diff options
Diffstat (limited to 'vendor/gopkg.in/mgo.v2/cluster.go')
| -rw-r--r-- | vendor/gopkg.in/mgo.v2/cluster.go | 679 |
1 files changed, 679 insertions, 0 deletions
diff --git a/vendor/gopkg.in/mgo.v2/cluster.go b/vendor/gopkg.in/mgo.v2/cluster.go new file mode 100644 index 0000000..e28af5b --- /dev/null +++ b/vendor/gopkg.in/mgo.v2/cluster.go @@ -0,0 +1,679 @@ +// mgo - MongoDB driver for Go +// +// Copyright (c) 2010-2012 - Gustavo Niemeyer <gustavo@niemeyer.net> +// +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are met: +// +// 1. Redistributions of source code must retain the above copyright notice, this +// list of conditions and the following disclaimer. +// 2. 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. +// +// 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 mgo + +import ( + "errors" + "fmt" + "net" + "strconv" + "strings" + "sync" + "time" + + "gopkg.in/mgo.v2/bson" +) + +// --------------------------------------------------------------------------- +// Mongo cluster encapsulation. +// +// A cluster enables the communication with one or more servers participating +// in a mongo cluster. This works with individual servers, a replica set, +// a replica pair, one or multiple mongos routers, etc. + +type mongoCluster struct { + sync.RWMutex + serverSynced sync.Cond + userSeeds []string + dynaSeeds []string + servers mongoServers + masters mongoServers + references int + syncing bool + direct bool + failFast bool + syncCount uint + setName string + cachedIndex map[string]bool + sync chan bool + dial dialer +} + +func newCluster(userSeeds []string, direct, failFast bool, dial dialer, setName string) *mongoCluster { + cluster := &mongoCluster{ + userSeeds: userSeeds, + references: 1, + direct: direct, + failFast: failFast, + dial: dial, + setName: setName, + } + cluster.serverSynced.L = cluster.RWMutex.RLocker() + cluster.sync = make(chan bool, 1) + stats.cluster(+1) + go cluster.syncServersLoop() + return cluster +} + +// Acquire increases the reference count for the cluster. +func (cluster *mongoCluster) Acquire() { + cluster.Lock() + cluster.references++ + debugf("Cluster %p acquired (refs=%d)", cluster, cluster.references) + cluster.Unlock() +} + +// Release decreases the reference count for the cluster. Once +// it reaches zero, all servers will be closed. +func (cluster *mongoCluster) Release() { + cluster.Lock() + if cluster.references == 0 { + panic("cluster.Release() with references == 0") + } + cluster.references-- + debugf("Cluster %p released (refs=%d)", cluster, cluster.references) + if cluster.references == 0 { + for _, server := range cluster.servers.Slice() { + server.Close() + } + // Wake up the sync loop so it can die. + cluster.syncServers() + stats.cluster(-1) + } + cluster.Unlock() +} + +func (cluster *mongoCluster) LiveServers() (servers []string) { + cluster.RLock() + for _, serv := range cluster.servers.Slice() { + servers = append(servers, serv.Addr) + } + cluster.RUnlock() + return servers +} + +func (cluster *mongoCluster) removeServer(server *mongoServer) { + cluster.Lock() + cluster.masters.Remove(server) + other := cluster.servers.Remove(server) + cluster.Unlock() + if other != nil { + other.Close() + log("Removed server ", server.Addr, " from cluster.") + } + server.Close() +} + +type isMasterResult struct { + IsMaster bool + Secondary bool + Primary string + Hosts []string + Passives []string + Tags bson.D + Msg string + SetName string `bson:"setName"` + MaxWireVersion int `bson:"maxWireVersion"` +} + +func (cluster *mongoCluster) isMaster(socket *mongoSocket, result *isMasterResult) error { + // Monotonic let's it talk to a slave and still hold the socket. + session := newSession(Monotonic, cluster, 10*time.Second) + session.setSocket(socket) + err := session.Run("ismaster", result) + session.Close() + return err +} + +type possibleTimeout interface { + Timeout() bool +} + +var syncSocketTimeout = 5 * time.Second + +func (cluster *mongoCluster) syncServer(server *mongoServer) (info *mongoServerInfo, hosts []string, err error) { + var syncTimeout time.Duration + if raceDetector { + // This variable is only ever touched by tests. + globalMutex.Lock() + syncTimeout = syncSocketTimeout + globalMutex.Unlock() + } else { + syncTimeout = syncSocketTimeout + } + + addr := server.Addr + log("SYNC Processing ", addr, "...") + + // Retry a few times to avoid knocking a server down for a hiccup. + var result isMasterResult + var tryerr error + for retry := 0; ; retry++ { + if retry == 3 || retry == 1 && cluster.failFast { + return nil, nil, tryerr + } + if retry > 0 { + // Don't abuse the server needlessly if there's something actually wrong. + if err, ok := tryerr.(possibleTimeout); ok && err.Timeout() { + // Give a chance for waiters to timeout as well. + cluster.serverSynced.Broadcast() + } + time.Sleep(syncShortDelay) + } + + // It's not clear what would be a good timeout here. Is it + // better to wait longer or to retry? + socket, _, err := server.AcquireSocket(0, syncTimeout) + if err != nil { + tryerr = err + logf("SYNC Failed to get socket to %s: %v", addr, err) + continue + } + err = cluster.isMaster(socket, &result) + socket.Release() + if err != nil { + tryerr = err + logf("SYNC Command 'ismaster' to %s failed: %v", addr, err) + continue + } + debugf("SYNC Result of 'ismaster' from %s: %#v", addr, result) + break + } + + if cluster.setName != "" && result.SetName != cluster.setName { + logf("SYNC Server %s is not a member of replica set %q", addr, cluster.setName) + return nil, nil, fmt.Errorf("server %s is not a member of replica set %q", addr, cluster.setName) + } + + if result.IsMaster { + debugf("SYNC %s is a master.", addr) + if !server.info.Master { + // Made an incorrect assumption above, so fix stats. + stats.conn(-1, false) + stats.conn(+1, true) + } + } else if result.Secondary { + debugf("SYNC %s is a slave.", addr) + } else if cluster.direct { + logf("SYNC %s in unknown state. Pretending it's a slave due to direct connection.", addr) + } else { + logf("SYNC %s is neither a master nor a slave.", addr) + // Let stats track it as whatever was known before. + return nil, nil, errors.New(addr + " is not a master nor slave") + } + + info = &mongoServerInfo{ + Master: result.IsMaster, + Mongos: result.Msg == "isdbgrid", + Tags: result.Tags, + SetName: result.SetName, + MaxWireVersion: result.MaxWireVersion, + } + + hosts = make([]string, 0, 1+len(result.Hosts)+len(result.Passives)) + if result.Primary != "" { + // First in the list to speed up master discovery. + hosts = append(hosts, result.Primary) + } + hosts = append(hosts, result.Hosts...) + hosts = append(hosts, result.Passives...) + + debugf("SYNC %s knows about the following peers: %#v", addr, hosts) + return info, hosts, nil +} + +type syncKind bool + +const ( + completeSync syncKind = true + partialSync syncKind = false +) + +func (cluster *mongoCluster) addServer(server *mongoServer, info *mongoServerInfo, syncKind syncKind) { + cluster.Lock() + current := cluster.servers.Search(server.ResolvedAddr) + if current == nil { + if syncKind == partialSync { + cluster.Unlock() + server.Close() + log("SYNC Discarding unknown server ", server.Addr, " due to partial sync.") + return + } + cluster.servers.Add(server) + if info.Master { + cluster.masters.Add(server) + log("SYNC Adding ", server.Addr, " to cluster as a master.") + } else { + log("SYNC Adding ", server.Addr, " to cluster as a slave.") + } + } else { + if server != current { + panic("addServer attempting to add duplicated server") + } + if server.Info().Master != info.Master { + if info.Master { + log("SYNC Server ", server.Addr, " is now a master.") + cluster.masters.Add(server) + } else { + log("SYNC Server ", server.Addr, " is now a slave.") + cluster.masters.Remove(server) + } + } + } + server.SetInfo(info) + debugf("SYNC Broadcasting availability of server %s", server.Addr) + cluster.serverSynced.Broadcast() + cluster.Unlock() +} + +func (cluster *mongoCluster) getKnownAddrs() []string { + cluster.RLock() + max := len(cluster.userSeeds) + len(cluster.dynaSeeds) + cluster.servers.Len() + seen := make(map[string]bool, max) + known := make([]string, 0, max) + + add := func(addr string) { + if _, found := seen[addr]; !found { + seen[addr] = true + known = append(known, addr) + } + } + + for _, addr := range cluster.userSeeds { + add(addr) + } + for _, addr := range cluster.dynaSeeds { + add(addr) + } + for _, serv := range cluster.servers.Slice() { + add(serv.Addr) + } + cluster.RUnlock() + + return known +} + +// syncServers injects a value into the cluster.sync channel to force +// an iteration of the syncServersLoop function. +func (cluster *mongoCluster) syncServers() { + select { + case cluster.sync <- true: + default: + } +} + +// How long to wait for a checkup of the cluster topology if nothing +// else kicks a synchronization before that. +const syncServersDelay = 30 * time.Second +const syncShortDelay = 500 * time.Millisecond + +// syncServersLoop loops while the cluster is alive to keep its idea of +// the server topology up-to-date. It must be called just once from +// newCluster. The loop iterates once syncServersDelay has passed, or +// if somebody injects a value into the cluster.sync channel to force a +// synchronization. A loop iteration will contact all servers in +// parallel, ask them about known peers and their own role within the +// cluster, and then attempt to do the same with all the peers +// retrieved. +func (cluster *mongoCluster) syncServersLoop() { + for { + debugf("SYNC Cluster %p is starting a sync loop iteration.", cluster) + + cluster.Lock() + if cluster.references == 0 { + cluster.Unlock() + break + } + cluster.references++ // Keep alive while syncing. + direct := cluster.direct + cluster.Unlock() + + cluster.syncServersIteration(direct) + + // We just synchronized, so consume any outstanding requests. + select { + case <-cluster.sync: + default: + } + + cluster.Release() + + // Hold off before allowing another sync. No point in + // burning CPU looking for down servers. + if !cluster.failFast { + time.Sleep(syncShortDelay) + } + + cluster.Lock() + if cluster.references == 0 { + cluster.Unlock() + break + } + cluster.syncCount++ + // Poke all waiters so they have a chance to timeout or + // restart syncing if they wish to. + cluster.serverSynced.Broadcast() + // Check if we have to restart immediately either way. + restart := !direct && cluster.masters.Empty() || cluster.servers.Empty() + cluster.Unlock() + + if restart { + log("SYNC No masters found. Will synchronize again.") + time.Sleep(syncShortDelay) + continue + } + + debugf("SYNC Cluster %p waiting for next requested or scheduled sync.", cluster) + + // Hold off until somebody explicitly requests a synchronization + // or it's time to check for a cluster topology change again. + select { + case <-cluster.sync: + case <-time.After(syncServersDelay): + } + } + debugf("SYNC Cluster %p is stopping its sync loop.", cluster) +} + +func (cluster *mongoCluster) server(addr string, tcpaddr *net.TCPAddr) *mongoServer { + cluster.RLock() + server := cluster.servers.Search(tcpaddr.String()) + cluster.RUnlock() + if server != nil { + return server + } + return newServer(addr, tcpaddr, cluster.sync, cluster.dial) +} + +func resolveAddr(addr string) (*net.TCPAddr, error) { + // Simple cases that do not need actual resolution. Works with IPv4 and v6. + if host, port, err := net.SplitHostPort(addr); err == nil { + if port, _ := strconv.Atoi(port); port > 0 { + zone := "" + if i := strings.LastIndex(host, "%"); i >= 0 { + zone = host[i+1:] + host = host[:i] + } + ip := net.ParseIP(host) + if ip != nil { + return &net.TCPAddr{IP: ip, Port: port, Zone: zone}, nil + } + } + } + + // Attempt to resolve IPv4 and v6 concurrently. + addrChan := make(chan *net.TCPAddr, 2) + for _, network := range []string{"udp4", "udp6"} { + network := network + go func() { + // The unfortunate UDP dialing hack allows having a timeout on address resolution. + conn, err := net.DialTimeout(network, addr, 10*time.Second) + if err != nil { + addrChan <- nil + } else { + addrChan <- (*net.TCPAddr)(conn.RemoteAddr().(*net.UDPAddr)) + conn.Close() + } + }() + } + + // Wait for the result of IPv4 and v6 resolution. Use IPv4 if available. + tcpaddr := <-addrChan + if tcpaddr == nil || len(tcpaddr.IP) != 4 { + var timeout <-chan time.Time + if tcpaddr != nil { + // Don't wait too long if an IPv6 address is known. + timeout = time.After(50 * time.Millisecond) + } + select { + case <-timeout: + case tcpaddr2 := <-addrChan: + if tcpaddr == nil || tcpaddr2 != nil { + // It's an IPv4 address or the only known address. Use it. + tcpaddr = tcpaddr2 + } + } + } + + if tcpaddr == nil { + log("SYNC Failed to resolve server address: ", addr) + return nil, errors.New("failed to resolve server address: " + addr) + } + if tcpaddr.String() != addr { + debug("SYNC Address ", addr, " resolved as ", tcpaddr.String()) + } + return tcpaddr, nil +} + +type pendingAdd struct { + server *mongoServer + info *mongoServerInfo +} + +func (cluster *mongoCluster) syncServersIteration(direct bool) { + log("SYNC Starting full topology synchronization...") + + var wg sync.WaitGroup + var m sync.Mutex + notYetAdded := make(map[string]pendingAdd) + addIfFound := make(map[string]bool) + seen := make(map[string]bool) + syncKind := partialSync + + var spawnSync func(addr string, byMaster bool) + spawnSync = func(addr string, byMaster bool) { + wg.Add(1) + go func() { + defer wg.Done() + + tcpaddr, err := resolveAddr(addr) + if err != nil { + log("SYNC Failed to start sync of ", addr, ": ", err.Error()) + return + } + resolvedAddr := tcpaddr.String() + + m.Lock() + if byMaster { + if pending, ok := notYetAdded[resolvedAddr]; ok { + delete(notYetAdded, resolvedAddr) + m.Unlock() + cluster.addServer(pending.server, pending.info, completeSync) + return + } + addIfFound[resolvedAddr] = true + } + if seen[resolvedAddr] { + m.Unlock() + return + } + seen[resolvedAddr] = true + m.Unlock() + + server := cluster.server(addr, tcpaddr) + info, hosts, err := cluster.syncServer(server) + if err != nil { + cluster.removeServer(server) + return + } + + m.Lock() + add := direct || info.Master || addIfFound[resolvedAddr] + if add { + syncKind = completeSync + } else { + notYetAdded[resolvedAddr] = pendingAdd{server, info} + } + m.Unlock() + if add { + cluster.addServer(server, info, completeSync) + } + if !direct { + for _, addr := range hosts { + spawnSync(addr, info.Master) + } + } + }() + } + + knownAddrs := cluster.getKnownAddrs() + for _, addr := range knownAddrs { + spawnSync(addr, false) + } + wg.Wait() + + if syncKind == completeSync { + logf("SYNC Synchronization was complete (got data from primary).") + for _, pending := range notYetAdded { + cluster.removeServer(pending.server) + } + } else { + logf("SYNC Synchronization was partial (cannot talk to primary).") + for _, pending := range notYetAdded { + cluster.addServer(pending.server, pending.info, partialSync) + } + } + + cluster.Lock() + mastersLen := cluster.masters.Len() + logf("SYNC Synchronization completed: %d master(s) and %d slave(s) alive.", mastersLen, cluster.servers.Len()-mastersLen) + + // Update dynamic seeds, but only if we have any good servers. Otherwise, + // leave them alone for better chances of a successful sync in the future. + if syncKind == completeSync { + dynaSeeds := make([]string, cluster.servers.Len()) + for i, server := range cluster.servers.Slice() { + dynaSeeds[i] = server.Addr + } + cluster.dynaSeeds = dynaSeeds + debugf("SYNC New dynamic seeds: %#v\n", dynaSeeds) + } + cluster.Unlock() +} + +// AcquireSocket returns a socket to a server in the cluster. If slaveOk is +// true, it will attempt to return a socket to a slave server. If it is +// false, the socket will necessarily be to a master server. +func (cluster *mongoCluster) AcquireSocket(mode Mode, slaveOk bool, syncTimeout time.Duration, socketTimeout time.Duration, serverTags []bson.D, poolLimit int) (s *mongoSocket, err error) { + var started time.Time + var syncCount uint + warnedLimit := false + for { + cluster.RLock() + for { + mastersLen := cluster.masters.Len() + slavesLen := cluster.servers.Len() - mastersLen + debugf("Cluster has %d known masters and %d known slaves.", mastersLen, slavesLen) + if !(slaveOk && mode == Secondary) && mastersLen > 0 || slaveOk && slavesLen > 0 { + break + } + if started.IsZero() { + // Initialize after fast path above. + started = time.Now() + syncCount = cluster.syncCount + } else if syncTimeout != 0 && started.Before(time.Now().Add(-syncTimeout)) || cluster.failFast && cluster.syncCount != syncCount { + cluster.RUnlock() + return nil, errors.New("no reachable servers") + } + log("Waiting for servers to synchronize...") + cluster.syncServers() + + // Remember: this will release and reacquire the lock. + cluster.serverSynced.Wait() + } + + var server *mongoServer + if slaveOk { + server = cluster.servers.BestFit(mode, serverTags) + } else { + server = cluster.masters.BestFit(mode, nil) + } + cluster.RUnlock() + + if server == nil { + // Must have failed the requested tags. Sleep to avoid spinning. + time.Sleep(1e8) + continue + } + + s, abended, err := server.AcquireSocket(poolLimit, socketTimeout) + if err == errPoolLimit { + if !warnedLimit { + warnedLimit = true + log("WARNING: Per-server connection limit reached.") + } + time.Sleep(100 * time.Millisecond) + continue + } + if err != nil { + cluster.removeServer(server) + cluster.syncServers() + continue + } + if abended && !slaveOk { + var result isMasterResult + err := cluster.isMaster(s, &result) + if err != nil || !result.IsMaster { + logf("Cannot confirm server %s as master (%v)", server.Addr, err) + s.Release() + cluster.syncServers() + time.Sleep(100 * time.Millisecond) + continue + } + } + return s, nil + } + panic("unreached") +} + +func (cluster *mongoCluster) CacheIndex(cacheKey string, exists bool) { + cluster.Lock() + if cluster.cachedIndex == nil { + cluster.cachedIndex = make(map[string]bool) + } + if exists { + cluster.cachedIndex[cacheKey] = true + } else { + delete(cluster.cachedIndex, cacheKey) + } + cluster.Unlock() +} + +func (cluster *mongoCluster) HasCachedIndex(cacheKey string) (result bool) { + cluster.RLock() + if cluster.cachedIndex != nil { + result = cluster.cachedIndex[cacheKey] + } + cluster.RUnlock() + return +} + +func (cluster *mongoCluster) ResetIndexCache() { + cluster.Lock() + cluster.cachedIndex = make(map[string]bool) + cluster.Unlock() +} |