tldb Distributed Lock: Usage Guide for Go and Java

Distributed locks are essential tools in distributed systems. tldb offers a simple, reliable distributed lock service that mimics object‑level locking in a program, simplifying design by using a string as the lock identifier.

Lock, TryLock, and Unlock Methods

tldb provides three main operations:

lock : a blocking call that waits until the lock is granted.

tryLock : a non‑blocking call that returns immediately with a lock key if successful, or empty if the lock is already held.

unlock : releases a previously acquired lock using the returned key.

Go Client Example

First, import the Go client library:

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

Lock (blocking) example:

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 (non‑blocking) example:

sc := cli.NewMqClient("ws://127.0.0.1:5001", "mymq=123")
sc.Connect()
if key, ok := sc.TryLock("testlock2", 3); ok {
    defer sc.UnLock(key)
    // business logic
}

Spin‑wait using 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 Client Example

Add the Maven dependency:

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

Lock (blocking) example:

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 (non‑blocking) example:

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

These examples demonstrate how to acquire and release tldb distributed locks from both Go and Java clients, enabling cross‑language lock coordination in a message‑queue based architecture.