Golang Tablet.IsRunningQueryService方法代碼示例

// 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
}