state

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Published: Sep 14, 2016 License: MPL-2.0 Imports: 12 Imported by: 0

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Constants

This section is empty.

Variables

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var (
	// ErrMissingNode is the error returned when trying an operation
	// which requires a node registration but none exists.
	ErrMissingNode = errors.New("Missing node registration")

	// ErrMissingService is the error we return if trying an
	// operation which requires a service but none exists.
	ErrMissingService = errors.New("Missing service registration")

	// ErrMissingSessionID is returned when a session registration
	// is attempted with an empty session ID.
	ErrMissingSessionID = errors.New("Missing session ID")

	// ErrMissingACLID is returned when an ACL set is called on
	// an ACL with an empty ID.
	ErrMissingACLID = errors.New("Missing ACL ID")

	// ErrMissingQueryID is returned when a Query set is called on
	// a Query with an empty ID.
	ErrMissingQueryID = errors.New("Missing Query ID")
)

Functions

This section is empty.

Types

type Delay

type Delay struct {
	// contains filtered or unexported fields
}

Delay is used to mark certain locks as unacquirable. When a lock is forcefully released (failing health check, destroyed session, etc.), it is subject to the LockDelay impossed by the session. This prevents another session from acquiring the lock for some period of time as a protection against split-brains. This is inspired by the lock-delay in Chubby. Because this relies on wall-time, we cannot assume all peers perceive time as flowing uniformly. This means KVSLock MUST ignore lockDelay, since the lockDelay may have expired on the leader, but not on the follower. Rejecting the lock could result in inconsistencies in the FSMs due to the rate time progresses. Instead, only the opinion of the leader is respected, and the Raft log is never questioned.

func NewDelay

func NewDelay() *Delay

NewDelay returns a new delay manager.

func (*Delay) GetExpiration

func (d *Delay) GetExpiration(key string) time.Time

GetExpiration returns the expiration time of a key lock delay. This must be checked on the leader node, and not in KVSLock due to the variability of clocks.

func (*Delay) SetExpiration

func (d *Delay) SetExpiration(key string, now time.Time, delay time.Duration)

SetExpiration sets the expiration time for the lock delay to the given delay from the given now time.

type DumbWatchManager

type DumbWatchManager struct {
	// contains filtered or unexported fields
}

DumbWatchManager is a wrapper that allows nested code to arm full table watches multiple times but fire them only once. This doesn't have any way to clear the state, and it's not thread-safe, so it should be used once and thrown away inside the context of a single thread.

func NewDumbWatchManager

func NewDumbWatchManager(tableWatches map[string]*FullTableWatch) *DumbWatchManager

NewDumbWatchManager returns a new dumb watch manager.

func (*DumbWatchManager) Arm

func (d *DumbWatchManager) Arm(table string)

Arm arms the given table's watch.

func (*DumbWatchManager) Notify

func (d *DumbWatchManager) Notify()

Notify fires watches for all the armed tables.

type FullTableWatch

type FullTableWatch struct {
	// contains filtered or unexported fields
}

FullTableWatch implements a single notify group for a table.

func NewFullTableWatch

func NewFullTableWatch() *FullTableWatch

NewFullTableWatch returns a new full table watch.

func (*FullTableWatch) Clear

func (w *FullTableWatch) Clear(notifyCh chan struct{})

See Watch.

func (*FullTableWatch) Notify

func (w *FullTableWatch) Notify()

Notify wakes up all the watchers registered for this table.

func (*FullTableWatch) Wait

func (w *FullTableWatch) Wait(notifyCh chan struct{})

See Watch.

type Graveyard

type Graveyard struct {
	// contains filtered or unexported fields
}

Graveyard manages a set of tombstones.

func NewGraveyard

func NewGraveyard(gc *TombstoneGC) *Graveyard

NewGraveyard returns a new graveyard.

func (*Graveyard) DumpTxn

func (g *Graveyard) DumpTxn(tx *memdb.Txn) (memdb.ResultIterator, error)

DumpTxn returns all the tombstones.

func (*Graveyard) GetMaxIndexTxn

func (g *Graveyard) GetMaxIndexTxn(tx *memdb.Txn, prefix string) (uint64, error)

GetMaxIndexTxn returns the highest index tombstone whose key matches the given context, using a prefix match.

func (*Graveyard) InsertTxn

func (g *Graveyard) InsertTxn(tx *memdb.Txn, key string, idx uint64) error

InsertTxn adds a new tombstone.

func (*Graveyard) ReapTxn

func (g *Graveyard) ReapTxn(tx *memdb.Txn, idx uint64) error

ReapTxn cleans out all tombstones whose index values are less than or equal to the given idx. This prevents unbounded storage growth of the tombstones.

func (*Graveyard) RestoreTxn

func (g *Graveyard) RestoreTxn(tx *memdb.Txn, stone *Tombstone) error

RestoreTxn is used when restoring from a snapshot. For general inserts, use InsertTxn.

type IndexEntry

type IndexEntry struct {
	Key   string
	Value uint64
}

IndexEntry keeps a record of the last index per-table.

type MultiWatch

type MultiWatch struct {
	// contains filtered or unexported fields
}

MultiWatch wraps several watches and allows any of them to trigger the caller.

func NewMultiWatch

func NewMultiWatch(watches ...Watch) *MultiWatch

NewMultiWatch returns a new new multi watch over the given set of watches.

func (*MultiWatch) Clear

func (w *MultiWatch) Clear(notifyCh chan struct{})

See Watch.

func (*MultiWatch) Wait

func (w *MultiWatch) Wait(notifyCh chan struct{})

See Watch.

type NotifyGroup

type NotifyGroup struct {
	// contains filtered or unexported fields
}

NotifyGroup is used to allow a simple notification mechanism. Channels can be marked as waiting, and when notify is invoked, all the waiting channels get a message and are cleared from the notify list.

func (*NotifyGroup) Clear

func (n *NotifyGroup) Clear(ch chan struct{})

Clear removes a channel from the notify group

func (*NotifyGroup) Notify

func (n *NotifyGroup) Notify()

Notify will do a non-blocking send to all waiting channels, and clear the notify list

func (*NotifyGroup) Wait

func (n *NotifyGroup) Wait(ch chan struct{})

Wait adds a channel to the notify group

func (*NotifyGroup) WaitCh

func (n *NotifyGroup) WaitCh() chan struct{}

WaitCh allocates a channel that is subscribed to notifications

type PrefixWatch

type PrefixWatch struct {
	// contains filtered or unexported fields
}

PrefixWatch provides a Watch-compatible interface for a PrefixWatchManager, bound to a specific prefix.

func (*PrefixWatch) Clear added in v0.6.4

func (w *PrefixWatch) Clear(notifyCh chan struct{})

Clear deregisters the given channel from the the notify group for our prefix.

func (*PrefixWatch) Wait added in v0.6.4

func (w *PrefixWatch) Wait(notifyCh chan struct{})

Wait registers the given channel with the notify group for our prefix.

type PrefixWatchManager added in v0.6.4

type PrefixWatchManager struct {
	// contains filtered or unexported fields
}

PrefixWatchManager maintains a notify group for each prefix, allowing for much more fine-grained watches.

func NewPrefixWatchManager added in v0.6.4

func NewPrefixWatchManager() *PrefixWatchManager

NewPrefixWatchManager returns a new prefix watch manager.

func (*PrefixWatchManager) Clear added in v0.6.4

func (w *PrefixWatchManager) Clear(prefix string, notifyCh chan struct{})

Clear deregisters the given channel from the notify group for a prefix (if one exists).

func (*PrefixWatchManager) NewPrefixWatch added in v0.6.4

func (w *PrefixWatchManager) NewPrefixWatch(prefix string) Watch

NewPrefixWatch returns a Watch-compatible interface for watching the given prefix.

func (*PrefixWatchManager) Notify added in v0.6.4

func (w *PrefixWatchManager) Notify(prefix string, subtree bool)

Notify wakes up all the watchers associated with the given prefix. If subtree is true then we will also notify all the tree under the prefix, such as when a key is being deleted.

func (*PrefixWatchManager) Wait added in v0.6.4

func (w *PrefixWatchManager) Wait(prefix string, notifyCh chan struct{})

Wait registers the given channel on a prefix.

type PreparedQueryIndex added in v0.6.4

type PreparedQueryIndex struct {
}

PreparedQueryIndex is a custom memdb indexer used to manage index prepared query templates. None of the built-in indexers do what we need, and our use case is pretty specific so it's better to put the logic here.

func (*PreparedQueryIndex) FromArgs added in v0.6.4

func (p *PreparedQueryIndex) FromArgs(args ...interface{}) ([]byte, error)

FromArgs is used when querying for an exact match. Since we don't add any suffix we can just call the prefix version.

func (*PreparedQueryIndex) FromObject added in v0.6.4

func (*PreparedQueryIndex) FromObject(obj interface{}) (bool, []byte, error)

FromObject is used to compute the index key when inserting or updating an object.

func (*PreparedQueryIndex) PrefixFromArgs added in v0.6.4

func (*PreparedQueryIndex) PrefixFromArgs(args ...interface{}) ([]byte, error)

PrefixFromArgs is used when doing a prefix scan for an object.

type StateRestore

type StateRestore struct {
	// contains filtered or unexported fields
}

StateRestore is used to efficiently manage restoring a large amount of data to a state store.

func (*StateRestore) ACL

func (s *StateRestore) ACL(acl *structs.ACL) error

ACL is used when restoring from a snapshot. For general inserts, use ACLSet.

func (*StateRestore) Abort

func (s *StateRestore) Abort()

Abort abandons the changes made by a restore. This or Commit should always be called.

func (*StateRestore) Commit

func (s *StateRestore) Commit()

Commit commits the changes made by a restore. This or Abort should always be called.

func (*StateRestore) Coordinates

func (s *StateRestore) Coordinates(idx uint64, updates structs.Coordinates) error

Coordinates is used when restoring from a snapshot. For general inserts, use CoordinateBatchUpdate. We do less vetting of the updates here because they already got checked on the way in during a batch update.

func (*StateRestore) KVS

func (s *StateRestore) KVS(entry *structs.DirEntry) error

KVS is used when restoring from a snapshot. Use KVSSet for general inserts.

func (*StateRestore) PreparedQuery

func (s *StateRestore) PreparedQuery(query *structs.PreparedQuery) error

PrepparedQuery is used when restoring from a snapshot. For general inserts, use PreparedQuerySet.

func (*StateRestore) Registration

func (s *StateRestore) Registration(idx uint64, req *structs.RegisterRequest) error

Registration is used to make sure a node, service, and check registration is performed within a single transaction to avoid race conditions on state updates.

func (*StateRestore) Session

func (s *StateRestore) Session(sess *structs.Session) error

Session is used when restoring from a snapshot. For general inserts, use SessionCreate.

func (*StateRestore) Tombstone

func (s *StateRestore) Tombstone(stone *Tombstone) error

Tombstone is used when restoring from a snapshot. For general inserts, use Graveyard.InsertTxn.

type StateSnapshot

type StateSnapshot struct {
	// contains filtered or unexported fields
}

StateSnapshot is used to provide a point-in-time snapshot. It works by starting a read transaction against the whole state store.

func (*StateSnapshot) ACLs

func (s *StateSnapshot) ACLs() (memdb.ResultIterator, error)

ACLs is used to pull all the ACLs from the snapshot.

func (*StateSnapshot) Checks

func (s *StateSnapshot) Checks(node string) (memdb.ResultIterator, error)

Checks is used to pull the full list of checks for a given node for use during snapshots.

func (*StateSnapshot) Close

func (s *StateSnapshot) Close()

Close performs cleanup of a state snapshot.

func (*StateSnapshot) Coordinates

func (s *StateSnapshot) Coordinates() (memdb.ResultIterator, error)

Coordinates is used to pull all the coordinates from the snapshot.

func (*StateSnapshot) KVs

func (s *StateSnapshot) KVs() (memdb.ResultIterator, error)

KVs is used to pull the full list of KVS entries for use during snapshots.

func (*StateSnapshot) LastIndex

func (s *StateSnapshot) LastIndex() uint64

LastIndex returns that last index that affects the snapshotted data.

func (*StateSnapshot) Nodes

func (s *StateSnapshot) Nodes() (memdb.ResultIterator, error)

Nodes is used to pull the full list of nodes for use during snapshots.

func (*StateSnapshot) PreparedQueries

func (s *StateSnapshot) PreparedQueries() (structs.PreparedQueries, error)

PreparedQueries is used to pull all the prepared queries from the snapshot.

func (*StateSnapshot) Services

func (s *StateSnapshot) Services(node string) (memdb.ResultIterator, error)

Services is used to pull the full list of services for a given node for use during snapshots.

func (*StateSnapshot) Sessions

func (s *StateSnapshot) Sessions() (memdb.ResultIterator, error)

Sessions is used to pull the full list of sessions for use during snapshots.

func (*StateSnapshot) Tombstones

func (s *StateSnapshot) Tombstones() (memdb.ResultIterator, error)

Tombstones is used to pull all the tombstones from the graveyard.

type StateStore

type StateStore struct {
	// contains filtered or unexported fields
}

StateStore is where we store all of Consul's state, including records of node registrations, services, checks, key/value pairs and more. The DB is entirely in-memory and is constructed from the Raft log through the FSM.

func NewStateStore

func NewStateStore(gc *TombstoneGC) (*StateStore, error)

NewStateStore creates a new in-memory state storage layer.

func (*StateStore) ACLDelete

func (s *StateStore) ACLDelete(idx uint64, aclID string) error

ACLDelete is used to remove an existing ACL from the state store. If the ACL does not exist this is a no-op and no error is returned.

func (*StateStore) ACLGet

func (s *StateStore) ACLGet(aclID string) (uint64, *structs.ACL, error)

ACLGet is used to look up an existing ACL by ID.

func (*StateStore) ACLList

func (s *StateStore) ACLList() (uint64, structs.ACLs, error)

ACLList is used to list out all of the ACLs in the state store.

func (*StateStore) ACLSet

func (s *StateStore) ACLSet(idx uint64, acl *structs.ACL) error

ACLSet is used to insert an ACL rule into the state store.

func (*StateStore) CheckServiceNodes

func (s *StateStore) CheckServiceNodes(serviceName string) (uint64, structs.CheckServiceNodes, error)

CheckServiceNodes is used to query all nodes and checks for a given service The results are compounded into a CheckServiceNodes, and the index returned is the maximum index observed over any node, check, or service in the result set.

func (*StateStore) CheckServiceTagNodes

func (s *StateStore) CheckServiceTagNodes(serviceName, tag string) (uint64, structs.CheckServiceNodes, error)

CheckServiceTagNodes is used to query all nodes and checks for a given service, filtering out services that don't contain the given tag. The results are compounded into a CheckServiceNodes, and the index returned is the maximum index observed over any node, check, or service in the result set.

func (*StateStore) ChecksInState

func (s *StateStore) ChecksInState(state string) (uint64, structs.HealthChecks, error)

ChecksInState is used to query the state store for all checks which are in the provided state.

func (*StateStore) CoordinateBatchUpdate

func (s *StateStore) CoordinateBatchUpdate(idx uint64, updates structs.Coordinates) error

CoordinateBatchUpdate processes a batch of coordinate updates and applies them in a single transaction.

func (*StateStore) CoordinateGetRaw

func (s *StateStore) CoordinateGetRaw(node string) (*coordinate.Coordinate, error)

CoordinateGetRaw queries for the coordinate of the given node. This is an unusual state store method because it just returns the raw coordinate or nil, none of the Raft or node information is returned. This hits the 90% internal-to-Consul use case for this data, and this isn't exposed via an endpoint, so it doesn't matter that the Raft info isn't available.

func (*StateStore) Coordinates

func (s *StateStore) Coordinates() (uint64, structs.Coordinates, error)

Coordinates queries for all nodes with coordinates.

func (*StateStore) DeleteCheck

func (s *StateStore) DeleteCheck(idx uint64, node string, checkID types.CheckID) error

DeleteCheck is used to delete a health check registration.

func (*StateStore) DeleteNode

func (s *StateStore) DeleteNode(idx uint64, nodeID string) error

DeleteNode is used to delete a given node by its ID.

func (*StateStore) DeleteService

func (s *StateStore) DeleteService(idx uint64, nodeID, serviceID string) error

DeleteService is used to delete a given service associated with a node.

func (*StateStore) EnsureCheck

func (s *StateStore) EnsureCheck(idx uint64, hc *structs.HealthCheck) error

EnsureCheck is used to store a check registration in the db.

func (*StateStore) EnsureNode

func (s *StateStore) EnsureNode(idx uint64, node *structs.Node) error

EnsureNode is used to upsert node registration or modification.

func (*StateStore) EnsureRegistration

func (s *StateStore) EnsureRegistration(idx uint64, req *structs.RegisterRequest) error

EnsureRegistration is used to make sure a node, service, and check registration is performed within a single transaction to avoid race conditions on state updates.

func (*StateStore) EnsureService

func (s *StateStore) EnsureService(idx uint64, node string, svc *structs.NodeService) error

EnsureService is called to upsert creation of a given NodeService.

func (*StateStore) GetKVSWatch

func (s *StateStore) GetKVSWatch(prefix string) Watch

GetKVSWatch returns a watch for the given prefix in the key value store.

func (*StateStore) GetNode

func (s *StateStore) GetNode(id string) (uint64, *structs.Node, error)

GetNode is used to retrieve a node registration by node ID.

func (*StateStore) GetQueryWatch

func (s *StateStore) GetQueryWatch(method string) Watch

GetQueryWatch returns a watch for the given query method. This is used for all methods except for KV; you should call GetKVSWatch instead. This will panic if the method is unknown.

func (*StateStore) KVSDelete

func (s *StateStore) KVSDelete(idx uint64, key string) error

KVSDelete is used to perform a shallow delete on a single key in the the state store.

func (*StateStore) KVSDeleteCAS

func (s *StateStore) KVSDeleteCAS(idx, cidx uint64, key string) (bool, error)

KVSDeleteCAS is used to try doing a KV delete operation with a given raft index. If the CAS index specified is not equal to the last observed index for the given key, then the call is a noop, otherwise a normal KV delete is invoked.

func (*StateStore) KVSDeleteTree

func (s *StateStore) KVSDeleteTree(idx uint64, prefix string) error

KVSDeleteTree is used to do a recursive delete on a key prefix in the state store. If any keys are modified, the last index is set, otherwise this is a no-op.

func (*StateStore) KVSGet

func (s *StateStore) KVSGet(key string) (uint64, *structs.DirEntry, error)

KVSGet is used to retrieve a key/value pair from the state store.

func (*StateStore) KVSList

func (s *StateStore) KVSList(prefix string) (uint64, structs.DirEntries, error)

KVSList is used to list out all keys under a given prefix. If the prefix is left empty, all keys in the KVS will be returned. The returned is the max index of the returned kvs entries or applicable tombstones, or else it's the full table indexes for kvs and tombstones.

func (*StateStore) KVSListKeys

func (s *StateStore) KVSListKeys(prefix, sep string) (uint64, []string, error)

KVSListKeys is used to query the KV store for keys matching the given prefix. An optional separator may be specified, which can be used to slice off a part of the response so that only a subset of the prefix is returned. In this mode, the keys which are omitted are still counted in the returned index.

func (*StateStore) KVSLock

func (s *StateStore) KVSLock(idx uint64, entry *structs.DirEntry) (bool, error)

KVSLock is similar to KVSSet but only performs the set if the lock can be acquired.

func (*StateStore) KVSLockDelay

func (s *StateStore) KVSLockDelay(key string) time.Time

KVSLockDelay returns the expiration time for any lock delay associated with the given key.

func (*StateStore) KVSSet

func (s *StateStore) KVSSet(idx uint64, entry *structs.DirEntry) error

KVSSet is used to store a key/value pair.

func (*StateStore) KVSSetCAS

func (s *StateStore) KVSSetCAS(idx uint64, entry *structs.DirEntry) (bool, error)

KVSSetCAS is used to do a check-and-set operation on a KV entry. The ModifyIndex in the provided entry is used to determine if we should write the entry to the state store or bail. Returns a bool indicating if a write happened and any error.

func (*StateStore) KVSUnlock

func (s *StateStore) KVSUnlock(idx uint64, entry *structs.DirEntry) (bool, error)

KVSUnlock is similar to KVSSet but only performs the set if the lock can be unlocked (the key must already exist and be locked).

func (*StateStore) NodeChecks

func (s *StateStore) NodeChecks(nodeID string) (uint64, structs.HealthChecks, error)

NodeChecks is used to retrieve checks associated with the given node from the state store.

func (*StateStore) NodeDump

func (s *StateStore) NodeDump() (uint64, structs.NodeDump, error)

NodeDump is used to generate a dump of all nodes. This call is expensive as it has to query every node, service, and check. The response can also be quite large since there is currently no filtering applied.

func (*StateStore) NodeInfo

func (s *StateStore) NodeInfo(node string) (uint64, structs.NodeDump, error)

NodeInfo is used to generate a dump of a single node. The dump includes all services and checks which are registered against the node.

func (*StateStore) NodeServices

func (s *StateStore) NodeServices(nodeID string) (uint64, *structs.NodeServices, error)

NodeServices is used to query service registrations by node ID.

func (*StateStore) NodeSessions

func (s *StateStore) NodeSessions(nodeID string) (uint64, structs.Sessions, error)

NodeSessions returns a set of active sessions associated with the given node ID. The returned index is the highest index seen from the result set.

func (*StateStore) Nodes

func (s *StateStore) Nodes() (uint64, structs.Nodes, error)

Nodes is used to return all of the known nodes.

func (*StateStore) PreparedQueryDelete

func (s *StateStore) PreparedQueryDelete(idx uint64, queryID string) error

PreparedQueryDelete deletes the given query by ID.

func (*StateStore) PreparedQueryGet

func (s *StateStore) PreparedQueryGet(queryID string) (uint64, *structs.PreparedQuery, error)

PreparedQueryGet returns the given prepared query by ID.

func (*StateStore) PreparedQueryList

func (s *StateStore) PreparedQueryList() (uint64, structs.PreparedQueries, error)

PreparedQueryList returns all the prepared queries.

func (*StateStore) PreparedQueryResolve added in v0.6.4

func (s *StateStore) PreparedQueryResolve(queryIDOrName string) (uint64, *structs.PreparedQuery, error)

PreparedQueryResolve returns the given prepared query by looking up an ID or Name. If the query was looked up by name and it's a template, then the template will be rendered before it is returned.

func (*StateStore) PreparedQuerySet

func (s *StateStore) PreparedQuerySet(idx uint64, query *structs.PreparedQuery) error

PreparedQuerySet is used to create or update a prepared query.

func (*StateStore) ReapTombstones

func (s *StateStore) ReapTombstones(index uint64) error

ReapTombstones is used to delete all the tombstones with an index less than or equal to the given index. This is used to prevent unbounded storage growth of the tombstones.

func (*StateStore) Restore

func (s *StateStore) Restore() *StateRestore

Restore is used to efficiently manage restoring a large amount of data into the state store. It works by doing all the restores inside of a single transaction.

func (*StateStore) ServiceChecks

func (s *StateStore) ServiceChecks(serviceName string) (uint64, structs.HealthChecks, error)

ServiceChecks is used to get all checks associated with a given service ID. The query is performed against a service _name_ instead of a service ID.

func (*StateStore) ServiceNodes

func (s *StateStore) ServiceNodes(serviceName string) (uint64, structs.ServiceNodes, error)

ServiceNodes returns the nodes associated with a given service name.

func (*StateStore) ServiceTagNodes

func (s *StateStore) ServiceTagNodes(service, tag string) (uint64, structs.ServiceNodes, error)

ServiceTagNodes returns the nodes associated with a given service, filtering out services that don't contain the given tag.

func (*StateStore) Services

func (s *StateStore) Services() (uint64, structs.Services, error)

Services returns all services along with a list of associated tags.

func (*StateStore) SessionCreate

func (s *StateStore) SessionCreate(idx uint64, sess *structs.Session) error

SessionCreate is used to register a new session in the state store.

func (*StateStore) SessionDestroy

func (s *StateStore) SessionDestroy(idx uint64, sessionID string) error

SessionDestroy is used to remove an active session. This will implicitly invalidate the session and invoke the specified session destroy behavior.

func (*StateStore) SessionGet

func (s *StateStore) SessionGet(sessionID string) (uint64, *structs.Session, error)

SessionGet is used to retrieve an active session from the state store.

func (*StateStore) SessionList

func (s *StateStore) SessionList() (uint64, structs.Sessions, error)

SessionList returns a slice containing all of the active sessions.

func (*StateStore) Snapshot

func (s *StateStore) Snapshot() *StateSnapshot

Snapshot is used to create a point-in-time snapshot of the entire db.

func (*StateStore) TxnRO added in v0.7.0

TxnRO runs the given operations inside a single read transaction in the state store. You must verify outside this function that no write operations are present, otherwise you'll get an error from the state store.

func (*StateStore) TxnRW added in v0.7.0

TxnRW tries to run the given operations all inside a single transaction. If any of the operations fail, the entire transaction will be rolled back. This is done in a full write transaction on the state store, so reads and writes are possible

type Tombstone

type Tombstone struct {
	Key   string
	Index uint64
}

Tombstone is the internal type used to track tombstones.

type TombstoneGC

type TombstoneGC struct {
	// contains filtered or unexported fields
}

TombstoneGC is used to track creation of tombstones so that they can be garbage collected after their TTL expires. The tombstones allow queries to provide monotonic index values within the TTL window. The GC is used to prevent monotonic growth in storage usage. This is a trade off between the length of the TTL and the storage overhead.

In practice, this is required to fix the issue of delete visibility. When data is deleted from the KV store, the "latest" row can go backwards if the newest row is removed. The tombstones provide a way to ensure time doesn't move backwards within some interval.

func NewTombstoneGC

func NewTombstoneGC(ttl, granularity time.Duration) (*TombstoneGC, error)

NewTombstoneGC is used to construct a new TombstoneGC given a TTL for tombstones and a tracking granularity. Longer TTLs ensure correct behavior for more time, but use more storage. A shorter granularity increases the number of Raft transactions and reduce how far past the TTL we perform GC.

func (*TombstoneGC) ExpireCh

func (t *TombstoneGC) ExpireCh() <-chan uint64

ExpireCh is used to return a channel that streams the next index that should be expired

func (*TombstoneGC) Hint

func (t *TombstoneGC) Hint(index uint64)

Hint is used to indicate that keys at the given index have been deleted, and that their GC should be scheduled.

func (*TombstoneGC) PendingExpiration

func (t *TombstoneGC) PendingExpiration() bool

PendingExpiration is used to check if any expirations are pending

func (*TombstoneGC) SetEnabled

func (t *TombstoneGC) SetEnabled(enabled bool)

SetEnabled is used to control if the tombstone GC is enabled. Should only be enabled by the leader node.

type Watch

type Watch interface {
	// Wait registers the given channel and calls it back when the watch
	// fires.
	Wait(notifyCh chan struct{})

	// Clear deregisters the given channel.
	Clear(notifyCh chan struct{})
}

Watch is the external interface that's common to all the different flavors.

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