret
case <-ctx.Done():
case <-w.donec:
}
}
// couldn't create channel; return closed channel
ch := make(chan WatchResponse)
close(ch)
return ch
}
// Campaign puts a value as eligible for the election. It blocks until
// it is elected, an error occurs, or the context is cancelled.
func (e *Election) Campaign(ctx context.Context, val string) error {
s, serr := NewSession(e.client)
if serr != nil {
return serr
}
k, rev, err := NewUniqueKV(ctx, e.client, e.keyPrefix, val, v3.WithLease(s.Lease()))
if err == nil {
err = waitDeletes(ctx, e.client, e.keyPrefix, v3.WithPrefix(), v3.WithRev(rev-1))
}
if err != nil {
// clean up in case of context cancel
select {
case <-ctx.Done():
e.client.Delete(e.client.Ctx(), k)
default:
}
return err
}
e.leaderKey, e.leaderRev, e.leaderSession = k, rev, s
return nil
}
func (n *nodeProposalBlockerRecorder) Propose(ctx context.Context, data []byte) error {
<-ctx.Done()
n.Record(testutil.Action{Name: "Propose blocked"})
return nil
}
func (c *simpleHTTPClient) Do(ctx context.Context, act httpAction) (*http.Response, []byte, error) {
req := act.HTTPRequest(c.endpoint)
if err := printcURL(req); err != nil {
return nil, nil, err
}
hctx, hcancel := context.WithCancel(ctx)
if c.headerTimeout > 0 {
hctx, hcancel = context.WithTimeout(ctx, c.headerTimeout)
}
defer hcancel()
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 <-hctx.Done():
// cancel and wait for request to actually exit before continuing
c.transport.CancelRequest(req)
rtresp := <-rtchan
resp = rtresp.resp
switch {
case ctx.Err() != nil:
err = ctx.Err()
case hctx.Err() != nil:
err = fmt.Errorf("client: endpoint %s exceeded header timeout", c.endpoint.String())
default:
panic("failed to get error from context")
}
}
// 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 nil, nil, err
}
var body []byte
done := make(chan struct{})
go func() {
body, err = ioutil.ReadAll(resp.Body)
done <- struct{}{}
}()
select {
case <-ctx.Done():
resp.Body.Close()
<-done
return nil, nil, ctx.Err()
case <-done:
}
return resp, body, err
}
func (c *simpleHTTPClient) Do(ctx context.Context, act httpAction) (*http.Response, []byte, error) {
req := act.HTTPRequest(c.endpoint)
if err := printcURL(req); err != nil {
return nil, nil, err
}
isWait := false
if req != nil && req.URL != nil {
ws := req.URL.Query().Get("wait")
if len(ws) != 0 {
var err error
isWait, err = strconv.ParseBool(ws)
if err != nil {
return nil, nil, fmt.Errorf("wrong wait value %s (%v for %+v)", ws, err, req)
}
}
}
var hctx context.Context
var hcancel context.CancelFunc
if !isWait && c.headerTimeout > 0 {
hctx, hcancel = context.WithTimeout(ctx, c.headerTimeout)
} else {
hctx, hcancel = context.WithCancel(ctx)
}
defer hcancel()
reqcancel := requestCanceler(c.transport, req)
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 <-hctx.Done():
// cancel and wait for request to actually exit before continuing
reqcancel()
rtresp := <-rtchan
resp = rtresp.resp
switch {
case ctx.Err() != nil:
err = ctx.Err()
case hctx.Err() != nil:
err = fmt.Errorf("client: endpoint %s exceeded header timeout", c.endpoint.String())
default:
panic("failed to get error from context")
}
}
// 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 nil, nil, err
}
var body []byte
done := make(chan struct{})
go func() {
body, err = ioutil.ReadAll(resp.Body)
done <- struct{}{}
}()
select {
case <-ctx.Done():
resp.Body.Close()
<-done
return nil, nil, ctx.Err()
case <-done:
}
return resp, body, err
}