// rebuildCellSrvShard computes and writes the serving graph data to a
// single cell
func rebuildCellSrvShard(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)
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))
}
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)
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)
}
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)
}
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))
}
wg.Done()
}()
wg.Wait()
return rec.Error()
}