README.md

Scalalock

Distributed lock library in scala. based on mongodb (using reactivemongo or mongo-scala-driver)

consists of 3 modules:

• scalalock-api - contains the api and the locking logic
• scalalock-mongo - an api implementation using mongodb as the lock persistence store. implementation is dependant on mongo-scala-driver.
• scalalock-reactivemongo - an alternative api implementation using reactivemongo as the mongodb driver. implementation is dependant on reactivemongo.

Usage

1. Add dependencies to build.sbt:

• Option A - if you're using mongo-scala-driver

  libraryDependencies ++= Seq(
    "com.weirddev" %% "scalalock-api" % "1.0.6",
    "com.weirddev" %% "scalalock-mongo" % "1.0.6"
  )

• Option B - if you're using reactivemongo

  libraryDependencies ++= Seq(
    "com.weirddev" %% "scalalock-api" % "1.0.6",
    "com.weirddev" %% "scalalock-reactivemongo" % "1.1.0" //for reactivemongo 1.*

// "com.weirddev" %% "scalalock-reactivemongo" % "1.0.6" //for reactivemongo 0.* ) ```

2. wrap the block that should be synchronized across all nodes in cluster with Lock#acquire() method call

   • For scalalock-mongo (based on mongo-scala-driver)

   import com.mongodb.ConnectionString
   import com.weirddev.scalalock.mongo.MongoDistributedLock
   import org.mongodb.scala.{MongoClient, MongoClientSettings, MongoDatabase}
   import scala.concurrent.Future
   import scala.concurrent.duration._
   
   protected val db: MongoDatabase = MongoClient(MongoClientSettings.builder()
       .applyConnectionString(new ConnectionString("mongodb://localhost:27017"))
       .build()).getDatabase("test")
   
   val distLock:Lock = new MongoDistributedLock(db)
   
   distLock.acquire("some_task_id", 10 minutes){
     Future{
       println("this block needs to execute in isolation across all application nodes in cluster")
       Thread.sleep(5000)
       "Task Completed"
     }
   }

   • Alternatively, using scalalock-reactivemongo (based on org.reactivemongo)

   import com.weirddev.scalalock.reactivemongo.ReactiveMongoDistributedLock
   import reactivemongo.api.{DefaultDB, MongoConnection, MongoDriver}
   import scala.concurrent.ExecutionContext.Implicits.global
   import scala.concurrent.Future
   import scala.concurrent.duration._
   
   private val mongoUri: String = "mongodb://localhost:27017/test"
     val driver = new MongoDriver
     val database: Future[DefaultDB] = for {
       uri <- Future.fromTry(MongoConnection.parseURI(mongoUri))
       con = driver.connection(uri)
       dn <- Future(uri.db.get)
       db <- con.database(dn)
     } yield db
   
     val distLock = new ReactiveMongoDistributedLock(database)
   
   distLock.acquire("some_task_id", 10 minutes){
     Future{
       println("this block needs to execute in isolation across all application nodes in cluster")
       Thread.sleep(5000)
       "Task Completed"
     }
   }

   • A simpler alternative using scalalock-reactivemongo in Play! Framework (add a dependency on reactivemongo play, i.e. "org.reactivemongo" %% "play2-reactivemongo" % "0.16.5-play26" )

   import com.weirddev.scalalock.reactivemongo.ReactiveMongoDistributedLock
   import scala.concurrent.{ExecutionContext, Future}
   import scala.concurrent.duration._
   import javax.inject.Inject
   import play.modules.reactivemongo.ReactiveMongoApi
   
   class MyRepository @Inject()(override val reactiveMongoApi: ReactiveMongoApi)(implicit val ec: ExecutionContext){
     val distLock = new ReactiveMongoDistributedLock(reactiveMongoApi.database)
   
     distLock.acquire("some_task_id", 10 minutes){
       Future{
         println("this block needs to execute in isolation across all application nodes in cluster")
         Thread.sleep(5000)
         "Task Completed"
       }
     }
   }

3. If you want to use the lock to synchronize task execution globally in a cluster and mandating a minimal interval - pass the releaseLockWhenDone as false. This will keep the lock state as LOCKED even after task completion. Effectively keeping the lock until expiration - as set by the expire param. example:

     val result = mongoDistLock.acquire(resourceId =  "test_task", expire = 30 minutes,releaseLockWhenDone = false){
         println("After this block finishes to execute, the lock will retain for 30 minutes before any other task using resource id - test_task - could run again")
         Thread.sleep(5000)
          "Done"
     }

   For other usage scenarios, review the integrative test code

Contributing/Developing

Welcomed :) - Please refer to CONTRIBUTING.md file.

License

Copyright (c) 2016 - 2024 WeirdDev. Licensed for free usage under the terms and conditions of Apache V2 - Apache V2 License.