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Debug Adapter for Apache Camel

Debug Adapter for Apache Camel based on the Debug Adapter Protocol and Eclipse LSP4J as SDK.

The Debug Adapter allows to set breakpoints and debug Camel textual DSLs.

Requirements

The Camel instance to debug must follow these requirements:

• Camel 3.16+
• Have camel-debug on the classpath
• Have JMX enabled

The Camel Debug Server Adapter must use Java Runtime Environment 11+ with com.sun.tools.attach.VirtualMachine (available in most JVMs such as Hotspot and OpenJDK).

Supported scope

• Attach only
• Camel DSLs:
  • Java DSL.
  • Yaml DSL. Note that the breakpoint must be set on the from/to line, not on the Camel URI line.
  • XML DSL in Camel Main mode. It implies that it is not working with Camel context specified in Camel XML file.
• Single context
• Add and remove breakpoint
• Inspect some variables when breakpoint is hit
• Stop on hit breakpoint
• Resume a single route instance and resume all
• Pause and resume route definitions (technically suspend/resume or stop/start Camel routes depending if they are suspendable or not)
• Stepping when the route definition is in the same file
• Update values of:
  • Common variables which are grouped in Debugger scope
  • Message body
  • Message header (for String types)
  • Exchange property (for String types)
• Conditional breakpoint with simple language. See here for details on how to write condition with simple language.
• Wait for all breakpoints to be ready to process messages when starting a new Camel application (requires Camel 3.18+). To activate it, use either camel:debug Maven goal, or org.apache.camel.debugger.suspend system property set to true or CAMEL_DEBUGGER_SUSPEND environment variable set to true.

Supported clients

All clients supporting the Debug Adapter protocol can be used. The configuration might be tricky for some of them. For easier configuration see:

• Specific client provided:
  • on Eclipse Desktop, install from this update site
  • on VS Code, for released version, see on Microsoft VS Code Marketplace, for snapshot binary see here
• Tutorial provided:
  • on vim

How to use it

• java -jar camel-dap-server-xxx.jar
• json parameter to provide on attach:

to use the default JMX url: service:jmx:rmi:///jndi/rmi://localhost:1099/jmxrmi/camel

{
"request": "attach"
}

or the JMX url can be explicitly specified:

{
"attach_jmx_url": "xxxxx",
"request": "attach"
}

or when running locally, the PID of the Camel application can be provided:

{
"attach_pid": "xxxxx",
"request": "attach"
}

Note that the request parameter is not part of the protocol but required by some clients (at least VS Code and Eclipse desktop).