BSF detector

The BSF Detector lets you run arbitrary scripts using the Bean Scripting Framework to determine the existence of a service. This can be a script written in any of the languages BSF supports. The only requirement is that the script returns the string OK if it passes.

The BSF Detector passes the map, ip_addr, svc_name, and results variables as beans to the script.

Detector facts

Implementation

org.opennms.netmgt.provision.detector.bsf.BSFDetector

Configuration and Use

Table 1. Parameters for the BSF detector
Parameter Description Required Default value

fileName

The path to the file on the OpenNMS server which contains the BSF-compatible script to run.

optional

langClass

The short name of the language the script is written in. Choices: jython, beanshell, groovy, etc.

optional

bsfEngine

The BSF engine to use when running the script. Choices:

* bsh.util.BeanShellBSFEngine * org.codehaus.groovy.bsf.GroovyEngine * org.apache.bsf.engines.jython.JythonEngine

optional

fileExtensions

A comma-separated list of file extensions to consider a valid script for this BSF instance.

optional

runType

Mode to run the BSF script. Choices:

* eval - expects the script to print the OK/NOK status for validation * exec - expects the script to manipulate the provided results hashmap directly

optional

eval

Avoid non-character names for parameters to avoid problems in the script languages.

Timeout and Retry

The BSFDetector does not perform any timeout or retry processing on its own. If you require retry and/or timeout behavior, you must implement it in the script itself.

Requirements for the script (run-types)

Depending on the run-type, the script must provide its results in different ways. For minimal scripts with simple logic, a run-type of eval is the easiest option. Scripts running in eval mode must return a string matching a status code of OK or NOK.

A script with more than one line of logic requires a run-type of exec. Scripts running in exec mode need not return anything, but they have to add a status entry with a status code to the results object. Additionally, the results object can also carry a "reason":"message" entry that is used in non OK states.

Commonly used language settings

The BSF detector supports many languages. The following table provides the required setup for commonly used languages.

Table 2. BSF language setups
Language lang-class bsf-engine required library

BeanShell

beanshell

bsh.util.BeanShellBSFEngine

supported by default

Groovy

groovy

org.codehaus.groovy.bsf.GroovyEngine

groovy-all-[version].jar

Jython

jython

org.apache.bsf.engines.jython.JythonEngine

jython-[version].jar

Example configurations

BeanShell example

BeanShell example
<detector name="MinimalBeanShell" class="org.opennms.netmgt.provision.detector.bsf.BSFDetector">
    <parameter key="bsfEngine" value="bsh.util.BeanShellBSFEngine"/>
    <parameter key="langClass" value="beanshell"/>
    <parameter key="fileName" value="/opt/opennms/etc/scripts/MinimalBeanShell.bsh"/>
    <parameter key="runType" value="eval"/>
</detector>
BeanShell example MinimalBeanShell.bsh script file
File testFile = new File("/tmp/TestFile");
if (testFile.exists()) {
  return "OK";
} else {
  results.put("reason", "file does not exist");
  return "NOK";
}

Groovy example

Groovy example for run-type eval
<detector name="MinimalGroovy" class="org.opennms.netmgt.provision.detector.bsf.BSFDetector">
    <parameter key="bsfEngine" value="org.codehaus.groovy.bsf.GroovyEngine"/>
    <parameter key="langClass" value="groovy"/>
    <parameter key="fileName" value="/opt/opennms/etc/scripts/MinimalGroovy.groovy"/>
    <parameter key="runType" value="eval"/>
</detector>
Groovy example MinimalGroovy.groovy script file for run-type eval
File testFile = new File("/tmp/TestFile");
if (testFile.exists()) {
  return "OK";
} else {
  results.put("reason", "file does not exist");
  return "NOK";
}
Groovy example for run-type exec
<detector name="MinimalGroovy" class="org.opennms.netmgt.provision.detector.bsf.BSFDetector">
    <parameter key="bsfEngine" value="org.codehaus.groovy.bsf.GroovyEngine"/>
    <parameter key="langClass" value="groovy"/>
    <parameter key="fileName" value="/opt/opennms/etc/scripts/MinimalGroovy.groovy"/>
    <parameter key="runType" value="exec"/>
</detector>
Groovy example MinimalGroovy.groovy script file for run-type exec
def testFile = new File("/tmp/TestFile");
if (testFile.exists()) {
  results.put("status", "OK")
} else {
  results.put("reason", "file does not exist");
  results.put("status", "NOK");
}

Jython example

The Jython (Java implementation of Python) language requires an additional library. Copy a compatible jython-x.y.z.jar into the opennms/lib folder and restart Meridian to make Jython available for the BSF Detector.

Jython example for run-type exec
<detector name="MinimalJython" class="org.opennms.netmgt.provision.detector.bsf.BSFDetector">
    <parameter key="bsfEngine" value="org.apache.bsf.engines.jython.JythonEngine"/>
    <parameter key="langClass" value="jython"/>
    <parameter key="fileName" value="/opt/opennms/etc/scripts/MinimalJython.py"/>
    <parameter key="runType" value="exec"/>
</detector>
Jython example MinimalJython.py script file for run-type exec
from java.io import File

if (File("/tmp/TestFile").exists()):
        results.put("status", "OK")
else:
        results.put("reason", "file does not exist")
        results.put("status", "NOK")
We have to use a run type of exec here because Jython chokes on the import keyword in eval mode.