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In Memory Distributed Lock

The in-memory connector was created for local development and testing purposes.

Usage

Add dependencies to build.gradle.kts:

dependencies {
    implementation("com.coditory.sherlock:sherlock-inmem:0.4.19")
}

dependencies {
    implementation("com.coditory.sherlock:sherlock-inmem-coroutine:0.4.19")
    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:$versions.coroutines")
}

dependencies {
    implementation("com.coditory.sherlock:sherlock-inmem-reactor:0.4.19")
}

dependencies {
    implementation("com.coditory.sherlock:sherlock-inmem-rxjava:0.4.19")
}

Create sherlock instance and distributed lock:

import com.coditory.sherlock.DistributedLock;
import com.coditory.sherlock.Sherlock;
import com.coditory.sherlock.inmem.InMemorySherlock;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class InMemSyncLockSample {
    private static final Logger logger = LoggerFactory.getLogger(InMemSyncLockSample.class);

    public static void main(String[] args) {
        Sherlock sherlock = InMemorySherlock.create();
        DistributedLock lock = sherlock.createLock("sample-lock");
        lock.runLocked(() -> logger.info("Lock acquired!"));
    }
}

import com.coditory.sherlock.inmem.coroutines.InMemorySherlock
import kotlinx.coroutines.runBlocking
import org.slf4j.Logger
import org.slf4j.LoggerFactory

object InMemKtLockSample {
    private val logger: Logger = LoggerFactory.getLogger(this.javaClass)

    private suspend fun sample() {
        val sherlock = InMemorySherlock.create()
        val lock = sherlock.createLock("sample-lock")
        lock.runLocked {
            logger.info("Lock acquired!")
        }
    }

    @JvmStatic
    fun main(args: Array<String>) {
        runBlocking { sample() }
    }
}

import com.coditory.sherlock.inmem.reactor.InMemorySherlock;
import com.coditory.sherlock.reactor.DistributedLock;
import com.coditory.sherlock.reactor.Sherlock;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import reactor.core.publisher.Mono;

public class InMemReactorLockSample {
    private static final Logger logger = LoggerFactory.getLogger(InMemReactorLockSample.class);

    public static void main(String[] args) {
        Sherlock sherlock = InMemorySherlock.create();
        DistributedLock lock = sherlock.createLock("sample-lock");
        lock.runLocked(Mono.fromCallable(() -> {
            logger.info("Lock acquired!");
            return true;
        })).block();
    }
}

import com.coditory.sherlock.inmem.rxjava.InMemorySherlock;
import com.coditory.sherlock.rxjava.DistributedLock;
import com.coditory.sherlock.rxjava.Sherlock;
import io.reactivex.rxjava3.core.Single;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class InMemRxLockSample {
    private static final Logger logger = LoggerFactory.getLogger(InMemRxLockSample.class);

    public static void main(String[] args) {
        Sherlock sherlock = InMemorySherlock.create();
        DistributedLock lock = sherlock.createLock("sample-lock");
        lock.runLocked(Single.fromCallable(() -> {
            logger.info("Lock acquired!");
            return true;
        })).blockingGet();
    }
}

Learn more

See full source code example on Github.

Configuration

Configuration is available via sherlock builder:

MongoSherlock.builder()
    .withClock(Clock.systemUTC())
    .withLockDuration(Duration.ofMinutes(5))
    .withOwnerIdPolicy(OwnerIdPolicy.uniqueOwnerId())
    .withSharedStorage()
    .build();

MongoSherlock.builder()
    .withClock(Clock.systemUTC())
    .withLockDuration(Duration.ofMinutes(5))
    .withOwnerIdPolicy(OwnerIdPolicy.uniqueOwnerId())
    .withSharedStorage()
    .build()

MongoSherlock.builder()
    .withClock(Clock.systemUTC())
    .withLockDuration(Duration.ofMinutes(5))
    .withOwnerIdPolicy(OwnerIdPolicy.uniqueOwnerId())
    .withSharedStorage()
    .build();

MongoSherlock.builder()
    .withClock(Clock.systemUTC())
    .withLockDuration(Duration.ofMinutes(5))
    .withOwnerIdPolicy(OwnerIdPolicy.uniqueOwnerId())
    .withSharedStorage()
    .build();

Parameters:

  • clock (default: Clock.systemUTC()) - used to generate acquisition and expiration timestamps.
  • lockDuration (default: Duration.ofMinutes(5)) - a default lock expiration time. If lock is not released and expiration time passes, the lock is treated as released.
  • ownerIdPolicy (default: uniqueOwnerId()) - used to generate lock owner id. It's executed once for every lock, during lock creation. There are different policies available for generating lock ownerIds.
  • sharedStorage (default: no shared storage) - use shared storage for all in-mem locks.