khs-trouble-maker-client

Servlet that is registered with clients of the Trouble Maker framework used to randomly produce server trouble issues.

##Quick Links Trouble Maker

Trouble Maker Spring Boot Starter

Trouble Maker Website

Installation

Add this dependency to your POM.XML:

<dependency>
	<groupId>com.keyholesoftware</groupId>
	<artifactId>khs-trouble-maker-client</artifactId>
	<version>1.0.1</version>
</dependency>	

Register this Java Servlet in your web.xml or config:

<servlet>
	 <servlet-name>trouble</servlet-name>
	  <servlet-class>khs.trouble.servlet</servlet-class>
	     <init-param>
            <param-name>token</param-name>
            <!-- token should match dashboard token -->
            <param-value>abc123</param-value>
        </init-param>
	</servlet>
	<servlet-mapping>
	    <servlet-name>trouble</servlet-name>
	    <url-pattern>/trouble/*</url-pattern>
</servlet-mapping>

Actions

By default, Trouble Maker actions will be performed by calling the following URIs, if a matching access token is defined in the request header. The Trouble Maker dashboard will invoke these URIs.

http://<server>/trouble/kill - Kills the service with a System.exit() command.

http://<server>/trouble/memory - Executes a thread that fills up heap memory and keeps it there for the timeout period.

http://<server>/trouble/load - Spawns specified number of threads the block for the the timeout period.

http://<server>/trouble/exception - Throws an exception to validate exception handling behavior of a service.

Defining Custom Actions Code Blocks

If you want to apply your own trouble actions and override the supplied defaults, yYou can create a class that extends from this supplied abstract class, as shown below.

public class MyKillCodeBlock extends BaseCodeBlokc{	
	public KillBlock(long timeout) {
	super(timeout);
 }
	@Override
	public void eval() {
		// Do stuff to kill this process...like..
		System.exit(-1)
	}	
}

Then you will need to register the action as a parameter for the trouble servlet when defining it in the web.xml. The example below shows how a custom load action is registered:

...
<servlet>
	 <servlet-name>trouble</servlet-name>
	  <servlet-class>khs.trouble.servlet</servlet-class>
		...
        <init-param>
           <!-- Overriding the Kill Action Block -->
            <param-name>kill</param-name>
            <param-value>com.mytrouble.MyKill</param-value>
        </init-param>
 
</servlet>
...

Here's the kill operation names you can use to override, through servlet init parameters:

• kill
• load
• memory
• exception