I wanted to invoke JMX operations from the Ant tasks. However finding usable ant tasks library as well as the usage was rather tricky. So let me share my experience to make things easier for others.
Ant tasks for JMX operations
I decided to follow Tomcat documentation and used ant tasks distributed with tomcat.
Just for the record the usage is not restricted to Tomcat deployed JMX mBeans. For me it worked for java process accessible via JConsole via Remote connection.
Retrieving the library
- As I wanted to get the latest version I used maven central repository “search by classname” feature and searched for:
org.apache.catalina.ant.jmx.JMXAccessorTask(see the query) - afterwards I went for the tomcat 8 jar file (called
tomcat-catalina-ant-8.0.8.jar) - and just copyied the latest available to my
$ANT_HOME/libdir.
Usage
I didn’t have a chance (or motivation?) to check all the tasks available, the full list of tasks available can be seen in the zipped file: org/apache/catalina/ant/jmx/antlib.xml, following were present for me:
<typedef
name="open"
classname="org.apache.catalina.ant.jmx.JMXAccessorTask" />
<typedef
name="set"
classname="org.apache.catalina.ant.jmx.JMXAccessorSetTask" />
<typedef
name="get"
classname="org.apache.catalina.ant.jmx.JMXAccessorGetTask" />
<typedef
name="invoke"
classname="org.apache.catalina.ant.jmx.JMXAccessorInvokeTask" />
<typedef
name="query"
classname="org.apache.catalina.ant.jmx.JMXAccessorQueryTask" />
<typedef
name="create"
classname="org.apache.catalina.ant.jmx.JMXAccessorCreateTask" />
<typedef
name="unregister"
classname="org.apache.catalina.ant.jmx.JMXAccessorUnregisterTask" />
<typedef
name="equals"
classname="org.apache.catalina.ant.jmx.JMXAccessorEqualsCondition" />
<typedef
name="condition"
classname="org.apache.catalina.ant.jmx.JMXAccessorCondition" />out of these, I gave following a try:
org.apache.catalina.ant.jmx.JMXAccessorTask
org.apache.catalina.ant.jmx.JMXAccessorInvokeTask
org.apache.catalina.ant.jmx.JMXAccessorQueryTaskFor the demonstration purposes I’m using Glassfish 4.0.
Example: Listing JMX MBeans
Let’s assume we want to retrieve the MBean by name (namely: java.lang:type=Memory). Please note username and password were not required for access (otherwise they should be specified via respective properties).
Noteworthy here is the resultproperty, which could hold array from which we could get a name. So having in ant build script:
<typedef
name="jmxQuery"
classname="org.apache.catalina.ant.jmx.JMXAccessorQueryTask" />
<jmxQuery
host="localhost"
port="8686"
echo="true"
name="java.lang:type=Memory"
resultproperty="memory" />
<echo>Retrieved MBeans count: ${memory.Length}</echo>
<echo>The 1.st one has name: ${memory.0.Name}</echo>results for me in following output:
[jmxQuery] memory.Length=1
[jmxQuery] memory.0.Name=java.lang:type=Memory
[echo] Retrieved MBeans count: 1
[echo] The 1.st one has name: java.lang:type=MemoryExample: Invoking operation via JMX
Here is a 2 step approach required:
- connect to remote server via JMX and afterwards
- invoke the operation on the particular MBean.
For demonstration purposes, let’s assume we want to call garbage collection (via invoking operation: gc() on MBean named: java.lang:type=Memory)
Sample ant build file chunk does the job (please note ref property value that has to be the same across these 2 tasks):
<typedef
name="jmxOpen"
classname="org.apache.catalina.ant.jmx.JMXAccessorTask" />
<typedef
name="jmxInvoke"
classname="org.apache.catalina.ant.jmx.JMXAccessorInvokeTask" />
<jmxOpen
host="localhost"
port="8686"
ref="glassfish"
failOnError="true" />
<jmxInvoke
name="java.lang:type=Memory"
operation="gc"
echo="true"
delimiter=" "
failOnError="true"
ref="glassfish" />Further information
For more details, I recommend reading the official Tomcat documentation as well as Javadocs.
