org.graylog2.cluster.lock

Class MongoLockService

java.lang.Object

org.graylog2.cluster.lock.MongoLockService

All Implemented Interfaces:

LockService

@Singleton
public class MongoLockService
extends Object
implements LockService

Lock service implementation using MongoDB to maintain locks. Unless a lock is kept alive by periodically re-requesting the same lock, it will eventually expire. Lock expiry is handled by MongoDB internally. We set lock expiry to 60 seconds, but in practice it may take up to ~2 minutes until a lock really expires.

Field Summary

Fields

Modifier and Type	Field and Description
static String	COLLECTION_NAME
static Duration	MIN_LOCK_TTL

Constructor Summary

Constructors

Constructor and Description
MongoLockService(NodeId nodeId, MongoConnection mongoConnection, Duration leaderElectionLockTTL)

Method Summary

Modifier and Type	Method and Description
Optional<Lock>	lock(String resource) Request a lock.
Optional<Lock>	unlock(String resource)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

COLLECTION_NAME

public static final String COLLECTION_NAME

See Also:

Constant Field Values

MIN_LOCK_TTL

public static final Duration MIN_LOCK_TTL

Constructor Detail

MongoLockService

@Inject
public MongoLockService(NodeId nodeId,
                                MongoConnection mongoConnection,
                                @Named(value="lock_service_lock_ttl")
                                Duration leaderElectionLockTTL)

Method Detail

lock

public Optional<Lock> lock(@Nonnull
                           String resource)

Request a lock. If a lock already exists, the lock expiry time will be extended.

Specified by:

lock in interface LockService

Parameters:

resource - Unique identifier for the resource that should be guarded by this lock.

Returns:

A Lock object, if a lock was obtained. An empty Optional, if no lock could be acquired.

unlock

public Optional<Lock> unlock(@Nonnull
                             String resource)

Specified by:

unlock in interface LockService