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

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/*
*
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* Copyright 2014 gRPC authors.
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*
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* 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
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* 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.
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*
*/
package grpc
import (
"errors"
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"fmt"
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"math"
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"net"
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"reflect"
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"strings"
"sync"
"time"
"golang.org/x/net/context"
"golang.org/x/net/trace"
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"google.golang.org/grpc/balancer"
_ "google.golang.org/grpc/balancer/roundrobin" // To register roundrobin.
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"google.golang.org/grpc/connectivity"
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"google.golang.org/grpc/credentials"
"google.golang.org/grpc/grpclog"
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"google.golang.org/grpc/keepalive"
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"google.golang.org/grpc/resolver"
_ "google.golang.org/grpc/resolver/dns" // To register dns resolver.
_ "google.golang.org/grpc/resolver/passthrough" // To register passthrough resolver.
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"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.
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// DEPRECATED: Please use context.DeadlineExceeded instead.
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ErrClientConnTimeout = errors.New("grpc: timed out when dialing")
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// 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
)
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// The following errors are returned from Dial and DialContext
var (
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// 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")
)
// dialOptions configure a Dial call. dialOptions are set by the DialOption
// values passed to Dial.
type dialOptions struct {
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unaryInt UnaryClientInterceptor
streamInt StreamClientInterceptor
codec Codec
cp Compressor
dc Decompressor
bs backoffStrategy
block bool
insecure bool
timeout time.Duration
scChan <-chan ServiceConfig
copts transport.ConnectOptions
callOptions []CallOption
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// This is used by v1 balancer dial option WithBalancer to support v1
// balancer, and also by WithBalancerName dial option.
balancerBuilder balancer.Builder
// This is to support grpclb.
resolverBuilder resolver.Builder
// Custom user options for resolver.Build.
resolverBuildUserOptions interface{}
waitForHandshake bool
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}
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const (
defaultClientMaxReceiveMessageSize = 1024 * 1024 * 4
defaultClientMaxSendMessageSize = math.MaxInt32
)
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// DialOption configures how we set up the connection.
type DialOption func(*dialOptions)
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// WithWaitForHandshake blocks until the initial settings frame is received from the
// server before assigning RPCs to the connection.
// Experimental API.
func WithWaitForHandshake() DialOption {
return func(o *dialOptions) {
o.waitForHandshake = true
}
}
// WithWriteBufferSize lets you set the size of write buffer, this determines how much data can be batched
// before doing a write on the wire.
func WithWriteBufferSize(s int) DialOption {
return func(o *dialOptions) {
o.copts.WriteBufferSize = s
}
}
// WithReadBufferSize lets you set the size of read buffer, this determines how much data can be read at most
// for each read syscall.
func WithReadBufferSize(s int) DialOption {
return func(o *dialOptions) {
o.copts.ReadBufferSize = s
}
}
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// 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...)
}
}
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// 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
}
}
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// WithCompressor returns a DialOption which sets a Compressor to use for
// message compression. It has lower priority than the compressor set by
// the UseCompressor CallOption.
//
// Deprecated: use UseCompressor instead.
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func WithCompressor(cp Compressor) DialOption {
return func(o *dialOptions) {
o.cp = cp
}
}
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// WithDecompressor returns a DialOption which sets a Decompressor to use for
// incoming message decompression. If incoming response messages are encoded
// using the decompressor's Type(), it will be used. Otherwise, the message
// encoding will be used to look up the compressor registered via
// encoding.RegisterCompressor, which will then be used to decompress the
// message. If no compressor is registered for the encoding, an Unimplemented
// status error will be returned.
//
// Deprecated: use encoding.RegisterCompressor instead.
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func WithDecompressor(dc Decompressor) DialOption {
return func(o *dialOptions) {
o.dc = dc
}
}
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// WithBalancer returns a DialOption which sets a load balancer with the v1 API.
// Name resolver will be ignored if this DialOption is specified.
//
// Deprecated: use the new balancer APIs in balancer package and WithBalancerName.
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func WithBalancer(b Balancer) DialOption {
return func(o *dialOptions) {
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o.balancerBuilder = &balancerWrapperBuilder{
b: b,
}
}
}
// WithBalancerName sets the balancer that the ClientConn will be initialized
// with. Balancer registered with balancerName will be used. This function
// panics if no balancer was registered by balancerName.
//
// The balancer cannot be overridden by balancer option specified by service
// config.
//
// This is an EXPERIMENTAL API.
func WithBalancerName(balancerName string) DialOption {
builder := balancer.Get(balancerName)
if builder == nil {
panic(fmt.Sprintf("grpc.WithBalancerName: no balancer is registered for name %v", balancerName))
}
return func(o *dialOptions) {
o.balancerBuilder = builder
}
}
// withResolverBuilder is only for grpclb.
func withResolverBuilder(b resolver.Builder) DialOption {
return func(o *dialOptions) {
o.resolverBuilder = b
}
}
// WithResolverUserOptions returns a DialOption which sets the UserOptions
// field of resolver's BuildOption.
func WithResolverUserOptions(userOpt interface{}) DialOption {
return func(o *dialOptions) {
o.resolverBuildUserOptions = userOpt
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}
}
// WithServiceConfig returns a DialOption which has a channel to read the service configuration.
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// DEPRECATED: service config should be received through name resolver, as specified here.
// https://github.com/grpc/grpc/blob/master/doc/service_config.md
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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)
}
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// withBackoff sets the backoff strategy used for connectRetryNum after a
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// 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
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// credentials and places auth state on each outbound RPC.
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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.
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// Deprecated: use DialContext and context.WithTimeout instead.
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func WithTimeout(d time.Duration) DialOption {
return func(o *dialOptions) {
o.timeout = d
}
}
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func withContextDialer(f func(context.Context, string) (net.Conn, error)) DialOption {
return func(o *dialOptions) {
o.copts.Dialer = f
}
}
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// 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 {
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return withContextDialer(
func(ctx context.Context, addr string) (net.Conn, error) {
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if deadline, ok := ctx.Deadline(); ok {
return f(addr, deadline.Sub(time.Now()))
}
return f(addr, 0)
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})
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}
// 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
}
}
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// FailOnNonTempDialError returns a DialOption that specifies if gRPC fails on non-temporary dial errors.
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// 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
}
}
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// WithKeepaliveParams returns a DialOption that specifies keepalive parameters for the client transport.
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func WithKeepaliveParams(kp keepalive.ClientParameters) DialOption {
return func(o *dialOptions) {
o.copts.KeepaliveParams = kp
}
}
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// 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
}
}
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// 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
}
}
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// 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
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// cancel or expire the pending connection. Once this function returns, the
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// 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,
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csMgr: &connectivityStateManager{},
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conns: make(map[*addrConn]struct{}),
blockingpicker: newPickerWrapper(),
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}
cc.ctx, cc.cancel = context.WithCancel(context.Background())
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for _, opt := range opts {
opt(&cc.dopts)
}
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if !cc.dopts.insecure {
if cc.dopts.copts.TransportCredentials == nil {
return nil, errNoTransportSecurity
}
} else {
if cc.dopts.copts.TransportCredentials != nil {
return nil, errCredentialsConflict
}
for _, cd := range cc.dopts.copts.PerRPCCredentials {
if cd.RequireTransportSecurity() {
return nil, errTransportCredentialsMissing
}
}
}
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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
}
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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()
}
}()
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scSet := false
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if cc.dopts.scChan != nil {
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// Try to get an initial service config.
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select {
case sc, ok := <-cc.dopts.scChan:
if ok {
cc.sc = sc
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scSet = true
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}
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default:
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}
}
// Set defaults.
if cc.dopts.codec == nil {
cc.dopts.codec = protoCodec{}
}
if cc.dopts.bs == nil {
cc.dopts.bs = DefaultBackoffConfig
}
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cc.parsedTarget = parseTarget(cc.target)
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creds := cc.dopts.copts.TransportCredentials
if creds != nil && creds.Info().ServerName != "" {
cc.authority = creds.Info().ServerName
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} else if cc.dopts.insecure && cc.dopts.copts.Authority != "" {
cc.authority = cc.dopts.copts.Authority
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} else {
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// Use endpoint from "scheme://authority/endpoint" as the default
// authority for ClientConn.
cc.authority = cc.parsedTarget.Endpoint
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}
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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()
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}
}
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if cc.dopts.scChan != nil {
go cc.scWatcher()
}
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var credsClone credentials.TransportCredentials
if creds := cc.dopts.copts.TransportCredentials; creds != nil {
credsClone = creds.Clone()
}
cc.balancerBuildOpts = balancer.BuildOptions{
DialCreds: credsClone,
Dialer: cc.dopts.copts.Dialer,
}
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// Build the resolver.
cc.resolverWrapper, err = newCCResolverWrapper(cc)
if err != nil {
return nil, fmt.Errorf("failed to build resolver: %v", err)
}
// Start the resolver wrapper goroutine after resolverWrapper is created.
//
// If the goroutine is started before resolverWrapper is ready, the
// following may happen: The goroutine sends updates to cc. cc forwards
// those to balancer. Balancer creates new addrConn. addrConn fails to
// connect, and calls resolveNow(). resolveNow() tries to use the non-ready
// resolverWrapper.
cc.resolverWrapper.start()
// A blocking dial blocks until the clientConn is ready.
if cc.dopts.block {
for {
s := cc.GetState()
if s == connectivity.Ready {
break
}
if !cc.WaitForStateChange(ctx, s) {
// ctx got timeout or canceled.
return nil, ctx.Err()
}
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}
}
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return cc, nil
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}
// connectivityStateManager keeps the connectivity.State of ClientConn.
// This struct will eventually be exported so the balancers can access it.
type connectivityStateManager struct {
mu sync.Mutex
state connectivity.State
notifyChan chan struct{}
}
// updateState updates the connectivity.State of ClientConn.
// If there's a change it notifies goroutines waiting on state change to
// happen.
func (csm *connectivityStateManager) updateState(state connectivity.State) {
csm.mu.Lock()
defer csm.mu.Unlock()
if csm.state == connectivity.Shutdown {
return
}
if csm.state == state {
return
}
csm.state = state
if csm.notifyChan != nil {
// There are other goroutines waiting on this channel.
close(csm.notifyChan)
csm.notifyChan = nil
}
}
func (csm *connectivityStateManager) getState() connectivity.State {
csm.mu.Lock()
defer csm.mu.Unlock()
return csm.state
}
func (csm *connectivityStateManager) getNotifyChan() <-chan struct{} {
csm.mu.Lock()
defer csm.mu.Unlock()
if csm.notifyChan == nil {
csm.notifyChan = make(chan struct{})
}
return csm.notifyChan
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}
// ClientConn represents a client connection to an RPC server.
type ClientConn struct {
ctx context.Context
cancel context.CancelFunc
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target string
parsedTarget resolver.Target
authority string
dopts dialOptions
csMgr *connectivityStateManager
balancerBuildOpts balancer.BuildOptions
resolverWrapper *ccResolverWrapper
blockingpicker *pickerWrapper
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mu sync.RWMutex
sc ServiceConfig
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scRaw string
conns map[*addrConn]struct{}
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// Keepalive parameter can be updated if a GoAway is received.
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mkp keepalive.ClientParameters
curBalancerName string
preBalancerName string // previous balancer name.
curAddresses []resolver.Address
balancerWrapper *ccBalancerWrapper
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}
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// WaitForStateChange waits until the connectivity.State of ClientConn changes from sourceState or
// ctx expires. A true value is returned in former case and false in latter.
// This is an EXPERIMENTAL API.
func (cc *ClientConn) WaitForStateChange(ctx context.Context, sourceState connectivity.State) bool {
ch := cc.csMgr.getNotifyChan()
if cc.csMgr.getState() != sourceState {
return true
}
select {
case <-ctx.Done():
return false
case <-ch:
return true
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}
}
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// GetState returns the connectivity.State of ClientConn.
// This is an EXPERIMENTAL API.
func (cc *ClientConn) GetState() connectivity.State {
return cc.csMgr.getState()
}
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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
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cc.scRaw = ""
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cc.mu.Unlock()
case <-cc.ctx.Done():
return
}
}
}
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func (cc *ClientConn) handleResolvedAddrs(addrs []resolver.Address, err error) {
cc.mu.Lock()
defer cc.mu.Unlock()
if cc.conns == nil {
// cc was closed.
return
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}
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if reflect.DeepEqual(cc.curAddresses, addrs) {
return
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}
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cc.curAddresses = addrs
if cc.dopts.balancerBuilder == nil {
// Only look at balancer types and switch balancer if balancer dial
// option is not set.
var isGRPCLB bool
for _, a := range addrs {
if a.Type == resolver.GRPCLB {
isGRPCLB = true
break
}
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}
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var newBalancerName string
if isGRPCLB {
newBalancerName = grpclbName
} else {
// Address list doesn't contain grpclb address. Try to pick a
// non-grpclb balancer.
newBalancerName = cc.curBalancerName
// If current balancer is grpclb, switch to the previous one.
if newBalancerName == grpclbName {
newBalancerName = cc.preBalancerName
}
// The following could be true in two cases:
// - the first time handling resolved addresses
// (curBalancerName="")
// - the first time handling non-grpclb addresses
// (curBalancerName="grpclb", preBalancerName="")
if newBalancerName == "" {
newBalancerName = PickFirstBalancerName
}
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}
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cc.switchBalancer(newBalancerName)
} else if cc.balancerWrapper == nil {
// Balancer dial option was set, and this is the first time handling
// resolved addresses. Build a balancer with dopts.balancerBuilder.
cc.balancerWrapper = newCCBalancerWrapper(cc, cc.dopts.balancerBuilder, cc.balancerBuildOpts)
2017-10-06 15:29:20 +00:00
}
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cc.balancerWrapper.handleResolvedAddrs(addrs, nil)
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}
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// switchBalancer starts the switching from current balancer to the balancer
// with the given name.
//
// It will NOT send the current address list to the new balancer. If needed,
// caller of this function should send address list to the new balancer after
// this function returns.
//
// Caller must hold cc.mu.
func (cc *ClientConn) switchBalancer(name string) {
if cc.conns == nil {
return
}
if strings.ToLower(cc.curBalancerName) == strings.ToLower(name) {
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return
}
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grpclog.Infof("ClientConn switching balancer to %q", name)
if cc.dopts.balancerBuilder != nil {
grpclog.Infoln("ignoring balancer switching: Balancer DialOption used instead")
return
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}
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// TODO(bar switching) change this to two steps: drain and close.
// Keep track of sc in wrapper.
if cc.balancerWrapper != nil {
cc.balancerWrapper.close()
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}
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builder := balancer.Get(name)
if builder == nil {
grpclog.Infof("failed to get balancer builder for: %v, using pick_first instead", name)
builder = newPickfirstBuilder()
}
cc.preBalancerName = cc.curBalancerName
cc.curBalancerName = builder.Name()
cc.balancerWrapper = newCCBalancerWrapper(cc, builder, cc.balancerBuildOpts)
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}
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func (cc *ClientConn) handleSubConnStateChange(sc balancer.SubConn, s connectivity.State) {
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cc.mu.Lock()
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if cc.conns == nil {
cc.mu.Unlock()
return
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}
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// TODO(bar switching) send updates to all balancer wrappers when balancer
// gracefully switching is supported.
cc.balancerWrapper.handleSubConnStateChange(sc, s)
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cc.mu.Unlock()
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}
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// newAddrConn creates an addrConn for addrs and adds it to cc.conns.
//
// Caller needs to make sure len(addrs) > 0.
func (cc *ClientConn) newAddrConn(addrs []resolver.Address) (*addrConn, error) {
2017-10-06 15:29:20 +00:00
ac := &addrConn{
cc: cc,
addrs: addrs,
dopts: cc.dopts,
}
ac.ctx, ac.cancel = context.WithCancel(cc.ctx)
// Track ac in cc. This needs to be done before any getTransport(...) is called.
cc.mu.Lock()
if cc.conns == nil {
cc.mu.Unlock()
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return nil, ErrClientConnClosing
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}
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cc.conns[ac] = struct{}{}
cc.mu.Unlock()
return ac, nil
}
// removeAddrConn removes the addrConn in the subConn from clientConn.
// It also tears down the ac with the given error.
func (cc *ClientConn) removeAddrConn(ac *addrConn, err error) {
cc.mu.Lock()
if cc.conns == nil {
cc.mu.Unlock()
return
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}
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delete(cc.conns, ac)
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cc.mu.Unlock()
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ac.tearDown(err)
}
// connect starts to creating transport and also starts the transport monitor
// goroutine for this ac.
// It does nothing if the ac is not IDLE.
// TODO(bar) Move this to the addrConn section.
// This was part of resetAddrConn, keep it here to make the diff look clean.
func (ac *addrConn) connect() error {
ac.mu.Lock()
if ac.state == connectivity.Shutdown {
ac.mu.Unlock()
return errConnClosing
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}
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if ac.state != connectivity.Idle {
ac.mu.Unlock()
return nil
}
ac.state = connectivity.Connecting
ac.cc.handleSubConnStateChange(ac.acbw, ac.state)
ac.mu.Unlock()
// Start a goroutine connecting to the server asynchronously.
go func() {
if err := ac.resetTransport(); err != nil {
grpclog.Warningf("Failed to dial %s: %v; please retry.", ac.addrs[0].Addr, err)
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if err != errConnClosing {
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// Keep this ac in cc.conns, to get the reason it's torn down.
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ac.tearDown(err)
}
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return
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}
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ac.transportMonitor()
}()
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return nil
}
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// tryUpdateAddrs tries to update ac.addrs with the new addresses list.
//
// It checks whether current connected address of ac is in the new addrs list.
// - If true, it updates ac.addrs and returns true. The ac will keep using
// the existing connection.
// - If false, it does nothing and returns false.
func (ac *addrConn) tryUpdateAddrs(addrs []resolver.Address) bool {
ac.mu.Lock()
defer ac.mu.Unlock()
grpclog.Infof("addrConn: tryUpdateAddrs curAddr: %v, addrs: %v", ac.curAddr, addrs)
if ac.state == connectivity.Shutdown {
ac.addrs = addrs
return true
}
var curAddrFound bool
for _, a := range addrs {
if reflect.DeepEqual(ac.curAddr, a) {
curAddrFound = true
break
}
}
grpclog.Infof("addrConn: tryUpdateAddrs curAddrFound: %v", curAddrFound)
if curAddrFound {
ac.addrs = addrs
ac.reconnectIdx = 0 // Start reconnecting from beginning in the new list.
}
return curAddrFound
}
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// 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.
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cc.mu.RLock()
defer cc.mu.RUnlock()
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m, ok := cc.sc.Methods[method]
if !ok {
i := strings.LastIndex(method, "/")
m, _ = cc.sc.Methods[method[:i+1]]
}
return m
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}
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func (cc *ClientConn) getTransport(ctx context.Context, failfast bool) (transport.ClientTransport, func(balancer.DoneInfo), error) {
t, done, err := cc.blockingpicker.pick(ctx, failfast, balancer.PickOptions{})
if err != nil {
return nil, nil, toRPCErr(err)
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}
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return t, done, nil
}
// handleServiceConfig parses the service config string in JSON format to Go native
// struct ServiceConfig, and store both the struct and the JSON string in ClientConn.
func (cc *ClientConn) handleServiceConfig(js string) error {
sc, err := parseServiceConfig(js)
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if err != nil {
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return err
}
cc.mu.Lock()
cc.scRaw = js
cc.sc = sc
if sc.LB != nil && *sc.LB != grpclbName { // "grpclb" is not a valid balancer option in service config.
if cc.curBalancerName == grpclbName {
// If current balancer is grpclb, there's at least one grpclb
// balancer address in the resolved list. Don't switch the balancer,
// but change the previous balancer name, so if a new resolved
// address list doesn't contain grpclb address, balancer will be
// switched to *sc.LB.
cc.preBalancerName = *sc.LB
} else {
cc.switchBalancer(*sc.LB)
cc.balancerWrapper.handleResolvedAddrs(cc.curAddresses, nil)
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}
}
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cc.mu.Unlock()
return nil
}
func (cc *ClientConn) resolveNow(o resolver.ResolveNowOption) {
cc.mu.Lock()
r := cc.resolverWrapper
cc.mu.Unlock()
if r == nil {
return
}
go r.resolveNow(o)
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}
// 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
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cc.csMgr.updateState(connectivity.Shutdown)
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rWrapper := cc.resolverWrapper
cc.resolverWrapper = nil
bWrapper := cc.balancerWrapper
cc.balancerWrapper = nil
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cc.mu.Unlock()
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cc.blockingpicker.close()
if rWrapper != nil {
rWrapper.close()
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}
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if bWrapper != nil {
bWrapper.close()
}
for ac := range conns {
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ac.tearDown(ErrClientConnClosing)
}
return nil
}
// addrConn is a network connection to a given address.
type addrConn struct {
ctx context.Context
cancel context.CancelFunc
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cc *ClientConn
addrs []resolver.Address
dopts dialOptions
events trace.EventLog
acbw balancer.SubConn
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2018-01-03 19:19:49 +00:00
mu sync.Mutex
curAddr resolver.Address
reconnectIdx int // The index in addrs list to start reconnecting from.
state connectivity.State
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// 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
2018-01-03 19:19:49 +00:00
connectRetryNum int
// backoffDeadline is the time until which resetTransport needs to
// wait before increasing connectRetryNum count.
backoffDeadline time.Time
// connectDeadline is the time by which all connection
// negotiations must complete.
connectDeadline time.Time
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}
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// adjustParams updates parameters used to create transports upon
// receiving a GoAway.
func (ac *addrConn) adjustParams(r transport.GoAwayReason) {
switch r {
2018-01-03 19:19:49 +00:00
case transport.GoAwayTooManyPings:
2017-09-30 16:47:47 +00:00
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()
}
}
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// 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...)
}
}
2018-01-03 19:19:49 +00:00
// resetTransport recreates a transport to the address for ac. The old
// transport will close itself on error or when the clientconn is closed.
// The created transport must receive initial settings frame from the server.
// In case that doesnt happen, transportMonitor will kill the newly created
// transport after connectDeadline has expired.
// In case there was an error on the transport before the settings frame was
// received, resetTransport resumes connecting to backends after the one that
// was previously connected to. In case end of the list is reached, resetTransport
// backs off until the original deadline.
// If the DialOption WithWaitForHandshake was set, resetTrasport returns
// successfully only after server settings are received.
//
// TODO(bar) make sure all state transitions are valid.
func (ac *addrConn) resetTransport() error {
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ac.mu.Lock()
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if ac.state == connectivity.Shutdown {
ac.mu.Unlock()
return errConnClosing
2017-01-26 15:51:44 +00:00
}
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if ac.ready != nil {
close(ac.ready)
ac.ready = nil
2017-10-06 15:29:20 +00:00
}
2017-09-30 16:47:47 +00:00
ac.transport = nil
2018-01-03 19:19:49 +00:00
ridx := ac.reconnectIdx
2017-09-30 16:47:47 +00:00
ac.mu.Unlock()
ac.cc.mu.RLock()
ac.dopts.copts.KeepaliveParams = ac.cc.mkp
ac.cc.mu.RUnlock()
2018-01-03 19:19:49 +00:00
var backoffDeadline, connectDeadline time.Time
for connectRetryNum := 0; ; connectRetryNum++ {
2017-10-06 15:29:20 +00:00
ac.mu.Lock()
2018-01-03 19:19:49 +00:00
if ac.backoffDeadline.IsZero() {
// This means either a successful HTTP2 connection was established
// or this is the first time this addrConn is trying to establish a
// connection.
backoffFor := ac.dopts.bs.backoff(connectRetryNum) // time.Duration.
// This will be the duration that dial gets to finish.
dialDuration := minConnectTimeout
if backoffFor > dialDuration {
// Give dial more time as we keep failing to connect.
dialDuration = backoffFor
}
start := time.Now()
backoffDeadline = start.Add(backoffFor)
connectDeadline = start.Add(dialDuration)
ridx = 0 // Start connecting from the beginning.
} else {
// Continue trying to conect with the same deadlines.
connectRetryNum = ac.connectRetryNum
backoffDeadline = ac.backoffDeadline
connectDeadline = ac.connectDeadline
ac.backoffDeadline = time.Time{}
ac.connectDeadline = time.Time{}
ac.connectRetryNum = 0
}
if ac.state == connectivity.Shutdown {
ac.mu.Unlock()
return errConnClosing
}
ac.printf("connecting")
if ac.state != connectivity.Connecting {
ac.state = connectivity.Connecting
ac.cc.handleSubConnStateChange(ac.acbw, ac.state)
2017-09-30 16:47:47 +00:00
}
// copy ac.addrs in case of race
2018-01-03 19:19:49 +00:00
addrsIter := make([]resolver.Address, len(ac.addrs))
2017-09-30 16:47:47 +00:00
copy(addrsIter, ac.addrs)
2018-01-03 19:19:49 +00:00
copts := ac.dopts.copts
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ac.mu.Unlock()
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connected, err := ac.createTransport(connectRetryNum, ridx, backoffDeadline, connectDeadline, addrsIter, copts)
if err != nil {
return err
}
if connected {
return nil
}
}
}
// createTransport creates a connection to one of the backends in addrs.
// It returns true if a connection was established.
func (ac *addrConn) createTransport(connectRetryNum, ridx int, backoffDeadline, connectDeadline time.Time, addrs []resolver.Address, copts transport.ConnectOptions) (bool, error) {
for i := ridx; i < len(addrs); i++ {
addr := addrs[i]
target := transport.TargetInfo{
Addr: addr.Addr,
Metadata: addr.Metadata,
Authority: ac.cc.authority,
}
done := make(chan struct{})
onPrefaceReceipt := func() {
2017-09-30 16:47:47 +00:00
ac.mu.Lock()
2018-01-17 04:32:31 +00:00
close(done)
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if !ac.backoffDeadline.IsZero() {
// If we haven't already started reconnecting to
// other backends.
// Note, this can happen when writer notices an error
// and triggers resetTransport while at the same time
// reader receives the preface and invokes this closure.
ac.backoffDeadline = time.Time{}
ac.connectDeadline = time.Time{}
ac.connectRetryNum = 0
2017-09-30 16:47:47 +00:00
}
ac.mu.Unlock()
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}
// Do not cancel in the success path because of
// this issue in Go1.6: https://github.com/golang/go/issues/15078.
connectCtx, cancel := context.WithDeadline(ac.ctx, connectDeadline)
newTr, err := transport.NewClientTransport(connectCtx, ac.cc.ctx, target, copts, onPrefaceReceipt)
if err != nil {
cancel()
if e, ok := err.(transport.ConnectionError); ok && !e.Temporary() {
2017-09-30 16:47:47 +00:00
ac.mu.Lock()
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if ac.state != connectivity.Shutdown {
ac.state = connectivity.TransientFailure
ac.cc.handleSubConnStateChange(ac.acbw, ac.state)
2017-10-06 15:29:20 +00:00
}
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ac.mu.Unlock()
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return false, err
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}
ac.mu.Lock()
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if ac.state == connectivity.Shutdown {
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// ac.tearDown(...) has been invoked.
ac.mu.Unlock()
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return false, errConnClosing
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}
2018-01-03 19:19:49 +00:00
ac.mu.Unlock()
grpclog.Warningf("grpc: addrConn.createTransport failed to connect to %v. Err :%v. Reconnecting...", addr, err)
continue
}
if ac.dopts.waitForHandshake {
select {
case <-done:
case <-connectCtx.Done():
// Didn't receive server preface, must kill this new transport now.
grpclog.Warningf("grpc: addrConn.createTransport failed to receive server preface before deadline.")
newTr.Close()
break
case <-ac.ctx.Done():
2017-10-06 15:29:20 +00:00
}
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}
ac.mu.Lock()
if ac.state == connectivity.Shutdown {
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ac.mu.Unlock()
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// ac.tearDonn(...) has been invoked.
newTr.Close()
return false, errConnClosing
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}
2018-01-03 19:19:49 +00:00
ac.printf("ready")
ac.state = connectivity.Ready
ac.cc.handleSubConnStateChange(ac.acbw, ac.state)
ac.transport = newTr
ac.curAddr = addr
if ac.ready != nil {
close(ac.ready)
ac.ready = nil
2017-09-30 16:47:47 +00:00
}
2018-01-17 04:32:31 +00:00
select {
case <-done:
// If the server has responded back with preface already,
// don't set the reconnect parameters.
default:
ac.connectRetryNum = connectRetryNum
ac.backoffDeadline = backoffDeadline
ac.connectDeadline = connectDeadline
ac.reconnectIdx = i + 1 // Start reconnecting from the next backend in the list.
}
2018-01-03 19:19:49 +00:00
ac.mu.Unlock()
return true, nil
}
ac.mu.Lock()
ac.state = connectivity.TransientFailure
ac.cc.handleSubConnStateChange(ac.acbw, ac.state)
ac.cc.resolveNow(resolver.ResolveNowOption{})
if ac.ready != nil {
close(ac.ready)
ac.ready = nil
}
ac.mu.Unlock()
timer := time.NewTimer(backoffDeadline.Sub(time.Now()))
select {
case <-timer.C:
case <-ac.ctx.Done():
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timer.Stop()
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return false, ac.ctx.Err()
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}
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return false, nil
2017-01-26 15:51:44 +00:00
}
// 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 {
2018-01-03 19:19:49 +00:00
var timer *time.Timer
var cdeadline <-chan time.Time
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ac.mu.Lock()
t := ac.transport
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if !ac.connectDeadline.IsZero() {
timer = time.NewTimer(ac.connectDeadline.Sub(time.Now()))
cdeadline = timer.C
}
2017-01-26 15:51:44 +00:00
ac.mu.Unlock()
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// Block until we receive a goaway or an error occurs.
2017-01-26 15:51:44 +00:00
select {
case <-t.GoAway():
case <-t.Error():
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case <-cdeadline:
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ac.mu.Lock()
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// This implies that client received server preface.
if ac.backoffDeadline.IsZero() {
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ac.mu.Unlock()
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continue
2017-10-06 15:29:20 +00:00
}
ac.mu.Unlock()
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timer = nil
// No server preface received until deadline.
// Kill the connection.
grpclog.Warningf("grpc: addrConn.transportMonitor didn't get server preface after waiting. Closing the new transport now.")
t.Close()
}
if timer != nil {
timer.Stop()
}
// If a GoAway happened, regardless of error, adjust our keepalive
// parameters as appropriate.
select {
case <-t.GoAway():
ac.adjustParams(t.GetGoAwayReason())
default:
}
ac.mu.Lock()
if ac.state == connectivity.Shutdown {
ac.mu.Unlock()
return
}
// Set connectivity state to TransientFailure before calling
// resetTransport. Transition READY->CONNECTING is not valid.
ac.state = connectivity.TransientFailure
ac.cc.handleSubConnStateChange(ac.acbw, ac.state)
ac.cc.resolveNow(resolver.ResolveNowOption{})
ac.curAddr = resolver.Address{}
ac.mu.Unlock()
if err := ac.resetTransport(); err != nil {
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)
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}
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return
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}
}
}
// wait blocks until i) the new transport is up or ii) ctx is done or iii) ac is closed or
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// iv) transport is in connectivity.TransientFailure and there is a balancer/failfast is true.
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func (ac *addrConn) wait(ctx context.Context, hasBalancer, failfast bool) (transport.ClientTransport, error) {
for {
ac.mu.Lock()
switch {
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case ac.state == connectivity.Shutdown:
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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
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case ac.state == connectivity.Ready:
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ct := ac.transport
ac.mu.Unlock()
return ct, nil
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case ac.state == connectivity.TransientFailure:
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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:
}
}
}
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// getReadyTransport returns the transport if ac's state is READY.
// Otherwise it returns nil, false.
// If ac's state is IDLE, it will trigger ac to connect.
func (ac *addrConn) getReadyTransport() (transport.ClientTransport, bool) {
ac.mu.Lock()
if ac.state == connectivity.Ready {
t := ac.transport
ac.mu.Unlock()
return t, true
}
var idle bool
if ac.state == connectivity.Idle {
idle = true
}
ac.mu.Unlock()
// Trigger idle ac to connect.
if idle {
ac.connect()
}
return nil, false
}
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// 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()
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if ac.state == connectivity.Shutdown {
return
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}
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ac.curAddr = resolver.Address{}
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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()
}
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ac.state = connectivity.Shutdown
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ac.tearDownErr = err
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ac.cc.handleSubConnStateChange(ac.acbw, ac.state)
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if ac.events != nil {
ac.events.Finish()
ac.events = nil
}
if ac.ready != nil {
close(ac.ready)
ac.ready = nil
}
return
}
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func (ac *addrConn) getState() connectivity.State {
ac.mu.Lock()
defer ac.mu.Unlock()
return ac.state
}