Guide to Using tldb Distributed Locks with Go and Java

Distributed locks are a crucial tool in distributed systems, and tldb offers a simple, reliable lock service that mimics object locks in a program. The service can be accessed via various third‑party systems such as Redis, MQ, databases, or Zookeeper.

tldb Distributed Lock Usage Methods

lock : a blocking request for a lock.

trylock : attempts to acquire a lock; returns immediately with success or failure.

unlock : releases a previously acquired lock.

Lock (string, int) Method

The lock("abc", 3) method takes two parameters: the lock name (e.g., "abc" ) and the maximum holding time in seconds. If the lock is not released within the specified time, the server forcibly releases it.

UnLock (string) Method

After a lock is obtained, the server returns a key. The client must call UnLock(key) to release the lock; otherwise the server will release it after the timeout.

TryLock (string, int) Method

trylock is non‑blocking: it returns immediately with a key if the lock is acquired, or empty data if the lock is already held.

Go Example

import "github.com/donnie4w/tlmq-go/cli"

sc := cli.NewMqClient("ws://127.0.0.1:5001", "mymq=123")
sc.Connect()
key, err := sc.Lock("testlock", 3)
if err != nil {
    // handle error
} else {
    defer sc.UnLock(key)
    // business logic
}

// tryLock example (non‑blocking)
if key, ok := sc.TryLock("testlock2", 3); ok {
    defer sc.UnLock(key)
    // business logic
}

// spin‑wait tryLock
var key string
for {
    if v, ok := sc.TryLock("testlock", 3); ok {
        key = v
        break
    } else {
        <-time.After(100 * time.Millisecond)
    }
}
defer sc.UnLock(key)
// business logic

Java Example

<dependency>
    <groupId>io.github.donnie4w</groupId>
    <artifactId>tlmq-j</artifactId>
    <version>0.0.2</version>
</dependency>

MqClient mc = new SimpleClient("ws://127.0.0.1:5001", "mymq=123");
mc.connect();
String key = null;
try {
    key = mc.lock("testlock", 3);
    // business logic
} finally {
    if (key != null) {
        mc.unLock(key);
    }
}

// tryLock example
String key = null;
try {
    key = mc.tryLock("testlock", 3);
    // business logic
} finally {
    if (key != null) {
        mc.unLock(key);
    }
}

Test results show multi‑threaded concurrency using both lock and tryLock with spin‑wait, illustrated by the included performance charts.

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