JMX is the defacto standard which is used for monitoring all applications which have anything to do with the Java virual environment. Given that Groovy sits directly on top of Java, Groovy can leverage the tremendous amount of work already done for JMX with Java.
Monitoring the JVM
One can use the standard classes available in java.lang.management for carrying out the monitoring of the JVM. The following code example shows how this can be done.
import java.lang.management.*
def os = ManagementFactory.operatingSystemMXBean
println """OPERATING SYSTEM:
\tOS architecture = $os.arch
\tOS name = $os.name
\tOS version = $os.version
\tOS processors = $os.availableProcessors
"""
def rt = ManagementFactory.runtimeMXBean
println """RUNTIME:
\tRuntime name = $rt.name
\tRuntime spec name = $rt.specName
\tRuntime vendor = $rt.specVendor
\tRuntime spec version = $rt.specVersion
\tRuntime management spec version = $rt.managementSpecVersion
"""
def mem = ManagementFactory.memoryMXBean
def heapUsage = mem.heapMemoryUsage
def nonHeapUsage = mem.nonHeapMemoryUsage
println """MEMORY:
HEAP STORAGE:
\tMemory committed = $heapUsage.committed
\tMemory init = $heapUsage.init
\tMemory max = $heapUsage.max
\tMemory used = $heapUsage.used NON-HEAP STORAGE:
\tNon-heap memory committed = $nonHeapUsage.committed
\tNon-heap memory init = $nonHeapUsage.init
\tNon-heap memory max = $nonHeapUsage.max
\tNon-heap memory used = $nonHeapUsage.used
"""
println "GARBAGE COLLECTION:"
ManagementFactory.garbageCollectorMXBeans.each { gc ->
println "\tname = $gc.name"
println "\t\tcollection count = $gc.collectionCount"
println "\t\tcollection time = $gc.collectionTime"
String[] mpoolNames = gc.memoryPoolNames
mpoolNames.each {
mpoolName -> println "\t\tmpool name = $mpoolName"
}
}
When the code is executed, the output will vary depending on the system on which the code is run. A sample of the output is given below.
OPERATING SYSTEM:
OS architecture = x86
OS name = Windows 7
OS version = 6.1
OS processors = 4
RUNTIME:
Runtime name = 5144@Babuli-PC
Runtime spec name = Java Virtual Machine Specification
Runtime vendor = Oracle Corporation
Runtime spec version = 1.7
Runtime management spec version = 1.2
MEMORY:
HEAP STORAGE:
Memory committed = 16252928
Memory init = 16777216
Memory max = 259522560
Memory used = 7355840
NON-HEAP STORAGE:
Non-heap memory committed = 37715968
Non-heap memory init = 35815424
Non-heap memory max = 123731968
Non-heap memory used = 18532232
GARBAGE COLLECTION:
name = Copy
collection count = 15
collection time = 47
mpool name = Eden Space
mpool name = Survivor Space
name = MarkSweepCompact
collection count = 0
collection time = 0
mpool name = Eden Space
mpool name = Survivor Space
mpool name = Tenured Gen
mpool name = Perm Gen
mpool name = Perm Gen [shared-ro]
mpool name = Perm Gen [shared-rw]
Monitoring Tomcat
In order to monitor tomcat, the following parameter should be set when tomcat is started −
set JAVA_OPTS = -Dcom.sun.management.jmxremote Dcom.sun.management.jmxremote.port = 9004\ -Dcom.sun.management.jmxremote.authenticate=false Dcom.sun.management.jmxremote.ssl = false
The following code uses JMX to discover the available MBeans in the running Tomcat, determine which are the web modules and extract the processing time for each web module.
import groovy.swing.SwingBuilder
import javax.management.ObjectName
import javax.management.remote.JMXConnectorFactory as JmxFactory
import javax.management.remote.JMXServiceURL as JmxUrl
import javax.swing.WindowConstants as WC
import org.jfree.chart.ChartFactory
import org.jfree.data.category.DefaultCategoryDataset as Dataset
import org.jfree.chart.plot.PlotOrientation as Orientation
def serverUrl = 'service:jmx:rmi:///jndi/rmi://localhost:9004/jmxrmi'
def server = JmxFactory.connect(new JmxUrl(serverUrl)).MBeanServerConnection
def serverInfo = new GroovyMBean(server, 'Catalina:type = Server').serverInfo
println "Connected to: $serverInfo"
def query = new ObjectName('Catalina:*')
String[] allNames = server.queryNames(query, null)
def modules = allNames.findAll { name ->
name.contains('j2eeType=WebModule')
}.collect{ new GroovyMBean(server, it) }
println "Found ${modules.size()} web modules. Processing ..."
def dataset = new Dataset()
modules.each { m ->
println m.name()
dataset.addValue m.processingTime, 0, m.path
}
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