📆 @nodeboot/starter-scheduler – Node-Boot Scheduling Starter

Overview

The @nodeboot/starter-scheduler package provides a simple yet powerful mechanism to schedule jobs within a Node-Boot application, similar to how Spring Boot Scheduler works.

It leverages node-cron under the hood to execute scheduled tasks at specified intervals based on cron expressions.

With minimal configuration, developers can automatically trigger functions within beans using the @Scheduler decorator.

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✨ Features

✅ Annotation-based scheduling – Just add @Scheduler(cronExpression) to any bean method.
✅ Cron-based execution – Supports flexible scheduling using cron expressions.
✅ Lifecycle-aware – Scheduling starts when the application initializes.
✅ Minimal setup – Requires only @EnableScheduling to activate.

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🚀 Installation

Ensure you have Node-Boot installed in your project. Then, install the scheduler starter package:

``sh
pnpm add @nodeboot/starter-scheduler
`

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🔥 Usage

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To activate the scheduling system, add @EnableScheduling() to your application class:

`typescript
import {EnableScheduling} from "@nodeboot/starter-scheduler";
import {NodeBootApplication, NodeBoot, ExpressServer} from "@nodeboot/core";

@EnableScheduling()
@NodeBootApplication()
export class SampleApp implements NodeBootApp {
start(): Promise {
return NodeBoot.run(ExpressServer);
}
}
`

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To schedule a method to run at a specific interval, add the @Scheduler decorator to a method inside a bean (@Service, @Component, etc.).

The method will automatically run based on the cron expression provided.

#### Example: Run a Task Every Minute

`typescript
import {Scheduler} from "@nodeboot/starter-scheduler";
import {Service} from "@nodeboot/core";

@Service()
export class TaskService {
@Scheduler(" *") // Runs every minute
public logMessage() {
console.log(Task executed at: ${new Date().toISOString()});
}
}
`

✅ This will log a message every minute! 🕒

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The @Scheduler decorator follows standard cron syntax:

`plaintext
*
│ │ │ │ │
│ │ │ │ └── Day of the Week (0-6, Sunday = 0)
│ │ │ └──── Month (1-12)
│ │ └─────── Day of the Month (1-31)
│ └────────── Hour (0-23)
└──────────── Minute (0-59)
`

| Expression | Meaning |
| --------------- | --------------------------------- |
| " *" | Runs every minute |
| "0 " | Runs every hour (at 0 min) |
| "0 0 *" | Runs daily at midnight |
| "0 0 1" | Runs every Monday at midnight |
| "/5 *" | Runs every 5 minutes |

For more advanced cron expressions, refer to node-cron documentation.

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🛠️ How It Works Internally

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This decorator:

- Registers the method as a scheduled job.
- Uses the Adapter Pattern to integrate with the Node-Boot lifecycle.
- Triggers execution based on the cron expression.

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- Enables automatic scheduling in the application.
- Registers the Scheduler Adapter into the Node-Boot lifecycle.
- Ensures all @Scheduler jobs are scheduled at startup.

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🎯 Example: Sending Notifications Every Hour

Imagine you need to send notifications to users every hour. You can achieve this with:

`typescript
import {Scheduler} from "@nodeboot/starter-scheduler";
import {Service} from "@nodeboot/core";

@Service()
export class NotificationService {
@Scheduler("0 ") // Runs at the start of every hour
public sendNotifications() {
console.log(📢 Sending notifications to users at ${new Date().toISOString()});
}
}
`

🔔 This will trigger notifications every hour, automatically!

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⚠️ Common Issues & Debugging

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✔️ Ensure @EnableScheduling() is added to your application class.
✔️ Verify the cron expression is correct.
✔️ Check the logs to see if the scheduler is registered.

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📚 Additional Resources

- Node-Cron Documentation
- Understanding Cron Expressions
- Node-Boot Framework

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🎉 Conclusion

The @nodeboot/starter-scheduler package makes scheduling effortless and declarative within Node-Boot applications.

By simply adding @Scheduler(cronExpression)`, you can automate periodic tasks, without manually managing timers.

Happy scheduling! 🚀🎯