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Sunday, March 3, 2024

Spring Boot Beginners: Introducing Spring Functions Catalog

 Spring Boot Beginners: Introducing Spring Functions Catalog

Hey there, Spring Boot enthusiasts! Are you looking for ready-made, reusable functions to add superpowers to your applications? Look no further than the Spring Functions Catalog, a new project from the Spring Cloud Dataflow team.

What is Spring Functions Catalog?

Think of it as a toolbox filled with pre-built Java functions, each specializing in a specific task. These functions are like tiny building blocks that you can easily add to your Spring Boot applications and use "as-is" to perform various actions.

Benefits of using Spring Functions Catalog:

  • Save time and effort: No need to write code from scratch for common tasks like reading files, sending messages, or data manipulation.
  • Simplify complex workflows: Combine different functions together to create powerful and customized application logic.
  • Easy integration: Simply add the library to your project and start using the functions!

Examples of included functions:

  • sftpSupplier: Retrieves files from a remote SFTP server.
  • kafkaPublisher: Sends messages to a Kafka topic.
  • aggregatorFunction: Groups multiple inputs into one based on a specific key.

How to use Spring Functions Catalog:

  1. Add the dependency: Include the Spring Functions Catalog library in your project's build configuration (e.g., Gradle or Maven).
  2. Choose and use functions: Pick the functions you need and inject them into your application code. You can also compose different functions to create more complex workflows.

Ready to try it out?

The Spring Functions Catalog is still under development (currently in M1 release), but you can experiment with it and provide feedback. The goal is to reach a stable release (GA) in April 2024.

Here's an example of using Spring Functions Catalog with Spring Boot:

1. Add the dependency:

In your pom.xml file (if using Maven) or build.gradle file (if using Gradle), add the following dependency:

XML
<dependency>
    <groupId>org.springframework.cloud.fn</groupId>
    <artifactId>spring-time-supplier</artifactId>
    <version>5.0.0-M1</version>
</dependency>

<dependency>
    <groupId>org.springframework.cloud.fn</groupId>
    <artifactId>spring-log-consumer</artifactId>
    <version>5.0.0-M1</version>
</dependency>

This code snippet adds two dependencies:

  • spring-time-supplier: Provides a function that returns the current timestamp.
  • spring-log-consumer: Provides a function that logs a message to the console.

2. Create a Spring Boot application:

Here's a simple Spring Boot application that uses the functions:

Java
@SpringBootApplication
public class TimeLogApplication {

    @Bean
    public Function<Void, String> composedFunction(TimeSupplier timeSupplier, LogConsumer logConsumer) {
        return timeSupplier.andThen(time -> "Current time: " + time);
    }

    @Scheduled(fixedDelay = 1000)
    public void scheduleFunctionCall(Function<Void, String> composedFunction) {
        composedFunction.apply(null);
    }

    public static void main(String[] args) {
        SpringApplication.run(TimeLogApplication.class, args);
    }
}

Explanation:

  • We define a composedFunction bean that combines the timeSupplier and logConsumer functions using the andThen method. This creates a new function that retrieves the current time and then logs it to the console.
  • The @Scheduled annotation schedules the scheduleFunctionCall method to be called every second.
  • This method simply calls the composedFunction, which retrieves the current time and logs it.

3. Run the application:

Run your Spring Boot application using your preferred method (e.g., mvn spring-boot:run or gradle bootRun). You should see the current time being logged to the console every second.

This is a simple example, but it demonstrates how you can use Spring Functions Catalog to easily add functionality to your Spring Boot applications. You can explore the different functions available in the catalog and combine them to create more complex workflows.

For more information:

  • Check out the Spring Functions Catalog GitHub repository: https://github.com/spring-cloud/spring-functions-catalog.
  • Explore the sample applications in the repository to see how the functions are used in practice.

Get started with Spring Functions Catalog today and unlock a new level of functionality in your Spring Boot applications!