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Diffstat (limited to 'vendor/google.golang.org/grpc/balancer.go')
| -rw-r--r-- | vendor/google.golang.org/grpc/balancer.go | 400 |
1 files changed, 0 insertions, 400 deletions
diff --git a/vendor/google.golang.org/grpc/balancer.go b/vendor/google.golang.org/grpc/balancer.go deleted file mode 100644 index 9d943fbad..000000000 --- a/vendor/google.golang.org/grpc/balancer.go +++ /dev/null @@ -1,400 +0,0 @@ -/* - * - * Copyright 2016, Google Inc. - * All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions are - * met: - * - * * Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * * Redistributions in binary form must reproduce the above - * copyright notice, this list of conditions and the following disclaimer - * in the documentation and/or other materials provided with the - * distribution. - * * Neither the name of Google Inc. nor the names of its - * contributors may be used to endorse or promote products derived from - * this software without specific prior written permission. - * - * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS - * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT - * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR - * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT - * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, - * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT - * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, - * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY - * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT - * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE - * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. - * - */ - -package grpc - -import ( - "fmt" - "sync" - - "golang.org/x/net/context" - "google.golang.org/grpc/codes" - "google.golang.org/grpc/credentials" - "google.golang.org/grpc/grpclog" - "google.golang.org/grpc/naming" -) - -// Address represents a server the client connects to. -// This is the EXPERIMENTAL API and may be changed or extended in the future. -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. -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 -} - -// BalancerGetOptions configures a Get call. -// This is the EXPERIMENTAL API and may be changed or extended in the future. -type BalancerGetOptions struct { - // BlockingWait specifies whether Get should block when there is no - // connected address. - BlockingWait bool -} - -// Balancer chooses network addresses for RPCs. -// This is the EXPERIMENTAL API and may be changed or extended in the future. -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 -} - -// downErr implements net.Error. It is constructed by gRPC internals and passed to the down -// call of Balancer. -type downErr struct { - timeout bool - temporary bool - desc string -} - -func (e downErr) Error() string { return e.desc } -func (e downErr) Timeout() bool { return e.timeout } -func (e downErr) Temporary() bool { return e.temporary } - -func downErrorf(timeout, temporary bool, format string, a ...interface{}) downErr { - return downErr{ - timeout: timeout, - temporary: temporary, - desc: fmt.Sprintf(format, a...), - } -} - -// RoundRobin returns a Balancer that selects addresses round-robin. It uses r to watch -// the name resolution updates and updates the addresses available correspondingly. -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.Printf("grpc: the naming watcher stops working due to %v.\n", 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.Println("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.Println("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 - } - 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) - 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 = 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() - 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 -} |