Got a unique requirement yesterday where one process on Red Hat Fuse consuming a very long time, therefore creating lots of timeout error from frontend. It happen because some process on Fuse performing a very complicated task and we cannot modified existing api flow due to business requirements.

For this example, i want to simulate the same slowness on my Fuse + Spring Boot app,

package com.redhat.edw;

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

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

A simple camel route,

package com.redhat.edw;

import org.apache.camel.builder.RouteBuilder;
import org.apache.camel.model.rest.RestBindingMode;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component
public class Routes extends RouteBuilder {
    @Override
    public void configure() throws Exception {
        restConfiguration("servlet")
                .bindingMode(RestBindingMode.json)
        ;

        rest()
                .get("hello")
                .route()
                .setBody(method("helloRouteHandler", "setHelloWithName"))
                .endRest()
        ;
    }
}

A placeholder bean,

package com.redhat.edw;

import lombok.*;

@Data
@ToString
@AllArgsConstructor
@NoArgsConstructor
@Builder
public class HelloResponse {
    private String content;
}

And a Handler class,

package com.redhat.edw;

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Slf4j
@Component("helloRouteHandler")
public class HelloRouteHandler {

    @Value("${name}")
    private String name;

    public HelloResponse setHelloWithName() throws Exception {

        /*
         * simulate a very long process (10second)
         */
        Thread.sleep(10000);

        /*
         * this process will still getting called after 10 second regardless of sync or async
         */
        log.info("calling hello for "+name);

        return HelloResponse.builder().content(name).build();
    }
}

And two simple properties file,

# The Camel context name
camel.springboot.name=FuseHelloWorld

# enable all management endpoints
endpoints.enabled=true
management.security.enabled=false

camel.component.servlet.mapping.contextPath=/api/*

name=Edwin

# OpenShift ConfigMap name
spring.application.name=fuse-hello-world

spring.cloud.kubernetes.reload.enabled=true
spring.cloud.kubernetes.reload.strategy=restart_context
spring.cloud.kubernetes.reload.monitoring-config-maps=true
spring.cloud.kubernetes.reload.monitoring-secrets=true
spring.cloud.kubernetes.reload.mode=polling

Run the project and try calling /api/hello api and see how much time is needed to give response time.

As you can see, 10seconds is not an acceptable response for a regular web user and wee need to improve it. The workaround is quite simple, Spring have an @Async method which we will utilize on Handler class,

package com.redhat.edw;

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Component;

@Slf4j
@Component("helloRouteHandler")
public class HelloRouteHandler {

    @Value("${name}")
    private String name;

    @Async
    public HelloResponse setHelloWithName() throws Exception {

        /*
         * simulate a very long process (10second)
         */
        Thread.sleep(10000);

        /*
         * this process will still getting called after 10 second regardless of sync or async
         */
        log.info("calling hello for "+name);

        return HelloResponse.builder().content(name).build();
    }
}

Which will give a faster response,

And we can deploy our code to Openshift by using this command,

mvn fabric8:deploy -Pfabric8

A successful deployment will looks like this,

And finally, the complete code can be downloaded from this url,

https://github.com/edwin/fuse-with-async-http