Error running Spring Boot Azure Function App

Question

I was trying to run this example. I made some changes in the function handlers, pom.xml and project structure but I don't think they would change the way the app runs.

Anyway, my problem occurs when I run ./mvnw azure-functions:run, for some reason it's not finding my handler.

Functions:

        Hello: [GET] http://localhost:7071/api/hello

For detailed output, run func with --verbose flag.
[2021-06-17T17:10:26.980Z] Received FunctionLoadResponse for functionId:1a1ed97a-ac24-43f8-870a-b39887543787
[2021-06-17T17:10:26.982Z] Worker failed to function id 1a1ed97a-ac24-43f8-870a-b39887543787.
[2021-06-17T17:10:26.982Z] Result: Failure
[2021-06-17T17:10:26.982Z] Exception: ClassNotFoundException: com.example.app.modules.HelloHandler
[2021-06-17T17:10:26.982Z] Stack: java.lang.ClassNotFoundException: com.example.app.modules.HelloHandler
[2021-06-17T17:10:26.982Z]      at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:471)
[2021-06-17T17:10:26.982Z]      at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:589)
[2021-06-17T17:10:26.982Z]      at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
[2021-06-17T17:10:26.982Z]      at java.base/java.lang.Class.forName0(Native Method)
[2021-06-17T17:10:26.982Z]      at java.base/java.lang.Class.forName(Class.java:398)
[2021-06-17T17:10:26.982Z]      at com.microsoft.azure.functions.worker.broker.EnhancedJavaMethodExecutorImpl.getContainingClass(EnhancedJavaMethodExecutorImpl.java:63)
[2021-06-17T17:10:26.982Z]      at com.microsoft.azure.functions.worker.broker.EnhancedJavaMethodExecutorImpl.<init>(EnhancedJavaMethodExecutorImpl.java:22)
[2021-06-17T17:10:26.982Z]      at com.microsoft.azure.functions.worker.broker.FactoryJavaMethodExecutor.getJavaMethodExecutor(FactoryJavaMethodExecutor.java:20)
[2021-06-17T17:10:26.982Z]      at com.microsoft.azure.functions.worker.broker.JavaFunctionBroker.loadMethod(JavaFunctionBroker.java:38)
[2021-06-17T17:10:26.982Z]      at com.microsoft.azure.functions.worker.handler.FunctionLoadRequestHandler.execute(FunctionLoadRequestHandler.java:27)
[2021-06-17T17:10:26.982Z]      at com.microsoft.azure.functions.worker.handler.FunctionLoadRequestHandler.execute(FunctionLoadRequestHandler.java:9)
[2021-06-17T17:10:26.982Z]      at com.microsoft.azure.functions.worker.handler.MessageHandler.handle(MessageHandler.java:45)
[2021-06-17T17:10:26.983Z]      at com.microsoft.azure.functions.worker.JavaWorkerClient$StreamingMessagePeer.lambda$onNext$0(JavaWorkerClient.java:92)
[2021-06-17T17:10:26.983Z]      at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
[2021-06-17T17:10:26.983Z]      at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
[2021-06-17T17:10:26.983Z]      at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
[2021-06-17T17:10:26.983Z]      at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
[2021-06-17T17:10:26.983Z]      at java.base/java.lang.Thread.run(Thread.java:829)
[2021-06-17T17:10:26.983Z] .
[2021-06-17T17:10:31.849Z] Host lock lease acquired by instance ID '00000000000000000000000001758684'.

But when I run ./mvnw spring-boot:run, only the Hello.apply() method works. Is this an Azure Dependencies issue?

Here is my code/structure:

Project's structure

src/main
├── azure
│   ├── host.json
│   └── local.settings.json
├── java
│   └── com
│       └── example
│           └── app
│               ├── ExampleApplication.java
│               └── modules
│                   ├── HelloHandler.java
│                   └── Hello.java
└── resources
    └── config
        └── application.yml

pom.xml (only the changes I made)

...
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-function-adapter-azure</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-function-webflux</artifactId>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>com.microsoft.sqlserver</groupId>
            <artifactId>mssql-jdbc</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    ...
    </dependencies>
    ...
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>
                <groupId>com.microsoft.azure</groupId>
                <artifactId>azure-functions-maven-plugin</artifactId>
                <version>1.12.0</version>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-resources-plugin</artifactId>
                <version>3.2.0</version>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-dependency-plugin</artifactId>
                <version>3.1.2</version>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-clean-plugin</artifactId>
                <version>3.1.0</version>
            </plugin>
        </plugins>
    ...
    </build>

ExampleApplication.java

package com.example.app;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class ExampleApplication {

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

}

HelloHandler.java

package com.example.app.modules;

import com.microsoft.azure.functions.*;
import com.microsoft.azure.functions.annotation.AuthorizationLevel;
import com.microsoft.azure.functions.annotation.FunctionName;
import com.microsoft.azure.functions.annotation.HttpTrigger;
import org.springframework.cloud.function.adapter.azure.FunctionInvoker;

import java.util.Optional;

public class HelloHandler extends FunctionInvoker<String, String> {

    @FunctionName("Hello")
    public HttpResponseMessage execute(
            @HttpTrigger(
                name = "request",
                methods = {HttpMethod.GET},
                authLevel = AuthorizationLevel.ANONYMOUS,
                route = "hello"
            ) HttpRequestMessage<Optional<String>> request, ExecutionContext context
    ) {
        String message = request.getQueryParameters().get("message");
        return request
                .createResponseBuilder(HttpStatus.OK)
                .body(handleRequest(message, context))
                .header("Content-Type", "application/json")
                .build();
    }
}

Hello.java

package com.example.app.modules;

import org.springframework.stereotype.Component;
import reactor.core.publisher.Mono;

import java.util.function.Function;

@Component
public class Hello implements Function<Mono<String>, Mono<String>> {
    @Override
    public Mono<String> apply(Mono<String> mono) {
        return mono.map(string -> "Your message was: " + string);
    }
}

Answer 1

Great to hear that you got it working. According to your comment, did you put spring-boot-maven-plugin at the end of the pom.xml as follows?

    <build>
        <plugins>

            <plugin>
                <groupId>com.microsoft.azure</groupId>
                <artifactId>azure-functions-maven-plugin</artifactId>
                <version>1.12.0</version>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-resources-plugin</artifactId>
                <version>3.2.0</version>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-dependency-plugin</artifactId>
                <version>3.1.2</version>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-clean-plugin</artifactId>
                <version>3.1.0</version>
            </plugin>
            
           <!-- OP put spring-boot-maven-plugin at the end -->
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    ...
    </build>