net.javacrumbs.shedlock.provider.mongo

Class MongoLockProvider

java.lang.Object

net.javacrumbs.shedlock.provider.mongo.MongoLockProvider

All Implemented Interfaces:

LockProvider

public class MongoLockProvider
extends Object
implements LockProvider

Distributed lock using MongoDB >= 2.6. Requires mongo-java-driver > 3.4.0

It uses a collection that contains documents like this:

 {
    "_id" : "lock name",
    "lockUntil" : ISODate("2017-01-07T16:52:04.071Z"),
    "lockedAt" : ISODate("2017-01-07T16:52:03.932Z"),
    "lockedBy" : "host name"
 }
 

lockedAt and lockedBy are just for troubleshooting and are not read by the code

1. Attempts to insert a new lock record. As an optimization, we keep in-memory track of created lock records. If the record has been inserted, returns lock.
2. We will try to update lock record using filter _id == name AND lock_until <= now
3. If the update succeeded (1 updated document), we have the lock. If the update failed (0 updated documents) somebody else holds the lock
4. When unlocking, lock_until is set to now.

Constructor Summary

Constructors

Constructor and Description
MongoLockProvider(com.mongodb.MongoClient mongo, String databaseName) Uses Mongo to coordinate locks
MongoLockProvider(com.mongodb.MongoClient mongo, String databaseName, String collectionName) Uses Mongo to coordinate locks
MongoLockProvider(com.mongodb.client.MongoCollection<org.bson.Document> collection) Uses Mongo to coordinate locks

Method Summary

Modifier and Type	Method and Description
Optional<SimpleLock>	lock(LockConfiguration lockConfiguration)

Methods inherited from class java.lang.Object

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

Constructor Detail

MongoLockProvider

public MongoLockProvider(com.mongodb.MongoClient mongo,
                         String databaseName)

Uses Mongo to coordinate locks

Parameters:

mongo - Mongo to be used

databaseName - database to be used

MongoLockProvider

public MongoLockProvider(com.mongodb.MongoClient mongo,
                         String databaseName,
                         String collectionName)

Uses Mongo to coordinate locks

Parameters:

mongo - Mongo to be used

databaseName - database to be used

collectionName - collection to store the locks

MongoLockProvider

public MongoLockProvider(com.mongodb.client.MongoCollection<org.bson.Document> collection)

Uses Mongo to coordinate locks

Parameters:

collection - Mongo collection to be used

Method Detail

lock

public Optional<SimpleLock> lock(LockConfiguration lockConfiguration)

Specified by:

lock in interface LockProvider