= Debugging Camel K Integrations

Sometimes integrations can fail or behave unexpectedly for unknown reasons and a developer needs to investigate the cause of such behavior.
Attaching a Java debugger to an integration is a common way to start the investigation.

Even if Camel K integrations run on a Kubernetes cluster, it's very easy to attach a Java debugger to the remote integration using the CLI.

If you're a VS Code user, you can watch this link:https://www.youtube.com/watch?v=cFPuxd1Je3c[video].

Find below a more generic explanation using IntelliJ.

Suppose you just launched an integration using the following command:

[source,shell]
----
kamel run examples/Sample.java
----

An integration named `sample` should be running in the cluster.
You can use the `kamel debug` command to put it in "debug mode".

[source,shell]
----
kamel debug sample
----

A possible output that you may find is the following:

[source,shell]
----
$ kamel debug sample
Enabling debug mode on integration "sample"...
[1] Monitoring pod sample-8455c8b985-5cxvc
[1] exec java -agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=*:5005 -cp ./resources:[..omitted..] io.quarkus.runner.GeneratedMain
[1] Listening for transport dt_socket at address: 5005
Forwarding from 127.0.0.1:5005 -> 5005
Forwarding from [::1]:5005 -> 5005
----

As you can see in the logs, the CLI has configured the integration in debug mode (see option `-agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=*:5005`)
and started forwarding the local port 5005 on the workstation machine (local port can be changed using the `--port` option) to the container port 5005, where the JVM is waiting for a debugger.

The JVM is suspended and waits for a debugger to attach by default: this behavior can be turned off using the `--suspend=false` option.

Last thing to do is, with your IDE opened on the **integration file (if using Java, Groovy or Kotlin), the Apache Camel project or the Camel K Runtime project**,
to start a remote debugger on `localhost:5005`.

The following picture shows the configuration of a remote debugger in IntelliJ Idea.

image::debugging/remote-debugger.png[Configuration of the remote debugger in IntelliJ Idea]

Once you configure a debugger, you can **add breakpoints** to various part of the code, then connect the debugger to trigger the JVM startup.

When the debugging session is finished, hitting *ctrl+c* on the terminal where the kamel CLI is running will restore the integration to its original status.
