net.javacrumbs.shedlock.provider.dynamodb

Class DynamoDBLockProvider

java.lang.Object

net.javacrumbs.shedlock.provider.dynamodb.DynamoDBLockProvider

All Implemented Interfaces:

LockProvider

public class DynamoDBLockProvider
extends Object
implements LockProvider

Distributed lock using DynamoDB. Depends on aws-java-sdk-dynamodb.

It uses a table with the following structure:

 {
    "_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.
2. We will try to update lock record using filter _id == :name AND lock_until <= :now.
3. If the update succeeded, we have the lock. If the update failed (condition check exception) somebody else holds the lock.
4. When unlocking, lock_until is set to now or lockAtLeastUntil whichever is later.

Constructor Summary

Constructors

Constructor and Description
DynamoDBLockProvider(com.amazonaws.services.dynamodbv2.document.Table table) Uses DynamoDB 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

DynamoDBLockProvider

public DynamoDBLockProvider(com.amazonaws.services.dynamodbv2.document.Table table)

Uses DynamoDB to coordinate locks

Parameters:

table - existing DynamoDB table to be used

Method Detail

lock

public Optional<SimpleLock> lock(LockConfiguration lockConfiguration)

Specified by:

lock in interface LockProvider