distributed-locking

• Implementing distributed locking for scheduled jobs
• Migrating from legacy locking mechanisms
• Choosing between PostgreSQL and Redis locking
• Migrating from Fabric8 leader election
• Migrating from incubated in-repo libraries

Sections

• [When to use this skill](#when-to-use-this-skill) (L24-L31)
• [Quick Start](#quick-start) (L54-L96)
• [Implementation Options](#implementation-options) (L97-L107)
• [Common Patterns](#common-patterns) (L108-L130)
• [References](#references) (L131-L139)
• [Related Rules](#related-rules) (L140-L143)
• [Related Skills](#related-skills) (L144-L149)

Available Resources

📚 references/ - Detailed documentation

• [lock patterns](references/lock-patterns.md)
• [migration workflow](references/migration-workflow.md)
• [redis integration](references/redis-integration.md)
• [troubleshooting](references/troubleshooting.md)

---

1. Add Dependencies (PostgreSQL)

```toml

# gradle/libs.versions.toml

[versions]

distributed-locking-api = "2.0.0"

distributed-locking-postgres-jooq = "2.0.0"

[libraries]

distributed-locking-api = { module = "com.bitso.commons:distributed-locking-api", version.ref = "distributed-locking-api" }

distributed-locking-postgres-jooq = { module = "com.bitso.commons:distributed-locking-postgres-jooq", version.ref = "distributed-locking-postgres-jooq" }

```

2. Create Configuration Bean

```java

@Configuration

public class DistributedLockConfiguration {

@Bean

DistributedLockManager distributedLockManager(

@Qualifier("write-dslcontext") DSLContext dslContext) {

return new JooqPostgresSessionDistributedLockManager(dslContext);

}

}

```

3. Use in Scheduled Jobs

```java

@Scheduled(cron = "${job.cron:-}", zone = "UTC")

public void scheduledJob() {

try (var lock = distributedLockManager.tryLock("job-lock")) {

if (!lock.acquired()) {

log.info("Job already running on another instance");

return;

}

doWork();

}

}

```

RFC-44 supports two valid locking implementations:

| Implementation | When to Use |

|----------------|-------------|

| PostgreSQL Advisory Locks (Default) | Services with PostgreSQL available |

| Redis Locking (Allowed) | Services without PostgreSQL, or with justified Redis use case |

> Important: Redis-based locking is NOT deprecated. It is explicitly supported per RFC-44.

Try-with-resources Pattern

```java

try (var lock = distributedLockManager.tryLock("lock-key")) {

if (!lock.acquired()) {

return;

}

executeTask();

}

```

Vavr Pattern

```java

Try.withResources(() -> distributedLockManager.tryLock("lock-key"))

.of(lock -> Option.of(lock)

.filter(DistributedLock::acquired)

.onEmpty(() -> log.info("Lock not acquired"))

.peek(l -> doWork()));

```

| Reference | Description |

|-----------|-------------|

| [references/migration-workflow.md](references/migration-workflow.md) | Step-by-step migration guide |

| [references/lock-patterns.md](references/lock-patterns.md) | RFC-44 lock patterns |

| [references/redis-integration.md](references/redis-integration.md) | Redis-based locking setup |

| [references/troubleshooting.md](references/troubleshooting.md) | Common issues and solutions |

• .cursor/rules/java-distributed-locking-rfc44.mdc - Full RFC-44 reference

| Skill | Purpose |

|-------|---------|

| [gradle-standards](../gradle-standards/SKILL.md) | Dependency configuration |

| [java-testing](../java-testing/SKILL.md) | Testing lock mechanisms |