topotools

Documentation

Overview

Package topotools contains high level functions based on vt/topo and vt/actionnode. It should not depend on anything else that's higher level. In particular, it cannot depend on:

• vt/wrangler: much higher level, wrangler depends on topotools.
• vt/tabletmanager/initiator: we don't want the various remote protocol dependencies here.

topotools is used by wrangler, so it ends up in all tools using wrangler (vtctl, vtctld, ...). It is also included by vttablet, so it contains:

• most of the logic to rebuild a shard serving graph (helthcheck module)
• some of the logic to perform a TabletExternallyReparented (RPC call to master vttablet to let it know it's the master).

Index

• Variables
• func ChangeType(ctx context.Context, ts topo.Server, tabletAlias topo.TabletAlias, ...) error
• func ConfigureTabletHook(hk *hook.Hook, tabletAlias topo.TabletAlias)
• func CopyMapKeys(m interface{}, typeHint interface{}) interface{}
• func CopyMapValues(m interface{}, typeHint interface{}) interface{}
• func FindTabletByIPAddrAndPort(tabletMap map[topo.TabletAlias]*topo.TabletInfo, addr, portName string, ...) (topo.TabletAlias, error)
• func GetAllTablets(ctx context.Context, ts topo.Server, cell string) ([]*topo.TabletInfo, error)
• func GetAllTabletsAcrossCells(ctx context.Context, ts topo.Server) ([]*topo.TabletInfo, error)
• func MapKeys(m interface{}) []interface{}
• func RebuildShard(ctx context.Context, log logutil.Logger, ts topo.Server, ...) (*topo.ShardInfo, error)
• func RestartSlavesExternal(ts topo.Server, log logutil.Logger, ...)
• func Scrap(ctx context.Context, ts topo.Server, tabletAlias topo.TabletAlias, force bool) error
• func SortedTabletMap(tabletMap map[topo.TabletAlias]*topo.TabletInfo) (map[topo.TabletAlias]*topo.TabletInfo, map[topo.TabletAlias]*topo.TabletInfo)
• type KeyspaceNodes
  • func (ks KeyspaceNodes) HasType(tabletType topo.TabletType) bool
  • func (ks KeyspaceNodes) TabletTypes() []topo.TabletType
• type OverlappingShards
  • func FindOverlappingShards(ts topo.Server, keyspace string) ([]*OverlappingShards, error)
  • func OverlappingShardsForShard(os []*OverlappingShards, shardName string) *OverlappingShards
  • func (os *OverlappingShards) ContainsShard(shardName string) bool
• type ServingGraph
  • func DbServingGraph(ts topo.Server, cell string) (servingGraph *ServingGraph)
• type ShardNodes
• type TabletNode
  • func (tn *TabletNode) ShortName() string
• type TabletNodesByType
• type Topology
  • func DbTopology(ctx context.Context, ts topo.Server) (*Topology, error)

Variables

var UseSrvShardLocks = flag.Bool("use_srv_shard_locks", true, "DEPRECATED: If true, takes the SrvShard lock for each shard being rebuilt")

UseSrvShardLocks is a deprecated flag. We leave it here until it's removed from all invocations of the tools.

Functions

func ChangeType

func ChangeType(ctx context.Context, ts topo.Server, tabletAlias topo.TabletAlias, newType topo.TabletType, health map[string]string) error

ChangeType changes the type of the tablet and possibly also updates the health informaton for it. Make this external, since these transitions need to be forced from time to time.

- if health is nil, we don't touch the Tablet's Health record. - if health is an empty map, we clear the Tablet's Health record. - if health has values, we overwrite the Tablet's Health record.

func ConfigureTabletHook

func ConfigureTabletHook(hk *hook.Hook, tabletAlias topo.TabletAlias)

ConfigureTabletHook configures the right parameters for a hook running locally on a tablet.

func CopyMapKeys

func CopyMapKeys(m interface{}, typeHint interface{}) interface{}

CopyMapKeys copies keys from from map m into a new slice with the type specified by typeHint. Reflection can't make a new slice type just based on the key type AFAICT.

func CopyMapValues

func CopyMapValues(m interface{}, typeHint interface{}) interface{}

CopyMapValues copies values from from map m into a new slice with the type specified by typeHint. Reflection can't make a new slice type just based on the key type AFAICT.

func FindTabletByIPAddrAndPort

func FindTabletByIPAddrAndPort(tabletMap map[topo.TabletAlias]*topo.TabletInfo, addr, portName string, port int) (topo.TabletAlias, error)

FindTabletByIPAddrAndPort searches within a tablet map for tablets

func GetAllTablets

func GetAllTablets(ctx context.Context, ts topo.Server, cell string) ([]*topo.TabletInfo, error)

GetAllTablets returns a sorted list of tablets.

func GetAllTabletsAcrossCells

func GetAllTabletsAcrossCells(ctx context.Context, ts topo.Server) ([]*topo.TabletInfo, error)

GetAllTabletsAcrossCells returns all tablets from known cells. If it returns topo.ErrPartialResult, then the list is valid, but partial.

func MapKeys

func MapKeys(m interface{}) []interface{}

MapKeys returns an array with th provided map keys.

func RebuildShard

func RebuildShard(ctx context.Context, log logutil.Logger, ts topo.Server, keyspace, shard string, cells []string, lockTimeout time.Duration) (*topo.ShardInfo, error)

RebuildShard updates the SrvShard objects and underlying serving graph.

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 RestartSlavesExternal

func RestartSlavesExternal(ts topo.Server, log logutil.Logger, slaveTabletMap, masterTabletMap map[topo.TabletAlias]*topo.TabletInfo, masterElectTabletAlias topo.TabletAlias, slaveWasRestarted func(*topo.TabletInfo, *actionnode.SlaveWasRestartedArgs) error)

RestartSlavesExternal will tell all the slaves in the provided list that they have a new master, and also tell all the masters. The masters will be scrapped if they don't answer. We execute all the actions in parallel.

func Scrap

func Scrap(ctx context.Context, ts topo.Server, tabletAlias topo.TabletAlias, force bool) error

Scrap will update the tablet type to 'Scrap', and remove it from the serving graph.

'force' means we are not on the tablet being scrapped, so it is probably dead. So if 'force' is true, we will also remove pending remote actions. And if 'force' is false, we also run an optional hook.

func SortedTabletMap

func SortedTabletMap(tabletMap map[topo.TabletAlias]*topo.TabletInfo) (map[topo.TabletAlias]*topo.TabletInfo, map[topo.TabletAlias]*topo.TabletInfo)

SortedTabletMap returns two maps:

• The slaveMap contains all the non-master non-scrapped hosts. This can be used as a list of slaves to fix up for reparenting
• The masterMap contains all the tablets without parents (scrapped or not). This can be used to special case the old master, and any tablet in a weird state, left over, ...

Types

type KeyspaceNodes

type KeyspaceNodes struct {
	ShardNodes []*ShardNodes // sorted by shard name
	ServedFrom map[topo.TabletType]string
}

KeyspaceNodes represents all tablet nodes in a keyspace.

func (KeyspaceNodes) HasType

func (ks KeyspaceNodes) HasType(tabletType topo.TabletType) bool

HasType returns true if ks has any tablets with the named type.

func (KeyspaceNodes) TabletTypes

func (ks KeyspaceNodes) TabletTypes() []topo.TabletType

TabletTypes returns a slice of tablet type names this ks contains.

type OverlappingShards

type OverlappingShards struct {
	Left  []*topo.ShardInfo
	Right []*topo.ShardInfo
}

OverlappingShards contains sets of shards that overlap which each-other. With this library, there is no guarantee of which set will be left or right.

func FindOverlappingShards

func FindOverlappingShards(ts topo.Server, keyspace string) ([]*OverlappingShards, error)

FindOverlappingShards will return an array of OverlappingShards for the provided keyspace. We do not support more than two overlapping shards (for instance, having 40-80, 40-60 and 40-50 in the same keyspace is not supported and will return an error). If shards don't perfectly overlap, they are not returned.

func OverlappingShardsForShard

func OverlappingShardsForShard(os []*OverlappingShards, shardName string) *OverlappingShards

OverlappingShardsForShard returns the OverlappingShards object from the list that has he provided shard, or nil

func (*OverlappingShards) ContainsShard

func (os *OverlappingShards) ContainsShard(shardName string) bool

ContainsShard returns true if either Left or Right lists contain the provided Shard.

type ServingGraph

type ServingGraph struct {
	Cell      string
	Keyspaces map[string]*KeyspaceNodes // indexed by keyspace name
	Errors    []string                  // collected during creation
}

ServingGraph contains the representation of the serving graph for a given cell.

func DbServingGraph

func DbServingGraph(ts topo.Server, cell string) (servingGraph *ServingGraph)

DbServingGraph returns the ServingGraph for the given cell.

type ShardNodes

type ShardNodes struct {
	Name        string
	TabletNodes TabletNodesByType
	ServedTypes []topo.TabletType
	Tag         interface{} // Tag is an arbitrary value manageable by a plugin.
}

ShardNodes represents all tablet nodes for a shard, indexed by tablet type.

type TabletNode

type TabletNode struct {
	Host  string
	Alias topo.TabletAlias
	Port  int
}

TabletNode is the representation of a tablet in the db topology. It can be constructed from a Tablet object, or from an EndPoint.

func (*TabletNode) ShortName

func (tn *TabletNode) ShortName() string

ShortName returns a displayable representation of the host name. If the host is an IP address instead of a name, it is not shortened.

type TabletNodesByType

type TabletNodesByType map[topo.TabletType][]*TabletNode

TabletNodesByType maps tablet types to slices of tablet nodes.

type Topology

type Topology struct {
	Assigned map[string]*KeyspaceNodes // indexed by keyspace name
	Idle     []*TabletNode
	Scrap    []*TabletNode
	Partial  bool
}

Topology is the entire set of tablets in the topology.

func DbTopology

func DbTopology(ctx context.Context, ts topo.Server) (*Topology, error)

DbTopology returns the Topology for the topo server.