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/*
*
* Copyright 2018 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 (
"context"
"fmt"
"net"
"time"
"google.golang.org/grpc/balancer"
"google.golang.org/grpc/credentials"
"google.golang.org/grpc/internal"
"google.golang.org/grpc/internal/backoff"
"google.golang.org/grpc/internal/envconfig"
"google.golang.org/grpc/internal/transport"
"google.golang.org/grpc/keepalive"
"google.golang.org/grpc/resolver"
"google.golang.org/grpc/stats"
)
// dialOptions configure a Dial call. dialOptions are set by the DialOption
// values passed to Dial.
type dialOptions struct {
unaryInt UnaryClientInterceptor
streamInt StreamClientInterceptor
cp Compressor
dc Decompressor
bs backoff.Strategy
block bool
insecure bool
timeout time.Duration
scChan <-chan ServiceConfig
authority string
copts transport.ConnectOptions
callOptions []CallOption
// 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
reqHandshake envconfig.RequireHandshakeSetting
channelzParentID int64
disableServiceConfig bool
disableRetry bool
disableHealthCheck bool
healthCheckFunc internal.HealthChecker
}
// DialOption configures how we set up the connection.
type DialOption interface {
apply(*dialOptions)
}
// EmptyDialOption does not alter the dial configuration. It can be embedded in
// another structure to build custom dial options.
//
// This API is EXPERIMENTAL.
type EmptyDialOption struct{}
func (EmptyDialOption) apply(*dialOptions) {}
// funcDialOption wraps a function that modifies dialOptions into an
// implementation of the DialOption interface.
type funcDialOption struct {
f func(*dialOptions)
}
func (fdo *funcDialOption) apply(do *dialOptions) {
fdo.f(do)
}
func newFuncDialOption(f func(*dialOptions)) *funcDialOption {
return &funcDialOption{
f: f,
}
}
// WithWaitForHandshake blocks until the initial settings frame is received from
// the server before assigning RPCs to the connection.
//
// Deprecated: this will become the default behavior in the 1.18 release, and
// will be removed after the 1.18 release. To override the default behavior in
// the 1.18 release, either use this dial option or set the environment
// variable GRPC_GO_READY_BEFORE_HANDSHAKE=on.
func WithWaitForHandshake() DialOption {
return newFuncDialOption(func(o *dialOptions) {
o.reqHandshake = envconfig.RequireHandshakeOn
})
}
// WithWriteBufferSize determines how much data can be batched before doing a
// write on the wire. The corresponding memory allocation for this buffer will
// be twice the size to keep syscalls low. The default value for this buffer is
// 32KB.
//
// Zero will disable the write buffer such that each write will be on underlying
// connection. Note: A Send call may not directly translate to a write.
func WithWriteBufferSize(s int) DialOption {
return newFuncDialOption(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.
//
// The default value for this buffer is 32KB. Zero will disable read buffer for
// a connection so data framer can access the underlying conn directly.
func WithReadBufferSize(s int) DialOption {
return newFuncDialOption(func(o *dialOptions) {
o.copts.ReadBufferSize = s
})
}
// 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 newFuncDialOption(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 newFuncDialOption(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 newFuncDialOption(func(o *dialOptions) {
o.callOptions = append(o.callOptions, cos...)
})
}
// WithCodec returns a DialOption which sets a codec for message marshaling and
// unmarshaling.
//
// Deprecated: use WithDefaultCallOptions(CallCustomCodec(c)) instead.
func WithCodec(c Codec) DialOption {
return WithDefaultCallOptions(CallCustomCodec(c))
}
// 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.
func WithCompressor(cp Compressor) DialOption {
return newFuncDialOption(func(o *dialOptions) {
o.cp = cp
})
}
// 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.
func WithDecompressor(dc Decompressor) DialOption {
return newFuncDialOption(func(o *dialOptions) {
o.dc = dc
})
}
// 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.
func WithBalancer(b Balancer) DialOption {
return newFuncDialOption(func(o *dialOptions) {
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 newFuncDialOption(func(o *dialOptions) {
o.balancerBuilder = builder
})
}
// withResolverBuilder is only for grpclb.
func withResolverBuilder(b resolver.Builder) DialOption {
return newFuncDialOption(func(o *dialOptions) {
o.resolverBuilder = b
})
}
// WithServiceConfig returns a DialOption which has a channel to read the
// service configuration.
//
// Deprecated: service config should be received through name resolver, as
// specified here.
// https://github.com/grpc/grpc/blob/master/doc/service_config.md
func WithServiceConfig(c <-chan ServiceConfig) DialOption {
return newFuncDialOption(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 {
return withBackoff(backoff.Exponential{
MaxDelay: b.MaxDelay,
})
}
// withBackoff sets the backoff strategy used for connectRetryNum after a failed
// connection attempt.
//
// This can be exported if arbitrary backoff strategies are allowed by gRPC.
func withBackoff(bs backoff.Strategy) DialOption {
return newFuncDialOption(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 newFuncDialOption(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 newFuncDialOption(func(o *dialOptions) {
o.insecure = true
})
}
// WithTransportCredentials returns a DialOption which configures a connection
// level security credentials (e.g., TLS/SSL). This should not be used together
// with WithCredentialsBundle.
func WithTransportCredentials(creds credentials.TransportCredentials) DialOption {
return newFuncDialOption(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 newFuncDialOption(func(o *dialOptions) {
o.copts.PerRPCCredentials = append(o.copts.PerRPCCredentials, creds)
})
}
// WithCredentialsBundle returns a DialOption to set a credentials bundle for
// the ClientConn.WithCreds. This should not be used together with
// WithTransportCredentials.
//
// This API is experimental.
func WithCredentialsBundle(b credentials.Bundle) DialOption {
return newFuncDialOption(func(o *dialOptions) {
o.copts.CredsBundle = b
})
}
// 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 newFuncDialOption(func(o *dialOptions) {
o.timeout = d
})
}
func withContextDialer(f func(context.Context, string) (net.Conn, error)) DialOption {
return newFuncDialOption(func(o *dialOptions) {
o.copts.Dialer = f
})
}
func init() {
internal.WithContextDialer = withContextDialer
internal.WithResolverBuilder = withResolverBuilder
internal.WithHealthCheckFunc = withHealthCheckFunc
}
// 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 withContextDialer(
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 newFuncDialOption(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.
//
// FailOnNonTempDialError only affects the initial dial, and does not do
// anything useful unless you are also using WithBlock().
//
// This is an EXPERIMENTAL API.
func FailOnNonTempDialError(f bool) DialOption {
return newFuncDialOption(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 newFuncDialOption(func(o *dialOptions) {
o.copts.UserAgent = s
})
}
// WithKeepaliveParams returns a DialOption that specifies keepalive parameters
// for the client transport.
func WithKeepaliveParams(kp keepalive.ClientParameters) DialOption {
return newFuncDialOption(func(o *dialOptions) {
o.copts.KeepaliveParams = kp
})
}
// WithUnaryInterceptor returns a DialOption that specifies the interceptor for
// unary RPCs.
func WithUnaryInterceptor(f UnaryClientInterceptor) DialOption {
return newFuncDialOption(func(o *dialOptions) {
o.unaryInt = f
})
}
// WithStreamInterceptor returns a DialOption that specifies the interceptor for
// streaming RPCs.
func WithStreamInterceptor(f StreamClientInterceptor) DialOption {
return newFuncDialOption(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 newFuncDialOption(func(o *dialOptions) {
o.authority = a
})
}
// WithChannelzParentID returns a DialOption that specifies the channelz ID of
// current ClientConn's parent. This function is used in nested channel creation
// (e.g. grpclb dial).
func WithChannelzParentID(id int64) DialOption {
return newFuncDialOption(func(o *dialOptions) {
o.channelzParentID = id
})
}
// WithDisableServiceConfig returns a DialOption that causes grpc to ignore any
// service config provided by the resolver and provides a hint to the resolver
// to not fetch service configs.
func WithDisableServiceConfig() DialOption {
return newFuncDialOption(func(o *dialOptions) {
o.disableServiceConfig = true
})
}
// WithDisableRetry returns a DialOption that disables retries, even if the
// service config enables them. This does not impact transparent retries, which
// will happen automatically if no data is written to the wire or if the RPC is
// unprocessed by the remote server.
//
// Retry support is currently disabled by default, but will be enabled by
// default in the future. Until then, it may be enabled by setting the
// environment variable "GRPC_GO_RETRY" to "on".
//
// This API is EXPERIMENTAL.
func WithDisableRetry() DialOption {
return newFuncDialOption(func(o *dialOptions) {
o.disableRetry = true
})
}
// WithMaxHeaderListSize returns a DialOption that specifies the maximum
// (uncompressed) size of header list that the client is prepared to accept.
func WithMaxHeaderListSize(s uint32) DialOption {
return newFuncDialOption(func(o *dialOptions) {
o.copts.MaxHeaderListSize = &s
})
}
// WithDisableHealthCheck disables the LB channel health checking for all SubConns of this ClientConn.
//
// This API is EXPERIMENTAL.
func WithDisableHealthCheck() DialOption {
return newFuncDialOption(func(o *dialOptions) {
o.disableHealthCheck = true
})
}
// withHealthCheckFunc replaces the default health check function with the provided one. It makes
// tests easier to change the health check function.
//
// For testing purpose only.
func withHealthCheckFunc(f internal.HealthChecker) DialOption {
return newFuncDialOption(func(o *dialOptions) {
o.healthCheckFunc = f
})
}
func defaultDialOptions() dialOptions {
return dialOptions{
disableRetry: !envconfig.Retry,
reqHandshake: envconfig.RequireHandshake,
healthCheckFunc: internal.HealthCheckFunc,
copts: transport.ConnectOptions{
WriteBufferSize: defaultWriteBufSize,
ReadBufferSize: defaultReadBufSize,
},
}
}