My colleague Andrew tried to post this, but I haven't seen it appear on
the list yet, so I'm sending it out while he does whatever he needs to
do to verify his account...
Hi,
I have a specific error I need help with, but I may also be
approaching the problem incorrectly, so more general advice also
appreciated. Sorry for the length of this email - the questions are
at the end, after all the background data.
(this is all with Camel 2.23.1, OpenJDK 1.8.0_111-b15, CentOS 7.2)
I want to read the local JVM heap usage and write it to a file (the
final task is to write a variety of values for analysis later - the
client has some problem that occurs from time to time and they want
some way of looking back and trying to work out what happened).
I have the following Spring XML config:
<?xml version="1.0" encoding="UTF-8"?>
<beans ...>
<camelContext xmlns="http://camel.apache.org/schema/spring";>
<route>
<from
uri="jmx:platform?objectDomain=java.lang&key.type=Memory&observedAttribute=HeapMemoryUsage&monitorType=gauge&thresholdHigh=0&thresholdLow=0&notifyHigh=True"/>
<log message="Got something"/>
<to uri="file:target/messages/dump"/>
</route>
</camelContext>
</beans>
The important part is the URI:
jmx:platform?objectDomain=java.lang&
key.type=Memory&
observedAttribute=HeapMemoryUsage&
monitorType=gauge&
thresholdHigh=0
thresholdLow=0&
notifyHigh=True
This is giving the error (returned as an XML message):
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<MonitorNotification xmlns="urn:org.apache.camel.component:jmx">
<source>java.lang:name=camel-jmx-monitor-613d8391-408a-4677-9687-afcbf434d7bc</source>
<message>The observed attribute value does not implement the
Comparable interface.</message>
<sequence>0</sequence>
<timestamp>1548695162038</timestamp>
<dateTime>2019-01-28T14:06:02.038-03:00</dateTime>
<type>jmx.monitor.error.type</type>
<derivedGauge>null</derivedGauge>
<observedAttribute>HeapMemoryUsage</observedAttribute>
<observedObject>java.lang:type=Memory</observedObject>
<trigger>null</trigger>
</MonitorNotification>
I suspect this is because the HeapMemoryUsage attribute is of type
javax.management.openmbean.CompositeData.
So, finally, my questions are:
* How do I access structured data like this?
* If I just want the values every X seconds, can I just poll for
values?
* Should I be doing something else? Like maybe configuring my own
notification? If so, is there some guide for dummies? And can
this be automated for monitoring many different valeus?
Thanks,
Andrew
Also:
Following
https://docs.oracle.com/javase/8/docs/api/javax/management/monitor/package-summary.html
I tried to use an observedAttribute value of "HeapMemoryUsage.used",
but this gives the error:
javax.management.AttributeNotFoundException: No such attribute:
HeapMemoryUsage.used
at com.sun.jmx.mbeanserver.PerInterface.getAttribute
(PerInterface.java:81)
at com.sun.jmx.mbeanserver.MBeanSupport.getAttribute
(MBeanSupport.java:206)
at javax.management.StandardMBean.getAttribute (StandardMBean.java:372)
at
com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.getAttribute
(DefaultMBeanServerInterceptor.java:647)
at com.sun.jmx.mbeanserver.JmxMBeanServer.getAttribute
(JmxMBeanServer.java:678)
at
org.apache.camel.component.jmx.JMXMonitorConsumer.convertNumberToAttributeType
(JMXMonitorConsumer.java:110)
...
Which seems odd :(
