Esempio n. 1
0
// UpdateTabletEndpoints fixes up any entries in the serving graph that relate
// to a given tablet.
func UpdateTabletEndpoints(ctx context.Context, ts topo.Server, tablet *topo.Tablet) (err error) {
	if *lockSrvShard {
		// This lock is only necessary until all tablets are upgraded to lock-free.
		actionNode := actionnode.RebuildSrvShard()
		lockPath, err := actionNode.LockSrvShard(ctx, ts, tablet.Alias.Cell, tablet.Keyspace, tablet.Shard)
		if err != nil {
			return fmt.Errorf("can't lock shard for UpdateTabletEndpoints(%v): %v", tablet, err)
		}

		defer func() {
			actionNode.UnlockSrvShard(ctx, ts, tablet.Alias.Cell, tablet.Keyspace, tablet.Shard, lockPath, err)
		}()
	}

	srvTypes, err := ts.GetSrvTabletTypesPerShard(ctx, tablet.Alias.Cell, tablet.Keyspace, tablet.Shard)
	if err != nil {
		if err != topo.ErrNoNode {
			return err
		}
		// It's fine if there are no existing types.
		srvTypes = nil
	}

	wg := sync.WaitGroup{}
	errs := concurrency.AllErrorRecorder{}

	// Update the list that the tablet is supposed to be in (if any).
	if tablet.IsInServingGraph() {
		endpoint, err := tablet.EndPoint()
		if err != nil {
			return err
		}

		wg.Add(1)
		go func() {
			defer wg.Done()
			errs.RecordError(
				updateEndpoint(ctx, ts, tablet.Alias.Cell, tablet.Keyspace, tablet.Shard,
					tablet.Type, endpoint))
		}()
	}

	// Remove it from any other lists it isn't supposed to be in.
	for _, srvType := range srvTypes {
		if srvType != tablet.Type {
			wg.Add(1)
			go func(tabletType topo.TabletType) {
				defer wg.Done()
				errs.RecordError(
					removeEndpoint(ctx, ts, tablet.Alias.Cell, tablet.Keyspace, tablet.Shard,
						tabletType, tablet.Alias.Uid))
			}(srvType)
		}
	}

	wg.Wait()
	return errs.Error()
}
Esempio n. 2
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(log logutil.Logger, ts topo.Server, keyspace, shard string, cells []string, timeout time.Duration, interrupted chan struct{}) error {
	log.Infof("RebuildShard %v/%v", keyspace, shard)

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

			// 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(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
			}

			// Lock the SrvShard so we write a consistent data set.
			actionNode := actionnode.RebuildSrvShard()
			lockPath, err := actionNode.LockSrvShard(ts, cell, keyspace, shard, timeout, interrupted)
			if err != nil {
				rec.RecordError(err)
				return
			}

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

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

	return rec.Error()
}
Esempio n. 3
0
// rebuildCellSrvShard computes and writes the serving graph data to a
// single cell
func rebuildCellSrvShard(ctx context.Context, log logutil.Logger, ts topo.Server, si *topo.ShardInfo, cell string) (err error) {
	log.Infof("rebuildCellSrvShard %v/%v in cell %v", si.Keyspace(), si.ShardName(), cell)

	if *lockSrvShard {
		// This lock is only necessary until all tablets are upgraded to lock-free.
		actionNode := actionnode.RebuildSrvShard()
		lockPath, err := actionNode.LockSrvShard(ctx, ts, cell, si.Keyspace(), si.ShardName())
		if err != nil {
			return fmt.Errorf("can't lock SrvShard for rebuild: %v", err)
		}

		defer func() {
			actionNode.UnlockSrvShard(ctx, ts, cell, si.Keyspace(), si.ShardName(), lockPath, err)
		}()
	}

	for {
		select {
		case <-ctx.Done():
			return ctx.Err()
		default:
		}

		// Read existing EndPoints node versions, so we know if any
		// changes sneak in after we read the tablets.
		versions, err := getEndPointsVersions(ctx, ts, cell, si.Keyspace(), si.ShardName())

		// Get all tablets in this cell/shard.
		tablets, err := topo.GetTabletMapForShardByCell(ctx, ts, si.Keyspace(), si.ShardName(), []string{cell})
		if err != nil {
			if err != topo.ErrPartialResult {
				return err
			}
			log.Warningf("Got ErrPartialResult from topo.GetTabletMapForShardByCell(%v), some tablets may not be added properly to serving graph", cell)
		}

		// Build up the serving graph from scratch.
		serving := 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
				log.Warningf("Tablet %v should not be in the replication graph, please investigate (it is being ignored in the rebuild)", tablet.Alias)
				continue
			}

			// Only add serving types.
			if !tablet.IsInServingGraph() {
				continue
			}

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

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

		wg := sync.WaitGroup{}
		fatalErrs := concurrency.AllErrorRecorder{}
		retryErrs := concurrency.AllErrorRecorder{}

		// Write nodes that should exist.
		for tabletType, endpoints := range serving {
			wg.Add(1)
			go func(tabletType topo.TabletType, endpoints *topo.EndPoints) {
				defer wg.Done()

				log.Infof("saving serving graph for cell %v shard %v/%v tabletType %v", cell, si.Keyspace(), si.ShardName(), tabletType)

				version, ok := versions[tabletType]
				if !ok {
					// This type didn't exist when we first checked.
					// Try to create, but only if it still doesn't exist.
					if err := ts.CreateEndPoints(ctx, cell, si.Keyspace(), si.ShardName(), tabletType, endpoints); err != nil {
						log.Warningf("CreateEndPoints(%v, %v, %v) failed during rebuild: %v", cell, si, tabletType, err)
						switch err {
						case topo.ErrNodeExists:
							retryErrs.RecordError(err)
						default:
							fatalErrs.RecordError(err)
						}
					}
					return
				}

				// Update only if the version matches.
				if err := ts.UpdateEndPoints(ctx, cell, si.Keyspace(), si.ShardName(), tabletType, endpoints, version); err != nil {
					log.Warningf("UpdateEndPoints(%v, %v, %v) failed during rebuild: %v", cell, si, tabletType, err)
					switch err {
					case topo.ErrBadVersion, topo.ErrNoNode:
						retryErrs.RecordError(err)
					default:
						fatalErrs.RecordError(err)
					}
				}
			}(tabletType, endpoints)
		}

		// Delete nodes that shouldn't exist.
		for tabletType, version := range versions {
			if _, ok := serving[tabletType]; !ok {
				wg.Add(1)
				go func(tabletType topo.TabletType, version int64) {
					defer wg.Done()
					log.Infof("removing stale db type from serving graph: %v", tabletType)
					if err := ts.DeleteEndPoints(ctx, cell, si.Keyspace(), si.ShardName(), tabletType, version); err != nil && err != topo.ErrNoNode {
						log.Warningf("DeleteEndPoints(%v, %v, %v) failed during rebuild: %v", cell, si, tabletType, err)
						switch err {
						case topo.ErrNoNode:
							// Someone else deleted it, which is fine.
						case topo.ErrBadVersion:
							retryErrs.RecordError(err)
						default:
							fatalErrs.RecordError(err)
						}
					}
				}(tabletType, version)
			}
		}

		// Update srvShard object
		wg.Add(1)
		go func() {
			defer wg.Done()
			log.Infof("updating shard serving graph in cell %v for %v/%v", cell, si.Keyspace(), si.ShardName())
			if err := UpdateSrvShard(ctx, ts, cell, si); err != nil {
				fatalErrs.RecordError(err)
				log.Warningf("writing serving data in cell %v for %v/%v failed: %v", cell, si.Keyspace(), si.ShardName(), err)
			}
		}()

		wg.Wait()

		// If there are any fatal errors, give up.
		if fatalErrs.HasErrors() {
			return fatalErrs.Error()
		}
		// If there are any retry errors, try again.
		if retryErrs.HasErrors() {
			continue
		}
		// Otherwise, success!
		return nil
	}
}