EMACS Debug Adapter client for Apache Camel

How to debug Camel with emacs

I just got the debug integration for camel in emacs running using (https://emacs-lsp.github.io/dap-mode/page/adding-debug-server/). In order to not forget the config, I decided to quickly compile this readme.

Prerequisites

• Camel version 3.18+
• camel-debug is available on the classpath
• have JMX enabled

How to configure Emacs

In a ~/.emacs.d/dap-camel.el file:

(dap-register-debug-provider
 "camel"
 (lambda (conf)
   (plist-put conf :host "localhost")
   conf))

(dap-register-debug-template "Camel Attach"
                             (list :type "camel"
                                   :request "attach"
                                   :port 1099
                                   :dap-server-path '("java" "-jar" "PATH/TO/camel-dap-server-0.4.0.jar")
                                   :name "Run Configuration"))

M-x eval-buffer

How to get Camel Debug Adapter server.jar file?

• To get a jar file either you can compile the source or download from the Maven Central repository.
• To download from Maven Central repository

cd /home
curl -LO https://repo1.maven.org/maven2/com/github/camel-tooling/camel-dap-server/0.4.0/camel-dap-server-0.4.0.jar

How to attach camel application to emacs for debugging

• To test the camel application debugging need a working example. Lot of good examples are provided in this repo, camel-examples.

• To enable Camel Textual Route debugging, you need to launch this examples with mvn camel:debug.

• I have specifically used example-main in this setup.

In Terminal

  cd ~/camel-examples/examples/main

• vim src/main/java/org/apache/camel/example/MyBean.java
• Add the following content inside MyBean.java file:

package org.apache.camel.example;

public class MyBean {

    private String hi;

    public MyBean(String hi) {
        this.hi = hi;
    }

    public String hello() {
        return hi + " Begin ? ";

    }
     public String bye() {
        return hi + " End ? ";
}
}

• Compile the source to reflect the new changes

mvn compile

• Launch this example with the profile camel.debug

 mvn camel:run -Pcamel.debug

Make the following changes and run your camel application

• M-x load-file
• Load file: ~/camel-examples/examples/main/src/main/java/org/apache/camel/example/MyRouteBuilder. java
• Inside MyRouteBuilder.java file:

package org.apache.camel.example;

import org.apache.camel.builder.RouteBuilder;

public class MyRouteBuilder extends RouteBuilder {

    @Override
    public void configure() throws Exception {
        from("timer:foo").routeId("foo")
            .bean("myBean", "hello")
            .log("${body}")
            .bean("myBean", "bye")
            .log("${body}");
    }
}

Debug It

To set the breakpoints

M-x dap-breakpoint-add

Now everything is in place. Open the main MyRouteBuilder file and start debugging by:

M-x dap-debug

Select configuration template: Camel Attach

Enjoy the Debug Adapter for Apache Camel in Emacs.