--- /dev/null
+/*
+ *
+ * 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 (
+ "fmt"
+ "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, false) instead.
+func split2(s, sep string) (string, string, bool) {
+ spl := strings.SplitN(s, sep, 2)
+ if len(spl) < 2 {
+ return "", "", false
+ }
+ return spl[0], spl[1], true
+}
+
+// parseTarget splits target into a struct containing scheme, authority and
+// endpoint.
+func parseTarget(target string) (ret resolver.Target) {
+ var ok bool
+ ret.Scheme, ret.Endpoint, ok = split2(target, "://")
+ if !ok {
+ return resolver.Target{Endpoint: 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.
+func newCCResolverWrapper(cc *ClientConn) (*ccResolverWrapper, error) {
+ grpclog.Infof("dialing to target with scheme: %q", cc.parsedTarget.Scheme)
+
+ rb := resolver.Get(cc.parsedTarget.Scheme)
+ if rb == nil {
+ return nil, fmt.Errorf("could not get resolver for scheme: %q", cc.parsedTarget.Scheme)
+ }
+
+ 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(cc.parsedTarget, 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:
+ select {
+ case <-ccr.done:
+ return
+ default:
+ }
+ grpclog.Infof("ccResolverWrapper: sending new addresses to cc: %v", addrs)
+ ccr.cc.handleResolvedAddrs(addrs, nil)
+ case sc := <-ccr.scCh:
+ select {
+ case <-ccr.done:
+ return
+ default:
+ }
+ grpclog.Infof("ccResolverWrapper: got new service config: %v", sc)
+ ccr.cc.handleServiceConfig(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
+}
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