Example #1
0
// UpdateShardReplicationRecord is a low level function to add / update an
// entry to the ShardReplication object.
func UpdateShardReplicationRecord(ctx context.Context, ts Server, keyspace, shard string, tabletAlias, parent TabletAlias) error {
	span := trace.NewSpanFromContext(ctx)
	span.StartClient("TopoServer.UpdateShardReplicationFields")
	span.Annotate("keyspace", keyspace)
	span.Annotate("shard", shard)
	span.Annotate("tablet", tabletAlias.String())
	defer span.Finish()

	return ts.UpdateShardReplicationFields(tabletAlias.Cell, keyspace, shard, func(sr *ShardReplication) error {
		// not very efficient, but easy to read
		links := make([]ReplicationLink, 0, len(sr.ReplicationLinks)+1)
		found := false
		for _, link := range sr.ReplicationLinks {
			if link.TabletAlias == tabletAlias {
				if found {
					log.Warningf("Found a second ReplicationLink for tablet %v, deleting it", tabletAlias)
					continue
				}
				found = true
				// update the master
				link.Parent = parent
			}
			links = append(links, link)
		}
		if !found {
			links = append(links, ReplicationLink{TabletAlias: tabletAlias, Parent: parent})
		}
		sr.ReplicationLinks = links
		return nil
	})
}
Example #2
0
// UnlockShard unlocks a previously locked shard.
func (n *ActionNode) UnlockShard(ctx context.Context, ts topo.Server, keyspace, shard string, lockPath string, actionError error) error {
	span := trace.NewSpanFromContext(ctx)
	span.StartClient("TopoServer.UnlockShardForAction")
	span.Annotate("action", n.Action)
	span.Annotate("keyspace", keyspace)
	span.Annotate("shard", shard)
	defer span.Finish()

	// first update the actionNode
	if actionError != nil {
		log.Infof("Unlocking shard %v/%v for action %v with error %v", keyspace, shard, n.Action, actionError)
		n.Error = actionError.Error()
		n.State = ACTION_STATE_FAILED
	} else {
		log.Infof("Unlocking shard %v/%v for successful action %v", keyspace, shard, n.Action)
		n.Error = ""
		n.State = ACTION_STATE_DONE
	}
	err := ts.UnlockShardForAction(keyspace, shard, lockPath, n.ToJson())
	if actionError != nil {
		if err != nil {
			// this will be masked
			log.Warningf("UnlockShardForAction failed: %v", err)
		}
		return actionError
	}
	return err
}
Example #3
0
// GetTabletMap tries to read all the tablets in the provided list,
// and returns them all in a map.
// If error is ErrPartialResult, the results in the dictionary are
// incomplete, meaning some tablets couldn't be read.
func GetTabletMap(ctx context.Context, ts Server, tabletAliases []TabletAlias) (map[TabletAlias]*TabletInfo, error) {
	span := trace.NewSpanFromContext(ctx)
	span.StartLocal("topo.GetTabletMap")
	span.Annotate("num_tablets", len(tabletAliases))
	defer span.Finish()

	wg := sync.WaitGroup{}
	mutex := sync.Mutex{}

	tabletMap := make(map[TabletAlias]*TabletInfo)
	var someError error

	for _, tabletAlias := range tabletAliases {
		wg.Add(1)
		go func(tabletAlias TabletAlias) {
			defer wg.Done()
			tabletInfo, err := ts.GetTablet(tabletAlias)
			mutex.Lock()
			if err != nil {
				log.Warningf("%v: %v", tabletAlias, err)
				// There can be data races removing nodes - ignore them for now.
				if err != ErrNoNode {
					someError = ErrPartialResult
				}
			} else {
				tabletMap[tabletAlias] = tabletInfo
			}
			mutex.Unlock()
		}(tabletAlias)
	}
	wg.Wait()
	return tabletMap, someError
}
Example #4
0
// refreshTablet needs to be run after an action may have changed the current
// state of the tablet.
func (agent *ActionAgent) refreshTablet(ctx context.Context, reason string) error {
	log.Infof("Executing post-action state refresh")

	span := trace.NewSpanFromContext(ctx)
	span.StartLocal("ActionAgent.refreshTablet")
	span.Annotate("reason", reason)
	defer span.Finish()
	ctx = trace.NewContext(ctx, span)

	// Save the old tablet so callbacks can have a better idea of
	// the precise nature of the transition.
	oldTablet := agent.Tablet().Tablet

	// Actions should have side effects on the tablet, so reload the data.
	if err := agent.readTablet(); err != nil {
		log.Warningf("Failed rereading tablet after %v - services may be inconsistent: %v", reason, err)
		return fmt.Errorf("Failed rereading tablet after %v: %v", reason, err)
	}

	if updatedTablet := agent.checkTabletMysqlPort(agent.Tablet()); updatedTablet != nil {
		agent.mutex.Lock()
		agent._tablet = updatedTablet
		agent.mutex.Unlock()
	}

	if err := agent.updateState(ctx, oldTablet, reason); err != nil {
		return err
	}
	log.Infof("Done with post-action state refresh")
	return nil
}
Example #5
0
// LockKeyspace will lock the keyspace in the topology server.
// UnlockKeyspace should be called if this returns no error.
func (n *ActionNode) LockKeyspace(ctx context.Context, ts topo.Server, keyspace string, lockTimeout time.Duration, interrupted chan struct{}) (lockPath string, err error) {
	log.Infof("Locking keyspace %v for action %v", keyspace, n.Action)

	span := trace.NewSpanFromContext(ctx)
	span.StartClient("TopoServer.LockKeyspaceForAction")
	span.Annotate("action", n.Action)
	span.Annotate("keyspace", keyspace)
	defer span.Finish()

	return ts.LockKeyspaceForAction(keyspace, n.ToJson(), lockTimeout, interrupted)
}
Example #6
0
// LockSrvShard will lock the serving shard in the topology server.
// UnlockSrvShard should be called if this returns no error.
func (n *ActionNode) LockSrvShard(ctx context.Context, ts topo.Server, cell, keyspace, shard string, lockTimeout time.Duration, interrupted chan struct{}) (lockPath string, err error) {
	log.Infof("Locking serving shard %v/%v/%v for action %v", cell, keyspace, shard, n.Action)

	span := trace.NewSpanFromContext(ctx)
	span.StartClient("TopoServer.LockSrvShardForAction")
	span.Annotate("action", n.Action)
	span.Annotate("keyspace", keyspace)
	span.Annotate("shard", shard)
	span.Annotate("cell", cell)
	defer span.Finish()

	return ts.LockSrvShardForAction(cell, keyspace, shard, n.ToJson(), lockTimeout, interrupted)
}
Example #7
0
// UpdateTablet updates the tablet data only - not associated replication paths.
func UpdateTablet(ctx context.Context, ts Server, tablet *TabletInfo) error {
	span := trace.NewSpanFromContext(ctx)
	span.StartClient("TopoServer.UpdateTablet")
	span.Annotate("tablet", tablet.Alias.String())
	defer span.Finish()

	var version int64 = -1
	if tablet.version != 0 {
		version = tablet.version
	}

	newVersion, err := ts.UpdateTablet(tablet, version)
	if err == nil {
		tablet.version = newVersion
	}
	return err
}
Example #8
0
// UpdateShard updates the shard data, with the right version
func UpdateShard(ctx context.Context, ts Server, si *ShardInfo) error {
	span := trace.NewSpanFromContext(ctx)
	span.StartClient("TopoServer.UpdateShard")
	span.Annotate("keyspace", si.Keyspace())
	span.Annotate("shard", si.ShardName())
	defer span.Finish()

	var version int64 = -1
	if si.version != 0 {
		version = si.version
	}

	newVersion, err := ts.UpdateShard(si, version)
	if err == nil {
		si.version = newVersion
	}
	return err
}
Example #9
0
// Go invokes the function asynchronously.  It returns the Call structure representing
// the invocation.  The done channel will signal when the call is complete by returning
// the same Call object.  If done is nil, Go will allocate a new channel.
// If non-nil, done must be buffered or Go will deliberately crash.
func (client *Client) Go(ctx context.Context, serviceMethod string, args interface{}, reply interface{}, done chan *Call) *Call {
	span := trace.NewSpanFromContext(ctx)
	span.StartClient(serviceMethod)
	defer span.Finish()

	call := new(Call)
	call.ServiceMethod = serviceMethod
	call.Args = args
	call.Reply = reply
	if done == nil {
		done = make(chan *Call, 10) // buffered.
	} else {
		// If caller passes done != nil, it must arrange that
		// done has enough buffer for the number of simultaneous
		// RPCs that will be using that channel.  If the channel
		// is totally unbuffered, it's best not to run at all.
		if cap(done) == 0 {
			log.Panic("rpc: done channel is unbuffered")
		}
	}
	call.Done = done
	client.send(call)
	return call
}
Example #10
0
// Update shard file with new master, replicas, etc.
//
// Re-read from TopologyServer to make sure we are using the side
// effects of all actions.
//
// This function locks individual SvrShard paths, so it doesn't need a lock
// on the shard.
func RebuildShard(ctx context.Context, log logutil.Logger, ts topo.Server, keyspace, shard string, cells []string, timeout time.Duration, interrupted chan struct{}) (*topo.ShardInfo, error) {
	log.Infof("RebuildShard %v/%v", keyspace, shard)

	span := trace.NewSpanFromContext(ctx)
	span.StartLocal("topotools.RebuildShard")
	defer span.Finish()
	ctx = trace.NewContext(ctx, span)

	// read the existing shard info. It has to exist.
	shardInfo, err := ts.GetShard(keyspace, shard)
	if err != nil {
		return nil, err
	}

	// rebuild all cells in parallel
	wg := sync.WaitGroup{}
	rec := concurrency.AllErrorRecorder{}
	for _, cell := range shardInfo.Cells {
		// skip this cell if we shouldn't rebuild it
		if !topo.InCellList(cell, cells) {
			continue
		}

		// start with the master if it's in the current cell
		tabletsAsMap := make(map[topo.TabletAlias]bool)
		if shardInfo.MasterAlias.Cell == cell {
			tabletsAsMap[shardInfo.MasterAlias] = true
		}

		wg.Add(1)
		go func(cell string) {
			defer wg.Done()

			// Lock the SrvShard so we don't race with other rebuilds of the same
			// shard in the same cell (e.g. from our peer tablets).
			actionNode := actionnode.RebuildSrvShard()
			lockPath, err := actionNode.LockSrvShard(ctx, ts, cell, keyspace, shard, timeout, interrupted)
			if err != nil {
				rec.RecordError(err)
				return
			}

			// read the ShardReplication object to find tablets
			sri, err := ts.GetShardReplication(cell, keyspace, shard)
			if err != nil {
				rec.RecordError(fmt.Errorf("GetShardReplication(%v, %v, %v) failed: %v", cell, keyspace, shard, err))
				return
			}

			// add all relevant tablets to the map
			for _, rl := range sri.ReplicationLinks {
				tabletsAsMap[rl.TabletAlias] = true
				if rl.Parent.Cell == cell {
					tabletsAsMap[rl.Parent] = true
				}
			}

			// convert the map to a list
			aliases := make([]topo.TabletAlias, 0, len(tabletsAsMap))
			for a := range tabletsAsMap {
				aliases = append(aliases, a)
			}

			// read all the Tablet records
			tablets, err := topo.GetTabletMap(ctx, ts, aliases)
			switch err {
			case nil:
				// keep going, we're good
			case topo.ErrPartialResult:
				log.Warningf("Got ErrPartialResult from topo.GetTabletMap in cell %v, some tablets may not be added properly to serving graph", cell)
			default:
				rec.RecordError(fmt.Errorf("GetTabletMap in cell %v failed: %v", cell, err))
				return
			}

			// write the data we need to
			rebuildErr := rebuildCellSrvShard(ctx, log, ts, shardInfo, cell, tablets)

			// and unlock
			if err := actionNode.UnlockSrvShard(ctx, ts, cell, keyspace, shard, lockPath, rebuildErr); err != nil {
				rec.RecordError(err)
			}
		}(cell)
	}
	wg.Wait()

	return shardInfo, rec.Error()
}
Example #11
0
// rebuildCellSrvShard computes and writes the serving graph data to a
// single cell
func rebuildCellSrvShard(ctx context.Context, log logutil.Logger, ts topo.Server, shardInfo *topo.ShardInfo, cell string, tablets map[topo.TabletAlias]*topo.TabletInfo) error {
	log.Infof("rebuildCellSrvShard %v/%v in cell %v", shardInfo.Keyspace(), shardInfo.ShardName(), cell)

	// Get all existing db types so they can be removed if nothing
	// had been edited.
	existingTabletTypes, err := ts.GetSrvTabletTypesPerShard(cell, shardInfo.Keyspace(), shardInfo.ShardName())
	if err != nil {
		if err != topo.ErrNoNode {
			return err
		}
	}

	// Update db type addresses in the serving graph
	//
	// locationAddrsMap is a map:
	//   key: tabletType
	//   value: EndPoints (list of server records)
	locationAddrsMap := make(map[topo.TabletType]*topo.EndPoints)
	for _, tablet := range tablets {
		if !tablet.IsInReplicationGraph() {
			// only valid case is a scrapped master in the
			// catastrophic reparent case
			if tablet.Parent.Uid != topo.NO_TABLET {
				log.Warningf("Tablet %v should not be in the replication graph, please investigate (it is being ignored in the rebuild)", tablet.Alias)
			}
			continue
		}

		// Check IsInServingGraph, we don't want to add tablets that
		// are not serving
		if !tablet.IsInServingGraph() {
			continue
		}

		// Check the Keyspace and Shard for the tablet are right
		if tablet.Keyspace != shardInfo.Keyspace() || tablet.Shard != shardInfo.ShardName() {
			return fmt.Errorf("CRITICAL: tablet %v is in replication graph for shard %v/%v but belongs to shard %v:%v", tablet.Alias, shardInfo.Keyspace(), shardInfo.ShardName(), tablet.Keyspace, tablet.Shard)
		}

		// Add the tablet to the list
		addrs, ok := locationAddrsMap[tablet.Type]
		if !ok {
			addrs = topo.NewEndPoints()
			locationAddrsMap[tablet.Type] = addrs
		}
		entry, err := tablet.Tablet.EndPoint()
		if err != nil {
			log.Warningf("EndPointForTablet failed for tablet %v: %v", tablet.Alias, err)
			continue
		}
		addrs.Entries = append(addrs.Entries, *entry)
	}

	// we're gonna parallelize a lot here:
	// - writing all the tabletTypes records
	// - removing the unused records
	// - writing SrvShard
	rec := concurrency.AllErrorRecorder{}
	wg := sync.WaitGroup{}

	// write all the EndPoints nodes everywhere we want them
	for tabletType, addrs := range locationAddrsMap {
		wg.Add(1)
		go func(tabletType topo.TabletType, addrs *topo.EndPoints) {
			log.Infof("saving serving graph for cell %v shard %v/%v tabletType %v", cell, shardInfo.Keyspace(), shardInfo.ShardName(), tabletType)
			span := trace.NewSpanFromContext(ctx)
			span.StartClient("TopoServer.UpdateEndPoints")
			span.Annotate("tablet_type", string(tabletType))
			if err := ts.UpdateEndPoints(cell, shardInfo.Keyspace(), shardInfo.ShardName(), tabletType, addrs); err != nil {
				rec.RecordError(fmt.Errorf("writing endpoints for cell %v shard %v/%v tabletType %v failed: %v", cell, shardInfo.Keyspace(), shardInfo.ShardName(), tabletType, err))
			}
			span.Finish()
			wg.Done()
		}(tabletType, addrs)
	}

	// Delete any pre-existing paths that were not updated by this process.
	// That's the existingTabletTypes - locationAddrsMap
	for _, tabletType := range existingTabletTypes {
		if _, ok := locationAddrsMap[tabletType]; !ok {
			wg.Add(1)
			go func(tabletType topo.TabletType) {
				log.Infof("removing stale db type from serving graph: %v", tabletType)
				span := trace.NewSpanFromContext(ctx)
				span.StartClient("TopoServer.DeleteEndPoints")
				span.Annotate("tablet_type", string(tabletType))
				if err := ts.DeleteEndPoints(cell, shardInfo.Keyspace(), shardInfo.ShardName(), tabletType); err != nil {
					log.Warningf("unable to remove stale db type %v from serving graph: %v", tabletType, err)
				}
				span.Finish()
				wg.Done()
			}(tabletType)
		}
	}

	// Update srvShard object
	wg.Add(1)
	go func() {
		log.Infof("updating shard serving graph in cell %v for %v/%v", cell, shardInfo.Keyspace(), shardInfo.ShardName())
		srvShard := &topo.SrvShard{
			Name:        shardInfo.ShardName(),
			KeyRange:    shardInfo.KeyRange,
			ServedTypes: shardInfo.GetServedTypesPerCell(cell),
			MasterCell:  shardInfo.MasterAlias.Cell,
			TabletTypes: make([]topo.TabletType, 0, len(locationAddrsMap)),
		}
		for tabletType := range locationAddrsMap {
			srvShard.TabletTypes = append(srvShard.TabletTypes, tabletType)
		}

		span := trace.NewSpanFromContext(ctx)
		span.StartClient("TopoServer.UpdateSrvShard")
		span.Annotate("keyspace", shardInfo.Keyspace())
		span.Annotate("shard", shardInfo.ShardName())
		span.Annotate("cell", cell)
		if err := ts.UpdateSrvShard(cell, shardInfo.Keyspace(), shardInfo.ShardName(), srvShard); err != nil {
			rec.RecordError(fmt.Errorf("writing serving data in cell %v for %v/%v failed: %v", cell, shardInfo.Keyspace(), shardInfo.ShardName(), err))
		}
		span.Finish()
		wg.Done()
	}()

	wg.Wait()
	return rec.Error()
}
Example #12
0
// FindAllTabletAliasesInShard uses the replication graph to find all the
// tablet aliases in the given shard.
// It can return ErrPartialResult if some cells were not fetched,
// in which case the result only contains the cells that were fetched.
func FindAllTabletAliasesInShardByCell(ctx context.Context, ts Server, keyspace, shard string, cells []string) ([]TabletAlias, error) {
	span := trace.NewSpanFromContext(ctx)
	span.StartLocal("topo.FindAllTabletAliasesInShardbyCell")
	span.Annotate("keyspace", keyspace)
	span.Annotate("shard", shard)
	span.Annotate("num_cells", len(cells))
	defer span.Finish()

	// read the shard information to find the cells
	si, err := ts.GetShard(keyspace, shard)
	if err != nil {
		return nil, err
	}

	resultAsMap := make(map[TabletAlias]bool)
	if !si.MasterAlias.IsZero() {
		if InCellList(si.MasterAlias.Cell, cells) {
			resultAsMap[si.MasterAlias] = true
		}
	}

	// read the replication graph in each cell and add all found tablets
	wg := sync.WaitGroup{}
	mutex := sync.Mutex{}
	rec := concurrency.AllErrorRecorder{}
	for _, cell := range si.Cells {
		if !InCellList(cell, cells) {
			continue
		}
		wg.Add(1)
		go func(cell string) {
			defer wg.Done()
			sri, err := ts.GetShardReplication(cell, keyspace, shard)
			if err != nil {
				rec.RecordError(fmt.Errorf("GetShardReplication(%v, %v, %v) failed: %v", cell, keyspace, shard, err))
				return
			}

			mutex.Lock()
			for _, rl := range sri.ReplicationLinks {
				resultAsMap[rl.TabletAlias] = true
				if !rl.Parent.IsZero() && InCellList(rl.Parent.Cell, cells) {
					resultAsMap[rl.Parent] = true
				}
			}
			mutex.Unlock()
		}(cell)
	}
	wg.Wait()
	err = nil
	if rec.HasErrors() {
		log.Warningf("FindAllTabletAliasesInShard(%v,%v): got partial result: %v", keyspace, shard, rec.Error())
		err = ErrPartialResult
	}

	result := make([]TabletAlias, 0, len(resultAsMap))
	for a := range resultAsMap {
		result = append(result, a)
	}
	return result, err
}
Example #13
0
// changeCallback is run after every action that might
// have changed something in the tablet record.
func (agent *ActionAgent) changeCallback(ctx context.Context, oldTablet, newTablet *topo.Tablet) error {
	span := trace.NewSpanFromContext(ctx)
	span.StartLocal("ActionAgent.changeCallback")
	defer span.Finish()

	allowQuery := newTablet.IsRunningQueryService()

	// Read the shard to get SourceShards / TabletControlMap if
	// we're going to use it.
	var shardInfo *topo.ShardInfo
	var tabletControl *topo.TabletControl
	var blacklistedTables []string
	var err error
	if allowQuery {
		shardInfo, err = agent.TopoServer.GetShard(newTablet.Keyspace, newTablet.Shard)
		if err != nil {
			log.Errorf("Cannot read shard for this tablet %v, might have inaccurate SourceShards and TabletControls: %v", newTablet.Alias, err)
		} else {
			if newTablet.Type == topo.TYPE_MASTER {
				allowQuery = len(shardInfo.SourceShards) == 0
			}
			if tc, ok := shardInfo.TabletControlMap[newTablet.Type]; ok {
				if topo.InCellList(newTablet.Alias.Cell, tc.Cells) {
					if tc.DisableQueryService {
						allowQuery = false
					}
					blacklistedTables = tc.BlacklistedTables
					tabletControl = tc
				}
			}
		}
	}

	// Read the keyspace on masters to get ShardingColumnType,
	// for binlog replication, only if source shards are set.
	var keyspaceInfo *topo.KeyspaceInfo
	if newTablet.Type == topo.TYPE_MASTER && shardInfo != nil && len(shardInfo.SourceShards) > 0 {
		keyspaceInfo, err = agent.TopoServer.GetKeyspace(newTablet.Keyspace)
		if err != nil {
			log.Errorf("Cannot read keyspace for this tablet %v: %v", newTablet.Alias, err)
			keyspaceInfo = nil
		}
	}

	if allowQuery {
		// There are a few transitions when we're
		// going to need to restart the query service:
		// - transitioning from replica to master, so clients
		//   that were already connected don't keep on using
		//   the master as replica or rdonly.
		// - having different parameters for the query
		//   service. It needs to stop and restart with the
		//   new parameters. That includes:
		//   - changing KeyRange
		//   - changing the BlacklistedTables list
		if (newTablet.Type == topo.TYPE_MASTER &&
			oldTablet.Type != topo.TYPE_MASTER) ||
			(newTablet.KeyRange != oldTablet.KeyRange) ||
			!reflect.DeepEqual(blacklistedTables, agent.BlacklistedTables()) {
			agent.disallowQueries()
		}
		if err := agent.allowQueries(newTablet, blacklistedTables); err != nil {
			log.Errorf("Cannot start query service: %v", err)
		}
	} else {
		agent.disallowQueries()
	}

	// save the tabletControl we've been using, so the background
	// healthcheck makes the same decisions as we've been making.
	agent.setTabletControl(tabletControl)

	// update stream needs to be started or stopped too
	if agent.DBConfigs != nil {
		if topo.IsRunningUpdateStream(newTablet.Type) {
			binlog.EnableUpdateStreamService(agent.DBConfigs.App.DbName, agent.Mysqld)
		} else {
			binlog.DisableUpdateStreamService()
		}
	}

	statsType.Set(string(newTablet.Type))
	statsKeyspace.Set(newTablet.Keyspace)
	statsShard.Set(newTablet.Shard)
	statsKeyRangeStart.Set(string(newTablet.KeyRange.Start.Hex()))
	statsKeyRangeEnd.Set(string(newTablet.KeyRange.End.Hex()))

	// See if we need to start or stop any binlog player
	if agent.BinlogPlayerMap != nil {
		if newTablet.Type == topo.TYPE_MASTER {
			agent.BinlogPlayerMap.RefreshMap(newTablet, keyspaceInfo, shardInfo)
		} else {
			agent.BinlogPlayerMap.StopAllPlayersAndReset()
		}
	}
	return nil
}