JavaMonitor is a web-based tool used to configure and maintain deployed WebObjects applications. It is capable of handling multiple WebObjects applications, multiple instances of each application, and multiple WebObjects Applications Servers. In most cases you'll have one instance of JavaMonitor controlling all instances of your applications, even if they are spread across multiple Application Servers.
wotaskd (WebObjects task daemon) is the WebObjects Deployment tool that manages the instances on an Application Server. It's used by Monitor to propagate site configuration changes throughout the site's application hosts.
Apple released the original wotaskd and JavaMonitor to the community as open source in WebObjects 5.4. The source was then quickly modified and included in Project Wonder. Substantial improvements in both functionality and look-and-feel have been made over the years. These improved versions of wotaskd.woa and JavaMonitor.woa are available as standard Wonder applications.
Where To Get Them
You can either download them pre-built from Wonder's Hudson build server or build them from the source code.
To build them from the Wonder source code, simply run the following command from the Wonder directory at the root of the Wonder source.
What this command does:
- ant: calls Apache Ant. It is assumed that you have this already installed.
- frameworks: tells Ant to build the "frameworks" target. This may not be needed if you already have Wonder built and installed in a location Ant can find automatically.
- deployment.tools: tells Ant to build the "deployment.tools" target. This is the target that builds both wotaskd.woa and JavaMonitor.woa. You absolutely need this one.
- -Dwonder.patch=54: tells Wonder to build for WebObjects version 5.4. You need this if you are building against Wonder Trunk. Some branches don't need it, but it doesn't hurt either.
- -Ddeployment.standalone=true: argument will embed the required Wonder and WebObjects frameworks in built applications. You need this to ensure that the required frameworks are embedded in the built applications.
Major Improvements over Apple's versions
Automatic archive of SiteConfig.xml
On every change you make to an application's configuration, a backup of SiteConfig.xml will be created in, by default, /Library/WebObjects/Configuration.
In the "list instances" page, you get a "Bounce" action link. This action only work if you have at least one active instance and one inactive. What it does is :
- Find the inactive (i.e., not started) instance and start it
- Find the active instances (minus the one started in the previous step) and enable "Refuse New Session"
- Bounce the active instances when the minimum session count is reached
This feature, from Pascal's understanding, allows you to upload new versions of your application, start up the new version and refuse sessions for the instances running on the older version.
It is uncertain what will happen if the new version of your application makes changes to your database schema (e.g., uses ERXMigrations). The old instances may raise exceptions before they can gracefully shut down because the schema no longer matches what the old application's EOF expects. Try it out on a test server first and then update this page so everyone knows!
If you call
http://monitorhost:port/cgi-bin/WebObjects/JavaMonitor.woa/wa/statistics, JavaMonitor will send you back statistics, in JSON format, about instances, per application.
If JavaMonitor is configured with a password, and I hope you do, pass pw=monitorpassword as a argument to the query :
Direct Actions for Management Tasks
You can do most of the standard management tasks you'd normally do in JavaMonitor's web UI by calling standard WebObjects Direct Actions. Instead of using the
/wa/ request handler though, these management tasks use a new
/admin/ request handler. These Direct Actions can be very useful, especially if you need to restart instances or other do tasks from the command line, from within Ant or other build or deployment systems.
List of available direct actions :
?type=all: Returns details about all instances of all applications
AppName: Returns details about all instances of a specific application
?type=ins&name=AppName-InstanceNo: Returns details about one specific instance
stopped: return NO if the instance is running, YES if not.
bounce: more on it later.
clearDeaths: clear the number of deaths (same action as clicking the "Clear deaths" in JavaMonitor)
turnScheduledOn: turn scheduling on for an application or instance. Call /turnScheduledOff to do the opposite.
turnRefuseNewSessionsOn: turn "Refuse new sessions" on, call turnRefuseNewSessionsOff to do the opposite.
turnAutoRecoverOn: guess what? It activate "Auto recover"! And guess again? /turnAutoRecoverOff do the opposite!
forceQuit: force quit an application, might be useful to call it from a monitoring system.
stop: stop an application/instance the normal way.
start: start an application/instance the normal way.
?type=all : returns details about all applications and instances
?type=app&name=AppName : returns details about all instances of a specific application
?type=ins&name=AppName-InstanceNo : returns details about one specific instance
For example, if you want to get details about all instances and applications, you call :
To get details about the AjaxExample application :
And for a specific instance :
The response for the direct actions will either send a JSON array or YES/NO. For example, the query info for all instances will return :
List of available direct actions :
/info : return details (number of deaths, state, etc.; see above), in JSON, about an instance.
/running : return YES if the instance is running, NO if not.
/stopped : return NO if the instance is running, YES if not.
/bounce: more on it later.
/clearDeaths : clear the number of deaths (same action as clicking the "Clear deaths" in JavaMonitor)
/turnScheduledOn : turn scheduling on for an application or instance. Call /turnScheduledOff to do the opposite.
/turnRefuseNewSessionsOn : turn "Refuse new sessions" on, call turnRefuseNewSessionsOff to do the opposite.
/turnAutoRecoverOn : guess what? It activate "Auto recover"! And guess again? /turnAutoRecoverOff do the opposite!
/forceQuit : force quit an application, might be useful to call it from a monitoring system.
/stop : stop an application/instance the normal way.
/start : start an application/instance the normal way.
Remote Control via REST Routes
On September 28th 2010, REST routes were added in JavaMonitor. Those routes + the direct actions explained in this document allow you to control almost everything remotely (make sure that your JavaMonitor installation is secure!). As the direct actions, append ?pw=XXXX to the URLs if JavaMonitor is password protected.
Examples of REST calls :