feat: added spring cloud function sample

samples/spring-cloud-function-demo/README.MD

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+# Spring Cloud Function AWS Demo
+
+This project demonstrates how to use Spring Cloud Function with AWS Lambda, showcasing function routing, and deployment to AWS Lambda using AWS SAM.
+
+## Overview
+
+Spring Cloud Function is a framework that promotes the implementation of business logic via functions. It abstracts away the underlying runtime platform, allowing the same code to run as a web endpoint, a stream processor, or a task. This project demonstrates:
+
+- Function definition and routing
+- Custom message routing
+- Deployment to AWS Lambda
+- Integration with AWS services (API Gateway, SQS)
+
+## Project Structure
+
+- `SpringCloudFunctionDemo.java`: Main application class with function definitions
+- `Unicorn.java`: Simple data model class
+- `template.yaml`: AWS SAM template for deployment
+- `TestHttp.http`: HTTP request examples for local testing
+
+## Functions Implemented
+
+This demo includes several function implementations:
+
+- `lowerCase`: Converts input string to lowercase
+- `upperCase`: Converts input string to uppercase
+- `reverse`: Reverses the input string
+- `helloUnicorn`: Processes a Unicorn object and returns a greeting
+- `asyncProcessor`: Consumes SQS events and logs the number of messages processed
+- `noOpFunction`: Default function when no proper routing is found
+
+## Custom Routing
+
+The application demonstrates custom routing using `MessageRoutingCallback`. The router inspects the `x-routing-key` header and routes to the appropriate function:
+
+- `uppercase` → `upperCase` function
+- `lowercase` → `lowerCase` function
+- `reverse` → `reverse` function
+- `unicorn` → `helloUnicorn` function
+
+## Local Development
+
+### Prerequisites
+
+- Java 21
+- Maven
+- AWS SAM CLI (for deployment)
+
+### Building the Application
+
+```bash
+mvn clean package
+```
+
+### Running Locally
+
+```bash
+mvn spring-boot:run
+```
+
+Once running, you can test the functions using the provided `TestHttp.http` file or with curl:
+
+```bash
+# Test lowercase function
+curl -X POST http://localhost:8080/lowerCase -H "Content-Type: text/plain" -d "HELLO WORLD"
+
+# Test uppercase function
+curl -X POST http://localhost:8080/upperCase -H "Content-Type: text/plain" -d "hello world"
+
+# Test custom routing
+curl -X POST http://localhost:8080/functionRouter -H "Content-Type: text/plain" -H "x-routing-key: uppercase" -d "hello world"
+```
+
+## AWS Deployment
+
+This project uses AWS SAM for deployment to AWS Lambda.
+
+### Prerequisites
+
+- AWS CLI configured with appropriate credentials
+- AWS SAM CLI installed
+
+### Deployment Steps
+
+1. Build the application:
+   ```bash
+   mvn clean package
+   ```
+
+2. Deploy using SAM:
+   ```bash
+   sam deploy --guided
+   ```
+
+3. Follow the prompts to complete the deployment.
+
+### AWS Resources Created
+
+The SAM template creates the following resources:
+
+- **API Gateway**: Exposes the Spring Cloud Function as a REST API
+- **Lambda Functions**:
+  - `SpringCloudFunction`: Handles API requests
+  - `MessageProcessor`: Processes SQS messages
+- **SQS Queue**: For asynchronous message processing
+
+## Testing in AWS
+
+After deployment, you can test the API using the endpoint URL provided in the outputs:
+
+```bash
+# Test the deployed API
+curl -X POST https://{api-id}.execute-api.{region}.amazonaws.com/Prod/uppercase/ -H "Content-Type: text/plain" -d "hello world"
+```
+
+To test the SQS integration, send a message to the created queue:
+
+```bash
+aws sqs send-message --queue-url {QueueURL} --message-body "Test message"
+```
+
+## Function Composition
+
+Spring Cloud Function supports function composition. For example:
+
+```bash
+# Apply reverse then uppercase
+curl -X POST http://localhost:8080/reverse,upperCase -H "Content-Type: text/plain" -d "hello world"
+```
+
+This will first reverse "hello world" to "dlrow olleh" and then convert it to uppercase: "DLROW OLLEH".
+
+## Additional Resources
+
+- [Spring Cloud Function Documentation](https://spring.io/projects/spring-cloud-function)
+- [AWS Lambda Java Runtime](https://docs.aws.amazon.com/lambda/latest/dg/lambda-java.html)
+- [AWS Serverless Application Model (SAM)](https://aws.amazon.com/serverless/sam/)
+
+## License
+
+This project is licensed under the MIT License - see the LICENSE file for details.

samples/spring-cloud-function-demo/TestHttp.http

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+### Test lowerCase function
+POST http://localhost:8080/lowerCase
+Content-Type: text/plain
+
+HELLO SPRING I/O
+
+### Test upperCase function
+POST http://localhost:8080/upperCase
+Content-Type: text/plain
+
+hello spring i/o
+
+### Test reverse function
+POST http://localhost:8080/reverse
+Content-Type: text/plain
+
+hello world
+
+### Test helloUnicorn function
+POST http://localhost:8080/helloUnicorn
+Content-Type: application/json
+
+{
+  "name": "Sparkles",
+  "age": 5
+}
+
+### Test function composition (upperCase after reverse)
+POST http://localhost:8080/reverse,upperCase
+Content-Type: text/plain
+
+hello world
+
+
+### Test routing to lowerCase function using custom router
+POST http://localhost:8080/functionRouter
+Content-Type: application/json
+x-routing-key: lowercase
+
+HELLO WORLD
+
+### Test routing to upperCase function using custom router
+POST http://localhost:8080/functionRouter
+Content-Type: application/json
+x-routing-key: uppercase
+
+hello world
+
+
+### Test routing to upperCase function using custom router
+POST http://localhost:8080/functionRouter
+Content-Type: application/json
+
+hello world

samples/spring-cloud-function-demo/pom.xml

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+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-starter-parent</artifactId>
+        <version>3.4.5</version>
+    </parent>
+    <groupId>com.amazonaws.demo</groupId>
+    <artifactId>spring-cloud-function-demo</artifactId>
+    <version>1.0</version>
+    <packaging>jar</packaging>
+    <name>Example application to route to different Spring Cloud Functions</name>
+    <properties>
+        <maven.compiler.target>21</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
+        <spring-cloud-function.version>4.2.2</spring-cloud-function.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.cloud</groupId>
+            <artifactId>spring-cloud-function-context</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.cloud</groupId>
+            <artifactId>spring-cloud-function-adapter-aws</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.cloud</groupId>
+            <artifactId>spring-cloud-starter-function-web</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>com.amazonaws</groupId>
+            <artifactId>aws-lambda-java-events</artifactId>
+            <version>3.15.0</version>
+        </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-api</artifactId>
+            <version>2.0.17</version>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>5.10.2</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>org.springframework.cloud</groupId>
+                <artifactId>spring-cloud-function-dependencies</artifactId>
+                <version>${spring-cloud-function.version}</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+
+        </dependencies>
+    </dependencyManagement>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-deploy-plugin</artifactId>
+                <configuration>
+                    <skip>true</skip>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+                <dependencies>
+                    <dependency>
+                        <groupId>org.springframework.boot.experimental</groupId>
+                        <artifactId>spring-boot-thin-layout</artifactId>
+                        <version>1.0.31.RELEASE</version>
+                    </dependency>
+                </dependencies>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-shade-plugin</artifactId>
+                <version>3.6.0</version>
+                <configuration>
+                    <createDependencyReducedPom>false</createDependencyReducedPom>
+                    <shadedArtifactAttached>true</shadedArtifactAttached>
+                    <shadedClassifierName>aws</shadedClassifierName>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+</project>

samples/spring-cloud-function-demo/src/main/java/com/amazonaws/demo/SpringCloudFunctionDemo.java

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+package com.amazonaws.demo;
+
+import com.amazonaws.services.lambda.runtime.events.SQSEvent;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.cloud.function.context.MessageRoutingCallback;
+import org.springframework.cloud.function.context.config.RoutingFunction;
+import org.springframework.context.annotation.Bean;
+import org.springframework.messaging.Message;
+
+import java.util.function.Consumer;
+import java.util.function.Function;
+
+@SpringBootApplication
+public class SpringCloudFunctionDemo {
+
+    public static void main(String[] args) {
+        SpringApplication.run(SpringCloudFunctionDemo.class, args);
+    }
+
+    @Bean
+    public Function<String, String> lowerCase() {return String::toLowerCase;}
+
+    @Bean
+    public Function<String, String> upperCase(){
+        return String::toUpperCase;
+    }
+
+    @Bean
+    public Function<String, String> reverse(){
+        return value -> new StringBuilder(value).reverse().toString();
+    }
+
+    @Bean
+    public Function<com.amazonaws.demo.Unicorn, String> helloUnicorn(){
+        return value -> "Hello %s! You are %d years old!".formatted(value.name(), value.age());
+    }
+
+    @Bean
+    public Consumer<SQSEvent> asyncProcessor(){
+        return value -> System.out.printf("Processed %d messages!", value.getRecords().size());
+    }
+
+    @Bean
+    public Function<String, String> noOpFunction(){
+        return value -> "No proper function found!";
+    }
+
+    @Bean
+    public MessageRoutingCallback customRouter() {
+        return new MessageRoutingCallback() {
+            @Override
+            public String routingResult(Message<?> message) {
+                System.out.println("Hello from MessageRoutingCallback");
+                var routingKey = message.getHeaders().getOrDefault("x-routing-key", "").toString();
+                return switch (routingKey) {
+                    case "uppercase" -> "upperCase";
+                    case "lowercase" -> "lowerCase";
+                    case "reverse" -> "reverse";
+                    case "unicorn" -> "helloUnicorn";
+                    default -> "noOpFunction";
+                };
+            }
+        };
+    }
+}

samples/spring-cloud-function-demo/src/main/java/com/amazonaws/demo/Unicorn.java

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+package com.amazonaws.demo;
+
+public record Unicorn(String name, int age) { }
+

samples/spring-cloud-function-demo/src/main/resources/application.properties

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+# Function configuration
+spring.cloud.function.routing.enabled=true