140 lines
3.8 KiB
Go
140 lines
3.8 KiB
Go
/*
|
|
*
|
|
* Copyright 2017 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 (
|
|
"strings"
|
|
|
|
"google.golang.org/grpc/grpclog"
|
|
"google.golang.org/grpc/resolver"
|
|
)
|
|
|
|
// ccResolverWrapper is a wrapper on top of cc for resolvers.
|
|
// It implements resolver.ClientConnection interface.
|
|
type ccResolverWrapper struct {
|
|
cc *ClientConn
|
|
resolver resolver.Resolver
|
|
addrCh chan []resolver.Address
|
|
scCh chan string
|
|
done chan struct{}
|
|
}
|
|
|
|
// split2 returns the values from strings.SplitN(s, sep, 2).
|
|
// If sep is not found, it returns "", s instead.
|
|
func split2(s, sep string) (string, string) {
|
|
spl := strings.SplitN(s, sep, 2)
|
|
if len(spl) < 2 {
|
|
return "", s
|
|
}
|
|
return spl[0], spl[1]
|
|
}
|
|
|
|
// parseTarget splits target into a struct containing scheme, authority and
|
|
// endpoint.
|
|
func parseTarget(target string) (ret resolver.Target) {
|
|
ret.Scheme, ret.Endpoint = split2(target, "://")
|
|
ret.Authority, ret.Endpoint = split2(ret.Endpoint, "/")
|
|
return ret
|
|
}
|
|
|
|
// newCCResolverWrapper parses cc.target for scheme and gets the resolver
|
|
// builder for this scheme. It then builds the resolver and starts the
|
|
// monitoring goroutine for it.
|
|
//
|
|
// This function could return nil, nil, in tests for old behaviors.
|
|
// TODO(bar) never return nil, nil when DNS becomes the default resolver.
|
|
func newCCResolverWrapper(cc *ClientConn) (*ccResolverWrapper, error) {
|
|
target := parseTarget(cc.target)
|
|
grpclog.Infof("dialing to target with scheme: %q", target.Scheme)
|
|
|
|
rb := resolver.Get(target.Scheme)
|
|
if rb == nil {
|
|
// TODO(bar) return error when DNS becomes the default (implemented and
|
|
// registered by DNS package).
|
|
grpclog.Infof("could not get resolver for scheme: %q", target.Scheme)
|
|
return nil, nil
|
|
}
|
|
|
|
ccr := &ccResolverWrapper{
|
|
cc: cc,
|
|
addrCh: make(chan []resolver.Address, 1),
|
|
scCh: make(chan string, 1),
|
|
done: make(chan struct{}),
|
|
}
|
|
|
|
var err error
|
|
ccr.resolver, err = rb.Build(target, ccr, resolver.BuildOption{})
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
go ccr.watcher()
|
|
return ccr, nil
|
|
}
|
|
|
|
// watcher processes address updates and service config updates sequencially.
|
|
// Otherwise, we need to resolve possible races between address and service
|
|
// config (e.g. they specify different balancer types).
|
|
func (ccr *ccResolverWrapper) watcher() {
|
|
for {
|
|
select {
|
|
case <-ccr.done:
|
|
return
|
|
default:
|
|
}
|
|
|
|
select {
|
|
case addrs := <-ccr.addrCh:
|
|
grpclog.Infof("ccResolverWrapper: sending new addresses to balancer wrapper: %v", addrs)
|
|
// TODO(bar switching) this should never be nil. Pickfirst should be default.
|
|
if ccr.cc.balancerWrapper != nil {
|
|
// TODO(bar switching) create balancer if it's nil?
|
|
ccr.cc.balancerWrapper.handleResolvedAddrs(addrs, nil)
|
|
}
|
|
case sc := <-ccr.scCh:
|
|
grpclog.Infof("ccResolverWrapper: got new service config: %v", sc)
|
|
case <-ccr.done:
|
|
return
|
|
}
|
|
}
|
|
}
|
|
|
|
func (ccr *ccResolverWrapper) close() {
|
|
ccr.resolver.Close()
|
|
close(ccr.done)
|
|
}
|
|
|
|
// NewAddress is called by the resolver implemenetion to send addresses to gRPC.
|
|
func (ccr *ccResolverWrapper) NewAddress(addrs []resolver.Address) {
|
|
select {
|
|
case <-ccr.addrCh:
|
|
default:
|
|
}
|
|
ccr.addrCh <- addrs
|
|
}
|
|
|
|
// NewServiceConfig is called by the resolver implemenetion to send service
|
|
// configs to gPRC.
|
|
func (ccr *ccResolverWrapper) NewServiceConfig(sc string) {
|
|
select {
|
|
case <-ccr.scCh:
|
|
default:
|
|
}
|
|
ccr.scCh <- sc
|
|
}
|