gorush/vendor/google.golang.org/grpc/clientconn.go

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/*
*
* Copyright 2014 gRPC authors.
*
* 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 grpc
import (
"errors"
"fmt"
"net"
"strings"
"sync"
"time"
"golang.org/x/net/context"
"golang.org/x/net/trace"
"google.golang.org/grpc/credentials"
"google.golang.org/grpc/grpclog"
"google.golang.org/grpc/keepalive"
"google.golang.org/grpc/stats"
"google.golang.org/grpc/transport"
)
var (
// ErrClientConnClosing indicates that the operation is illegal because
// the ClientConn is closing.
ErrClientConnClosing = errors.New("grpc: the client connection is closing")
// ErrClientConnTimeout indicates that the ClientConn cannot establish the
// underlying connections within the specified timeout.
// DEPRECATED: Please use context.DeadlineExceeded instead.
ErrClientConnTimeout = errors.New("grpc: timed out when dialing")
// errNoTransportSecurity indicates that there is no transport security
// being set for ClientConn. Users should either set one or explicitly
// call WithInsecure DialOption to disable security.
errNoTransportSecurity = errors.New("grpc: no transport security set (use grpc.WithInsecure() explicitly or set credentials)")
// errTransportCredentialsMissing indicates that users want to transmit security
// information (e.g., oauth2 token) which requires secure connection on an insecure
// connection.
errTransportCredentialsMissing = errors.New("grpc: the credentials require transport level security (use grpc.WithTransportCredentials() to set)")
// errCredentialsConflict indicates that grpc.WithTransportCredentials()
// and grpc.WithInsecure() are both called for a connection.
errCredentialsConflict = errors.New("grpc: transport credentials are set for an insecure connection (grpc.WithTransportCredentials() and grpc.WithInsecure() are both called)")
// errNetworkIO indicates that the connection is down due to some network I/O error.
errNetworkIO = errors.New("grpc: failed with network I/O error")
// errConnDrain indicates that the connection starts to be drained and does not accept any new RPCs.
errConnDrain = errors.New("grpc: the connection is drained")
// errConnClosing indicates that the connection is closing.
errConnClosing = errors.New("grpc: the connection is closing")
// errConnUnavailable indicates that the connection is unavailable.
errConnUnavailable = errors.New("grpc: the connection is unavailable")
// errBalancerClosed indicates that the balancer is closed.
errBalancerClosed = errors.New("grpc: balancer is closed")
// minimum time to give a connection to complete
minConnectTimeout = 20 * time.Second
)
// dialOptions configure a Dial call. dialOptions are set by the DialOption
// values passed to Dial.
type dialOptions struct {
unaryInt UnaryClientInterceptor
streamInt StreamClientInterceptor
codec Codec
cp Compressor
dc Decompressor
bs backoffStrategy
balancer Balancer
block bool
insecure bool
timeout time.Duration
scChan <-chan ServiceConfig
copts transport.ConnectOptions
callOptions []CallOption
}
const (
defaultClientMaxReceiveMessageSize = 1024 * 1024 * 4
defaultClientMaxSendMessageSize = 1024 * 1024 * 4
)
// DialOption configures how we set up the connection.
type DialOption func(*dialOptions)
// WithInitialWindowSize returns a DialOption which sets the value for initial window size on a stream.
// The lower bound for window size is 64K and any value smaller than that will be ignored.
func WithInitialWindowSize(s int32) DialOption {
return func(o *dialOptions) {
o.copts.InitialWindowSize = s
}
}
// WithInitialConnWindowSize returns a DialOption which sets the value for initial window size on a connection.
// The lower bound for window size is 64K and any value smaller than that will be ignored.
func WithInitialConnWindowSize(s int32) DialOption {
return func(o *dialOptions) {
o.copts.InitialConnWindowSize = s
}
}
// WithMaxMsgSize returns a DialOption which sets the maximum message size the client can receive. Deprecated: use WithDefaultCallOptions(MaxCallRecvMsgSize(s)) instead.
func WithMaxMsgSize(s int) DialOption {
return WithDefaultCallOptions(MaxCallRecvMsgSize(s))
}
// WithDefaultCallOptions returns a DialOption which sets the default CallOptions for calls over the connection.
func WithDefaultCallOptions(cos ...CallOption) DialOption {
return func(o *dialOptions) {
o.callOptions = append(o.callOptions, cos...)
}
}
// WithCodec returns a DialOption which sets a codec for message marshaling and unmarshaling.
func WithCodec(c Codec) DialOption {
return func(o *dialOptions) {
o.codec = c
}
}
// WithCompressor returns a DialOption which sets a CompressorGenerator for generating message
// compressor.
func WithCompressor(cp Compressor) DialOption {
return func(o *dialOptions) {
o.cp = cp
}
}
// WithDecompressor returns a DialOption which sets a DecompressorGenerator for generating
// message decompressor.
func WithDecompressor(dc Decompressor) DialOption {
return func(o *dialOptions) {
o.dc = dc
}
}
// WithBalancer returns a DialOption which sets a load balancer.
func WithBalancer(b Balancer) DialOption {
return func(o *dialOptions) {
o.balancer = b
}
}
// WithServiceConfig returns a DialOption which has a channel to read the service configuration.
func WithServiceConfig(c <-chan ServiceConfig) DialOption {
return func(o *dialOptions) {
o.scChan = c
}
}
// WithBackoffMaxDelay configures the dialer to use the provided maximum delay
// when backing off after failed connection attempts.
func WithBackoffMaxDelay(md time.Duration) DialOption {
return WithBackoffConfig(BackoffConfig{MaxDelay: md})
}
// WithBackoffConfig configures the dialer to use the provided backoff
// parameters after connection failures.
//
// Use WithBackoffMaxDelay until more parameters on BackoffConfig are opened up
// for use.
func WithBackoffConfig(b BackoffConfig) DialOption {
// Set defaults to ensure that provided BackoffConfig is valid and
// unexported fields get default values.
setDefaults(&b)
return withBackoff(b)
}
// withBackoff sets the backoff strategy used for retries after a
// failed connection attempt.
//
// This can be exported if arbitrary backoff strategies are allowed by gRPC.
func withBackoff(bs backoffStrategy) DialOption {
return func(o *dialOptions) {
o.bs = bs
}
}
// WithBlock returns a DialOption which makes caller of Dial blocks until the underlying
// connection is up. Without this, Dial returns immediately and connecting the server
// happens in background.
func WithBlock() DialOption {
return func(o *dialOptions) {
o.block = true
}
}
// WithInsecure returns a DialOption which disables transport security for this ClientConn.
// Note that transport security is required unless WithInsecure is set.
func WithInsecure() DialOption {
return func(o *dialOptions) {
o.insecure = true
}
}
// WithTransportCredentials returns a DialOption which configures a
// connection level security credentials (e.g., TLS/SSL).
func WithTransportCredentials(creds credentials.TransportCredentials) DialOption {
return func(o *dialOptions) {
o.copts.TransportCredentials = creds
}
}
// WithPerRPCCredentials returns a DialOption which sets
// credentials and places auth state on each outbound RPC.
func WithPerRPCCredentials(creds credentials.PerRPCCredentials) DialOption {
return func(o *dialOptions) {
o.copts.PerRPCCredentials = append(o.copts.PerRPCCredentials, creds)
}
}
// WithTimeout returns a DialOption that configures a timeout for dialing a ClientConn
// initially. This is valid if and only if WithBlock() is present.
// Deprecated: use DialContext and context.WithTimeout instead.
func WithTimeout(d time.Duration) DialOption {
return func(o *dialOptions) {
o.timeout = d
}
}
// WithDialer returns a DialOption that specifies a function to use for dialing network addresses.
// If FailOnNonTempDialError() is set to true, and an error is returned by f, gRPC checks the error's
// Temporary() method to decide if it should try to reconnect to the network address.
func WithDialer(f func(string, time.Duration) (net.Conn, error)) DialOption {
return func(o *dialOptions) {
o.copts.Dialer = func(ctx context.Context, addr string) (net.Conn, error) {
if deadline, ok := ctx.Deadline(); ok {
return f(addr, deadline.Sub(time.Now()))
}
return f(addr, 0)
}
}
}
// WithStatsHandler returns a DialOption that specifies the stats handler
// for all the RPCs and underlying network connections in this ClientConn.
func WithStatsHandler(h stats.Handler) DialOption {
return func(o *dialOptions) {
o.copts.StatsHandler = h
}
}
// FailOnNonTempDialError returns a DialOption that specifies if gRPC fails on non-temporary dial errors.
// If f is true, and dialer returns a non-temporary error, gRPC will fail the connection to the network
// address and won't try to reconnect.
// The default value of FailOnNonTempDialError is false.
// This is an EXPERIMENTAL API.
func FailOnNonTempDialError(f bool) DialOption {
return func(o *dialOptions) {
o.copts.FailOnNonTempDialError = f
}
}
// WithUserAgent returns a DialOption that specifies a user agent string for all the RPCs.
func WithUserAgent(s string) DialOption {
return func(o *dialOptions) {
o.copts.UserAgent = s
}
}
// WithKeepaliveParams returns a DialOption that specifies keepalive paramaters for the client transport.
func WithKeepaliveParams(kp keepalive.ClientParameters) DialOption {
return func(o *dialOptions) {
o.copts.KeepaliveParams = kp
}
}
// WithUnaryInterceptor returns a DialOption that specifies the interceptor for unary RPCs.
func WithUnaryInterceptor(f UnaryClientInterceptor) DialOption {
return func(o *dialOptions) {
o.unaryInt = f
}
}
// WithStreamInterceptor returns a DialOption that specifies the interceptor for streaming RPCs.
func WithStreamInterceptor(f StreamClientInterceptor) DialOption {
return func(o *dialOptions) {
o.streamInt = f
}
}
// WithAuthority returns a DialOption that specifies the value to be used as
// the :authority pseudo-header. This value only works with WithInsecure and
// has no effect if TransportCredentials are present.
func WithAuthority(a string) DialOption {
return func(o *dialOptions) {
o.copts.Authority = a
}
}
// Dial creates a client connection to the given target.
func Dial(target string, opts ...DialOption) (*ClientConn, error) {
return DialContext(context.Background(), target, opts...)
}
// DialContext creates a client connection to the given target. ctx can be used to
// cancel or expire the pending connection. Once this function returns, the
// cancellation and expiration of ctx will be noop. Users should call ClientConn.Close
// to terminate all the pending operations after this function returns.
func DialContext(ctx context.Context, target string, opts ...DialOption) (conn *ClientConn, err error) {
cc := &ClientConn{
target: target,
conns: make(map[Address]*addrConn),
}
cc.ctx, cc.cancel = context.WithCancel(context.Background())
for _, opt := range opts {
opt(&cc.dopts)
}
cc.mkp = cc.dopts.copts.KeepaliveParams
if cc.dopts.copts.Dialer == nil {
cc.dopts.copts.Dialer = newProxyDialer(
func(ctx context.Context, addr string) (net.Conn, error) {
return dialContext(ctx, "tcp", addr)
},
)
}
if cc.dopts.copts.UserAgent != "" {
cc.dopts.copts.UserAgent += " " + grpcUA
} else {
cc.dopts.copts.UserAgent = grpcUA
}
if cc.dopts.timeout > 0 {
var cancel context.CancelFunc
ctx, cancel = context.WithTimeout(ctx, cc.dopts.timeout)
defer cancel()
}
defer func() {
select {
case <-ctx.Done():
conn, err = nil, ctx.Err()
default:
}
if err != nil {
cc.Close()
}
}()
scSet := false
if cc.dopts.scChan != nil {
// Try to get an initial service config.
select {
case sc, ok := <-cc.dopts.scChan:
if ok {
cc.sc = sc
scSet = true
}
default:
}
}
// Set defaults.
if cc.dopts.codec == nil {
cc.dopts.codec = protoCodec{}
}
if cc.dopts.bs == nil {
cc.dopts.bs = DefaultBackoffConfig
}
creds := cc.dopts.copts.TransportCredentials
if creds != nil && creds.Info().ServerName != "" {
cc.authority = creds.Info().ServerName
} else if cc.dopts.insecure && cc.dopts.copts.Authority != "" {
cc.authority = cc.dopts.copts.Authority
} else {
cc.authority = target
}
waitC := make(chan error, 1)
go func() {
defer close(waitC)
if cc.dopts.balancer == nil && cc.sc.LB != nil {
cc.dopts.balancer = cc.sc.LB
}
if cc.dopts.balancer != nil {
var credsClone credentials.TransportCredentials
if creds != nil {
credsClone = creds.Clone()
}
config := BalancerConfig{
DialCreds: credsClone,
Dialer: cc.dopts.copts.Dialer,
}
if err := cc.dopts.balancer.Start(target, config); err != nil {
waitC <- err
return
}
ch := cc.dopts.balancer.Notify()
if ch != nil {
if cc.dopts.block {
doneChan := make(chan struct{})
go cc.lbWatcher(doneChan)
<-doneChan
} else {
go cc.lbWatcher(nil)
}
return
}
}
// No balancer, or no resolver within the balancer. Connect directly.
if err := cc.resetAddrConn(Address{Addr: target}, cc.dopts.block, nil); err != nil {
waitC <- err
return
}
}()
select {
case <-ctx.Done():
return nil, ctx.Err()
case err := <-waitC:
if err != nil {
return nil, err
}
}
if cc.dopts.scChan != nil && !scSet {
// Blocking wait for the initial service config.
select {
case sc, ok := <-cc.dopts.scChan:
if ok {
cc.sc = sc
}
case <-ctx.Done():
return nil, ctx.Err()
}
}
if cc.dopts.scChan != nil {
go cc.scWatcher()
}
return cc, nil
}
// ConnectivityState indicates the state of a client connection.
type ConnectivityState int
const (
// Idle indicates the ClientConn is idle.
Idle ConnectivityState = iota
// Connecting indicates the ClienConn is connecting.
Connecting
// Ready indicates the ClientConn is ready for work.
Ready
// TransientFailure indicates the ClientConn has seen a failure but expects to recover.
TransientFailure
// Shutdown indicates the ClientConn has started shutting down.
Shutdown
)
func (s ConnectivityState) String() string {
switch s {
case Idle:
return "IDLE"
case Connecting:
return "CONNECTING"
case Ready:
return "READY"
case TransientFailure:
return "TRANSIENT_FAILURE"
case Shutdown:
return "SHUTDOWN"
default:
panic(fmt.Sprintf("unknown connectivity state: %d", s))
}
}
// ClientConn represents a client connection to an RPC server.
type ClientConn struct {
ctx context.Context
cancel context.CancelFunc
target string
authority string
dopts dialOptions
mu sync.RWMutex
sc ServiceConfig
conns map[Address]*addrConn
// Keepalive parameter can be updated if a GoAway is received.
mkp keepalive.ClientParameters
}
// lbWatcher watches the Notify channel of the balancer in cc and manages
// connections accordingly. If doneChan is not nil, it is closed after the
// first successfull connection is made.
func (cc *ClientConn) lbWatcher(doneChan chan struct{}) {
for addrs := range cc.dopts.balancer.Notify() {
var (
add []Address // Addresses need to setup connections.
del []*addrConn // Connections need to tear down.
)
cc.mu.Lock()
for _, a := range addrs {
if _, ok := cc.conns[a]; !ok {
add = append(add, a)
}
}
for k, c := range cc.conns {
var keep bool
for _, a := range addrs {
if k == a {
keep = true
break
}
}
if !keep {
del = append(del, c)
delete(cc.conns, c.addr)
}
}
cc.mu.Unlock()
for _, a := range add {
if doneChan != nil {
err := cc.resetAddrConn(a, true, nil)
if err == nil {
close(doneChan)
doneChan = nil
}
} else {
cc.resetAddrConn(a, false, nil)
}
}
for _, c := range del {
c.tearDown(errConnDrain)
}
}
}
func (cc *ClientConn) scWatcher() {
for {
select {
case sc, ok := <-cc.dopts.scChan:
if !ok {
return
}
cc.mu.Lock()
// TODO: load balance policy runtime change is ignored.
// We may revist this decision in the future.
cc.sc = sc
cc.mu.Unlock()
case <-cc.ctx.Done():
return
}
}
}
// resetAddrConn creates an addrConn for addr and adds it to cc.conns.
// If there is an old addrConn for addr, it will be torn down, using tearDownErr as the reason.
// If tearDownErr is nil, errConnDrain will be used instead.
//
// We should never need to replace an addrConn with a new one. This function is only used
// as newAddrConn to create new addrConn.
// TODO rename this function and clean up the code.
func (cc *ClientConn) resetAddrConn(addr Address, block bool, tearDownErr error) error {
ac := &addrConn{
cc: cc,
addr: addr,
dopts: cc.dopts,
}
ac.ctx, ac.cancel = context.WithCancel(cc.ctx)
ac.stateCV = sync.NewCond(&ac.mu)
if EnableTracing {
ac.events = trace.NewEventLog("grpc.ClientConn", ac.addr.Addr)
}
if !ac.dopts.insecure {
if ac.dopts.copts.TransportCredentials == nil {
return errNoTransportSecurity
}
} else {
if ac.dopts.copts.TransportCredentials != nil {
return errCredentialsConflict
}
for _, cd := range ac.dopts.copts.PerRPCCredentials {
if cd.RequireTransportSecurity() {
return errTransportCredentialsMissing
}
}
}
// Track ac in cc. This needs to be done before any getTransport(...) is called.
cc.mu.Lock()
if cc.conns == nil {
cc.mu.Unlock()
return ErrClientConnClosing
}
stale := cc.conns[ac.addr]
cc.conns[ac.addr] = ac
cc.mu.Unlock()
if stale != nil {
// There is an addrConn alive on ac.addr already. This could be due to
// a buggy Balancer that reports duplicated Addresses.
if tearDownErr == nil {
// tearDownErr is nil if resetAddrConn is called by
// 1) Dial
// 2) lbWatcher
// In both cases, the stale ac should drain, not close.
stale.tearDown(errConnDrain)
} else {
stale.tearDown(tearDownErr)
}
}
if block {
if err := ac.resetTransport(false); err != nil {
if err != errConnClosing {
// Tear down ac and delete it from cc.conns.
cc.mu.Lock()
delete(cc.conns, ac.addr)
cc.mu.Unlock()
ac.tearDown(err)
}
if e, ok := err.(transport.ConnectionError); ok && !e.Temporary() {
return e.Origin()
}
return err
}
// Start to monitor the error status of transport.
go ac.transportMonitor()
} else {
// Start a goroutine connecting to the server asynchronously.
go func() {
if err := ac.resetTransport(false); err != nil {
grpclog.Warningf("Failed to dial %s: %v; please retry.", ac.addr.Addr, err)
if err != errConnClosing {
// Keep this ac in cc.conns, to get the reason it's torn down.
ac.tearDown(err)
}
return
}
ac.transportMonitor()
}()
}
return nil
}
// GetMethodConfig gets the method config of the input method.
// If there's an exact match for input method (i.e. /service/method), we return
// the corresponding MethodConfig.
// If there isn't an exact match for the input method, we look for the default config
// under the service (i.e /service/). If there is a default MethodConfig for
// the serivce, we return it.
// Otherwise, we return an empty MethodConfig.
func (cc *ClientConn) GetMethodConfig(method string) MethodConfig {
// TODO: Avoid the locking here.
cc.mu.RLock()
defer cc.mu.RUnlock()
m, ok := cc.sc.Methods[method]
if !ok {
i := strings.LastIndex(method, "/")
m, _ = cc.sc.Methods[method[:i+1]]
}
return m
}
func (cc *ClientConn) getTransport(ctx context.Context, opts BalancerGetOptions) (transport.ClientTransport, func(), error) {
var (
ac *addrConn
ok bool
put func()
)
if cc.dopts.balancer == nil {
// If balancer is nil, there should be only one addrConn available.
cc.mu.RLock()
if cc.conns == nil {
cc.mu.RUnlock()
return nil, nil, toRPCErr(ErrClientConnClosing)
}
for _, ac = range cc.conns {
// Break after the first iteration to get the first addrConn.
ok = true
break
}
cc.mu.RUnlock()
} else {
var (
addr Address
err error
)
addr, put, err = cc.dopts.balancer.Get(ctx, opts)
if err != nil {
return nil, nil, toRPCErr(err)
}
cc.mu.RLock()
if cc.conns == nil {
cc.mu.RUnlock()
return nil, nil, toRPCErr(ErrClientConnClosing)
}
ac, ok = cc.conns[addr]
cc.mu.RUnlock()
}
if !ok {
if put != nil {
updateRPCInfoInContext(ctx, rpcInfo{bytesSent: false, bytesReceived: false})
put()
}
return nil, nil, errConnClosing
}
t, err := ac.wait(ctx, cc.dopts.balancer != nil, !opts.BlockingWait)
if err != nil {
if put != nil {
updateRPCInfoInContext(ctx, rpcInfo{bytesSent: false, bytesReceived: false})
put()
}
return nil, nil, err
}
return t, put, nil
}
// Close tears down the ClientConn and all underlying connections.
func (cc *ClientConn) Close() error {
cc.cancel()
cc.mu.Lock()
if cc.conns == nil {
cc.mu.Unlock()
return ErrClientConnClosing
}
conns := cc.conns
cc.conns = nil
cc.mu.Unlock()
if cc.dopts.balancer != nil {
cc.dopts.balancer.Close()
}
for _, ac := range conns {
ac.tearDown(ErrClientConnClosing)
}
return nil
}
// addrConn is a network connection to a given address.
type addrConn struct {
ctx context.Context
cancel context.CancelFunc
cc *ClientConn
addr Address
dopts dialOptions
events trace.EventLog
mu sync.Mutex
state ConnectivityState
stateCV *sync.Cond
down func(error) // the handler called when a connection is down.
// ready is closed and becomes nil when a new transport is up or failed
// due to timeout.
ready chan struct{}
transport transport.ClientTransport
// The reason this addrConn is torn down.
tearDownErr error
}
// adjustParams updates parameters used to create transports upon
// receiving a GoAway.
func (ac *addrConn) adjustParams(r transport.GoAwayReason) {
switch r {
case transport.TooManyPings:
v := 2 * ac.dopts.copts.KeepaliveParams.Time
ac.cc.mu.Lock()
if v > ac.cc.mkp.Time {
ac.cc.mkp.Time = v
}
ac.cc.mu.Unlock()
}
}
// printf records an event in ac's event log, unless ac has been closed.
// REQUIRES ac.mu is held.
func (ac *addrConn) printf(format string, a ...interface{}) {
if ac.events != nil {
ac.events.Printf(format, a...)
}
}
// errorf records an error in ac's event log, unless ac has been closed.
// REQUIRES ac.mu is held.
func (ac *addrConn) errorf(format string, a ...interface{}) {
if ac.events != nil {
ac.events.Errorf(format, a...)
}
}
// getState returns the connectivity state of the Conn
func (ac *addrConn) getState() ConnectivityState {
ac.mu.Lock()
defer ac.mu.Unlock()
return ac.state
}
// waitForStateChange blocks until the state changes to something other than the sourceState.
func (ac *addrConn) waitForStateChange(ctx context.Context, sourceState ConnectivityState) (ConnectivityState, error) {
ac.mu.Lock()
defer ac.mu.Unlock()
if sourceState != ac.state {
return ac.state, nil
}
done := make(chan struct{})
var err error
go func() {
select {
case <-ctx.Done():
ac.mu.Lock()
err = ctx.Err()
ac.stateCV.Broadcast()
ac.mu.Unlock()
case <-done:
}
}()
defer close(done)
for sourceState == ac.state {
ac.stateCV.Wait()
if err != nil {
return ac.state, err
}
}
return ac.state, nil
}
// resetTransport recreates a transport to the address for ac.
// For the old transport:
// - if drain is true, it will be gracefully closed.
// - otherwise, it will be closed.
func (ac *addrConn) resetTransport(drain bool) error {
ac.mu.Lock()
if ac.state == Shutdown {
ac.mu.Unlock()
return errConnClosing
}
ac.printf("connecting")
if ac.down != nil {
ac.down(downErrorf(false, true, "%v", errNetworkIO))
ac.down = nil
}
ac.state = Connecting
ac.stateCV.Broadcast()
t := ac.transport
ac.transport = nil
ac.mu.Unlock()
if t != nil {
if drain {
t.GracefulClose()
} else {
t.Close()
}
}
ac.cc.mu.RLock()
ac.dopts.copts.KeepaliveParams = ac.cc.mkp
ac.cc.mu.RUnlock()
for retries := 0; ; retries++ {
ac.mu.Lock()
if ac.state == Shutdown {
// ac.tearDown(...) has been invoked.
ac.mu.Unlock()
return errConnClosing
}
ac.mu.Unlock()
sleepTime := ac.dopts.bs.backoff(retries)
timeout := minConnectTimeout
if timeout < sleepTime {
timeout = sleepTime
}
ctx, cancel := context.WithTimeout(ac.ctx, timeout)
connectTime := time.Now()
sinfo := transport.TargetInfo{
Addr: ac.addr.Addr,
Metadata: ac.addr.Metadata,
}
newTransport, err := transport.NewClientTransport(ctx, sinfo, ac.dopts.copts)
// Don't call cancel in success path due to a race in Go 1.6:
// https://github.com/golang/go/issues/15078.
if err != nil {
cancel()
if e, ok := err.(transport.ConnectionError); ok && !e.Temporary() {
return err
}
grpclog.Warningf("grpc: addrConn.resetTransport failed to create client transport: %v; Reconnecting to %v", err, ac.addr)
ac.mu.Lock()
if ac.state == Shutdown {
// ac.tearDown(...) has been invoked.
ac.mu.Unlock()
return errConnClosing
}
ac.errorf("transient failure: %v", err)
ac.state = TransientFailure
ac.stateCV.Broadcast()
if ac.ready != nil {
close(ac.ready)
ac.ready = nil
}
ac.mu.Unlock()
timer := time.NewTimer(sleepTime - time.Since(connectTime))
select {
case <-timer.C:
case <-ac.ctx.Done():
timer.Stop()
return ac.ctx.Err()
}
timer.Stop()
continue
}
ac.mu.Lock()
ac.printf("ready")
if ac.state == Shutdown {
// ac.tearDown(...) has been invoked.
ac.mu.Unlock()
newTransport.Close()
return errConnClosing
}
ac.state = Ready
ac.stateCV.Broadcast()
ac.transport = newTransport
if ac.ready != nil {
close(ac.ready)
ac.ready = nil
}
if ac.cc.dopts.balancer != nil {
ac.down = ac.cc.dopts.balancer.Up(ac.addr)
}
ac.mu.Unlock()
return nil
}
}
// Run in a goroutine to track the error in transport and create the
// new transport if an error happens. It returns when the channel is closing.
func (ac *addrConn) transportMonitor() {
for {
ac.mu.Lock()
t := ac.transport
ac.mu.Unlock()
select {
// This is needed to detect the teardown when
// the addrConn is idle (i.e., no RPC in flight).
case <-ac.ctx.Done():
select {
case <-t.Error():
t.Close()
default:
}
return
case <-t.GoAway():
ac.adjustParams(t.GetGoAwayReason())
// If GoAway happens without any network I/O error, the underlying transport
// will be gracefully closed, and a new transport will be created.
// (The transport will be closed when all the pending RPCs finished or failed.)
// If GoAway and some network I/O error happen concurrently, the underlying transport
// will be closed, and a new transport will be created.
var drain bool
select {
case <-t.Error():
default:
drain = true
}
if err := ac.resetTransport(drain); err != nil {
grpclog.Infof("get error from resetTransport %v, transportMonitor returning", err)
if err != errConnClosing {
// Keep this ac in cc.conns, to get the reason it's torn down.
ac.tearDown(err)
}
return
}
case <-t.Error():
select {
case <-ac.ctx.Done():
t.Close()
return
case <-t.GoAway():
ac.adjustParams(t.GetGoAwayReason())
if err := ac.resetTransport(false); err != nil {
grpclog.Infof("get error from resetTransport %v, transportMonitor returning", err)
if err != errConnClosing {
// Keep this ac in cc.conns, to get the reason it's torn down.
ac.tearDown(err)
}
return
}
default:
}
ac.mu.Lock()
if ac.state == Shutdown {
// ac has been shutdown.
ac.mu.Unlock()
return
}
ac.state = TransientFailure
ac.stateCV.Broadcast()
ac.mu.Unlock()
if err := ac.resetTransport(false); err != nil {
grpclog.Infof("get error from resetTransport %v, transportMonitor returning", err)
ac.mu.Lock()
ac.printf("transport exiting: %v", err)
ac.mu.Unlock()
grpclog.Warningf("grpc: addrConn.transportMonitor exits due to: %v", err)
if err != errConnClosing {
// Keep this ac in cc.conns, to get the reason it's torn down.
ac.tearDown(err)
}
return
}
}
}
}
// wait blocks until i) the new transport is up or ii) ctx is done or iii) ac is closed or
// iv) transport is in TransientFailure and there is a balancer/failfast is true.
func (ac *addrConn) wait(ctx context.Context, hasBalancer, failfast bool) (transport.ClientTransport, error) {
for {
ac.mu.Lock()
switch {
case ac.state == Shutdown:
if failfast || !hasBalancer {
// RPC is failfast or balancer is nil. This RPC should fail with ac.tearDownErr.
err := ac.tearDownErr
ac.mu.Unlock()
return nil, err
}
ac.mu.Unlock()
return nil, errConnClosing
case ac.state == Ready:
ct := ac.transport
ac.mu.Unlock()
return ct, nil
case ac.state == TransientFailure:
if failfast || hasBalancer {
ac.mu.Unlock()
return nil, errConnUnavailable
}
}
ready := ac.ready
if ready == nil {
ready = make(chan struct{})
ac.ready = ready
}
ac.mu.Unlock()
select {
case <-ctx.Done():
return nil, toRPCErr(ctx.Err())
// Wait until the new transport is ready or failed.
case <-ready:
}
}
}
// tearDown starts to tear down the addrConn.
// TODO(zhaoq): Make this synchronous to avoid unbounded memory consumption in
// some edge cases (e.g., the caller opens and closes many addrConn's in a
// tight loop.
// tearDown doesn't remove ac from ac.cc.conns.
func (ac *addrConn) tearDown(err error) {
ac.cancel()
ac.mu.Lock()
defer ac.mu.Unlock()
if ac.down != nil {
ac.down(downErrorf(false, false, "%v", err))
ac.down = nil
}
if err == errConnDrain && ac.transport != nil {
// GracefulClose(...) may be executed multiple times when
// i) receiving multiple GoAway frames from the server; or
// ii) there are concurrent name resolver/Balancer triggered
// address removal and GoAway.
ac.transport.GracefulClose()
}
if ac.state == Shutdown {
return
}
ac.state = Shutdown
ac.tearDownErr = err
ac.stateCV.Broadcast()
if ac.events != nil {
ac.events.Finish()
ac.events = nil
}
if ac.ready != nil {
close(ac.ready)
ac.ready = nil
}
if ac.transport != nil && err != errConnDrain {
ac.transport.Close()
}
return
}