initial add - go fmt on grpc
Change-Id: Ib0afadd2fe5571d1456a091f94f5644458f7d3f4
diff --git a/vendor/google.golang.org/grpc/balancer.go b/vendor/google.golang.org/grpc/balancer.go
new file mode 100644
index 0000000..a8eb0f4
--- /dev/null
+++ b/vendor/google.golang.org/grpc/balancer.go
@@ -0,0 +1,391 @@
+/*
+ *
+ * Copyright 2016 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"
+ "net"
+ "sync"
+
+ "google.golang.org/grpc/codes"
+ "google.golang.org/grpc/credentials"
+ "google.golang.org/grpc/grpclog"
+ "google.golang.org/grpc/naming"
+ "google.golang.org/grpc/status"
+)
+
+// Address represents a server the client connects to.
+//
+// Deprecated: please use package balancer.
+type Address struct {
+ // Addr is the server address on which a connection will be established.
+ Addr string
+ // Metadata is the information associated with Addr, which may be used
+ // to make load balancing decision.
+ Metadata interface{}
+}
+
+// BalancerConfig specifies the configurations for Balancer.
+//
+// Deprecated: please use package balancer. May be removed in a future 1.x release.
+type BalancerConfig struct {
+ // DialCreds is the transport credential the Balancer implementation can
+ // use to dial to a remote load balancer server. The Balancer implementations
+ // can ignore this if it does not need to talk to another party securely.
+ DialCreds credentials.TransportCredentials
+ // Dialer is the custom dialer the Balancer implementation can use to dial
+ // to a remote load balancer server. The Balancer implementations
+ // can ignore this if it doesn't need to talk to remote balancer.
+ Dialer func(context.Context, string) (net.Conn, error)
+}
+
+// BalancerGetOptions configures a Get call.
+//
+// Deprecated: please use package balancer. May be removed in a future 1.x release.
+type BalancerGetOptions struct {
+ // BlockingWait specifies whether Get should block when there is no
+ // connected address.
+ BlockingWait bool
+}
+
+// Balancer chooses network addresses for RPCs.
+//
+// Deprecated: please use package balancer. May be removed in a future 1.x release.
+type Balancer interface {
+ // Start does the initialization work to bootstrap a Balancer. For example,
+ // this function may start the name resolution and watch the updates. It will
+ // be called when dialing.
+ Start(target string, config BalancerConfig) error
+ // Up informs the Balancer that gRPC has a connection to the server at
+ // addr. It returns down which is called once the connection to addr gets
+ // lost or closed.
+ // TODO: It is not clear how to construct and take advantage of the meaningful error
+ // parameter for down. Need realistic demands to guide.
+ Up(addr Address) (down func(error))
+ // Get gets the address of a server for the RPC corresponding to ctx.
+ // i) If it returns a connected address, gRPC internals issues the RPC on the
+ // connection to this address;
+ // ii) If it returns an address on which the connection is under construction
+ // (initiated by Notify(...)) but not connected, gRPC internals
+ // * fails RPC if the RPC is fail-fast and connection is in the TransientFailure or
+ // Shutdown state;
+ // or
+ // * issues RPC on the connection otherwise.
+ // iii) If it returns an address on which the connection does not exist, gRPC
+ // internals treats it as an error and will fail the corresponding RPC.
+ //
+ // Therefore, the following is the recommended rule when writing a custom Balancer.
+ // If opts.BlockingWait is true, it should return a connected address or
+ // block if there is no connected address. It should respect the timeout or
+ // cancellation of ctx when blocking. If opts.BlockingWait is false (for fail-fast
+ // RPCs), it should return an address it has notified via Notify(...) immediately
+ // instead of blocking.
+ //
+ // The function returns put which is called once the rpc has completed or failed.
+ // put can collect and report RPC stats to a remote load balancer.
+ //
+ // This function should only return the errors Balancer cannot recover by itself.
+ // gRPC internals will fail the RPC if an error is returned.
+ Get(ctx context.Context, opts BalancerGetOptions) (addr Address, put func(), err error)
+ // Notify returns a channel that is used by gRPC internals to watch the addresses
+ // gRPC needs to connect. The addresses might be from a name resolver or remote
+ // load balancer. gRPC internals will compare it with the existing connected
+ // addresses. If the address Balancer notified is not in the existing connected
+ // addresses, gRPC starts to connect the address. If an address in the existing
+ // connected addresses is not in the notification list, the corresponding connection
+ // is shutdown gracefully. Otherwise, there are no operations to take. Note that
+ // the Address slice must be the full list of the Addresses which should be connected.
+ // It is NOT delta.
+ Notify() <-chan []Address
+ // Close shuts down the balancer.
+ Close() error
+}
+
+// RoundRobin returns a Balancer that selects addresses round-robin. It uses r to watch
+// the name resolution updates and updates the addresses available correspondingly.
+//
+// Deprecated: please use package balancer/roundrobin. May be removed in a future 1.x release.
+func RoundRobin(r naming.Resolver) Balancer {
+ return &roundRobin{r: r}
+}
+
+type addrInfo struct {
+ addr Address
+ connected bool
+}
+
+type roundRobin struct {
+ r naming.Resolver
+ w naming.Watcher
+ addrs []*addrInfo // all the addresses the client should potentially connect
+ mu sync.Mutex
+ addrCh chan []Address // the channel to notify gRPC internals the list of addresses the client should connect to.
+ next int // index of the next address to return for Get()
+ waitCh chan struct{} // the channel to block when there is no connected address available
+ done bool // The Balancer is closed.
+}
+
+func (rr *roundRobin) watchAddrUpdates() error {
+ updates, err := rr.w.Next()
+ if err != nil {
+ grpclog.Warningf("grpc: the naming watcher stops working due to %v.", err)
+ return err
+ }
+ rr.mu.Lock()
+ defer rr.mu.Unlock()
+ for _, update := range updates {
+ addr := Address{
+ Addr: update.Addr,
+ Metadata: update.Metadata,
+ }
+ switch update.Op {
+ case naming.Add:
+ var exist bool
+ for _, v := range rr.addrs {
+ if addr == v.addr {
+ exist = true
+ grpclog.Infoln("grpc: The name resolver wanted to add an existing address: ", addr)
+ break
+ }
+ }
+ if exist {
+ continue
+ }
+ rr.addrs = append(rr.addrs, &addrInfo{addr: addr})
+ case naming.Delete:
+ for i, v := range rr.addrs {
+ if addr == v.addr {
+ copy(rr.addrs[i:], rr.addrs[i+1:])
+ rr.addrs = rr.addrs[:len(rr.addrs)-1]
+ break
+ }
+ }
+ default:
+ grpclog.Errorln("Unknown update.Op ", update.Op)
+ }
+ }
+ // Make a copy of rr.addrs and write it onto rr.addrCh so that gRPC internals gets notified.
+ open := make([]Address, len(rr.addrs))
+ for i, v := range rr.addrs {
+ open[i] = v.addr
+ }
+ if rr.done {
+ return ErrClientConnClosing
+ }
+ select {
+ case <-rr.addrCh:
+ default:
+ }
+ rr.addrCh <- open
+ return nil
+}
+
+func (rr *roundRobin) Start(target string, config BalancerConfig) error {
+ rr.mu.Lock()
+ defer rr.mu.Unlock()
+ if rr.done {
+ return ErrClientConnClosing
+ }
+ if rr.r == nil {
+ // If there is no name resolver installed, it is not needed to
+ // do name resolution. In this case, target is added into rr.addrs
+ // as the only address available and rr.addrCh stays nil.
+ rr.addrs = append(rr.addrs, &addrInfo{addr: Address{Addr: target}})
+ return nil
+ }
+ w, err := rr.r.Resolve(target)
+ if err != nil {
+ return err
+ }
+ rr.w = w
+ rr.addrCh = make(chan []Address, 1)
+ go func() {
+ for {
+ if err := rr.watchAddrUpdates(); err != nil {
+ return
+ }
+ }
+ }()
+ return nil
+}
+
+// Up sets the connected state of addr and sends notification if there are pending
+// Get() calls.
+func (rr *roundRobin) Up(addr Address) func(error) {
+ rr.mu.Lock()
+ defer rr.mu.Unlock()
+ var cnt int
+ for _, a := range rr.addrs {
+ if a.addr == addr {
+ if a.connected {
+ return nil
+ }
+ a.connected = true
+ }
+ if a.connected {
+ cnt++
+ }
+ }
+ // addr is only one which is connected. Notify the Get() callers who are blocking.
+ if cnt == 1 && rr.waitCh != nil {
+ close(rr.waitCh)
+ rr.waitCh = nil
+ }
+ return func(err error) {
+ rr.down(addr, err)
+ }
+}
+
+// down unsets the connected state of addr.
+func (rr *roundRobin) down(addr Address, err error) {
+ rr.mu.Lock()
+ defer rr.mu.Unlock()
+ for _, a := range rr.addrs {
+ if addr == a.addr {
+ a.connected = false
+ break
+ }
+ }
+}
+
+// Get returns the next addr in the rotation.
+func (rr *roundRobin) Get(ctx context.Context, opts BalancerGetOptions) (addr Address, put func(), err error) {
+ var ch chan struct{}
+ rr.mu.Lock()
+ if rr.done {
+ rr.mu.Unlock()
+ err = ErrClientConnClosing
+ return
+ }
+
+ if len(rr.addrs) > 0 {
+ if rr.next >= len(rr.addrs) {
+ rr.next = 0
+ }
+ next := rr.next
+ for {
+ a := rr.addrs[next]
+ next = (next + 1) % len(rr.addrs)
+ if a.connected {
+ addr = a.addr
+ rr.next = next
+ rr.mu.Unlock()
+ return
+ }
+ if next == rr.next {
+ // Has iterated all the possible address but none is connected.
+ break
+ }
+ }
+ }
+ if !opts.BlockingWait {
+ if len(rr.addrs) == 0 {
+ rr.mu.Unlock()
+ err = status.Errorf(codes.Unavailable, "there is no address available")
+ return
+ }
+ // Returns the next addr on rr.addrs for failfast RPCs.
+ addr = rr.addrs[rr.next].addr
+ rr.next++
+ rr.mu.Unlock()
+ return
+ }
+ // Wait on rr.waitCh for non-failfast RPCs.
+ if rr.waitCh == nil {
+ ch = make(chan struct{})
+ rr.waitCh = ch
+ } else {
+ ch = rr.waitCh
+ }
+ rr.mu.Unlock()
+ for {
+ select {
+ case <-ctx.Done():
+ err = ctx.Err()
+ return
+ case <-ch:
+ rr.mu.Lock()
+ if rr.done {
+ rr.mu.Unlock()
+ err = ErrClientConnClosing
+ return
+ }
+
+ if len(rr.addrs) > 0 {
+ if rr.next >= len(rr.addrs) {
+ rr.next = 0
+ }
+ next := rr.next
+ for {
+ a := rr.addrs[next]
+ next = (next + 1) % len(rr.addrs)
+ if a.connected {
+ addr = a.addr
+ rr.next = next
+ rr.mu.Unlock()
+ return
+ }
+ if next == rr.next {
+ // Has iterated all the possible address but none is connected.
+ break
+ }
+ }
+ }
+ // The newly added addr got removed by Down() again.
+ if rr.waitCh == nil {
+ ch = make(chan struct{})
+ rr.waitCh = ch
+ } else {
+ ch = rr.waitCh
+ }
+ rr.mu.Unlock()
+ }
+ }
+}
+
+func (rr *roundRobin) Notify() <-chan []Address {
+ return rr.addrCh
+}
+
+func (rr *roundRobin) Close() error {
+ rr.mu.Lock()
+ defer rr.mu.Unlock()
+ if rr.done {
+ return errBalancerClosed
+ }
+ rr.done = true
+ if rr.w != nil {
+ rr.w.Close()
+ }
+ if rr.waitCh != nil {
+ close(rr.waitCh)
+ rr.waitCh = nil
+ }
+ if rr.addrCh != nil {
+ close(rr.addrCh)
+ }
+ return nil
+}
+
+// pickFirst is used to test multi-addresses in one addrConn in which all addresses share the same addrConn.
+// It is a wrapper around roundRobin balancer. The logic of all methods works fine because balancer.Get()
+// returns the only address Up by resetTransport().
+type pickFirst struct {
+ *roundRobin
+}