OneAgent plugin for monitoring Java app executed by tomcat

[andrii_shevchyk]

Hello

I'm trying to create an OneAgent plugin which will monitor used system descriptors by Java app (executed by Tomcat).

Here is plugin.json for it:

{
  "name": "custom.python.descriptors_counter_plugin",
  "version": "0.01",
  "type": "python",
  "entity": "PROCESS_GROUP_INSTANCE",
  "metricGroup": "descriptors_counter_metrics",
  "processTypeNames": [
    "JAVA"
  ],
  "source": {
    "package": "descriptors_counter_plugin",
    "className": "DescriptorsPlugin",
    "activation": "Singleton"
  },
  "metrics": [
    {
      "timeseries": {
        "key": "used_descriptors",
        "unit": "Count",
        "displayname": "Used descriptors count"
      }
    }
  ],
  "configUI": {
    "displayName": "OneAgent Used Descriptors Plugin"
  }
}

And how it gets Process Group:

pgi = self.find_single_process_group(pgi_name('tomcat'))

On the server exists several tomcat groups.

I build it and uploaded it to Dynatrace but didn't find any changes for the tomcat section in UI.

Therefore several questions:

1. How to make sure that my plugin actually reached the hosts? I grep'ed through /opt/dynatrace/oneagent/log name of the plugin on one of them didn't find any mentions about my plugin;

2. What processTypeNames should I use in plugin.json JAVA or TOMCAT?

Thanks in advance.

[Enrico_F]

Not sure what you mean by "system descriptors" but you can get FileDescriptor counts very easily via JMX and the java.lang.OperatingSystem MBean.

Attached is a custom JMX plugin that determines OpenFileDescriptorCount and MaxFileDescriptorCount for any Java process:

custom.jmx.CreatedPlugin_FileDescriptor1562237850889.zip

[Piotr_Meller · Accepted solution]

Dear Andrii,

please replace the processTypeNames property by the technologies property in the form:

"technologies": [ "TOMCAT" ]

The value of the technologies can be taken from the UI - on the process level you can find 'Main technology' property for the process, see the attached snapshot:

You can also find this info in Activation tips of Plugin life cycle in the most recent documentation available in our SDK.

Best regards,

Peter