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

Method Summary

Modifier and Type	Method and Description
@NotNull Optional<SimpleLock>	lock(@NotNull 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(@NotNull
                         @NotNull com.mongodb.MongoClient mongo,
                         @NotNull
                         @NotNull String databaseName)

Uses Mongo to coordinate locks

Parameters:

mongo - Mongo to be used

databaseName - database to be used

MongoLockProvider

public MongoLockProvider(@NotNull
                         @NotNull com.mongodb.MongoClient mongo,
                         @NotNull
                         @NotNull String databaseName,
                         @NotNull
                         @NotNull 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(@NotNull
                         @NotNull com.mongodb.client.MongoCollection<org.bson.Document> collection)

Uses Mongo to coordinate locks

Parameters:

collection - Mongo collection to be used

Method Detail

lock

@NotNull
public @NotNull Optional<SimpleLock> lock(@NotNull
                                                   @NotNull LockConfiguration lockConfiguration)

Specified by:

lock in interface LockProvider