These are my notes on using ActiveMQ.
Why is there no admin application?
When installing ActiveMQ with the =apt-get=, there's no admin application:
# apt-get install activemq
$ curl http://127.0.0.1:61616/admin
It's because it's not enabled per default. To enable it:
# zcat /usr/share/doc/activemq/examples/conf/jetty.xml.gz > \
/etc/activemq/instances-available/main/jetty.xml
You can now refer to it from your activemq.xml:
<beans>
<!-- to get the admin console -->
<import resource="jetty.xml"/>
</beans>
You may then run into this problem because the DEB package doesn't have all the ActiveMQ features:
2014-01-02 13:28:38,065 | ERROR | Failed to load: class path resource
[activemq.xml], reason: Failed to load type:
org.eclipse.jetty.security.HashLoginService. Reason:
java.lang.ClassNotFoundException:
org.eclipse.jetty.security.HashLoginService; nested exception is
java.lang.ClassNotFoundException:
org.eclipse.jetty.security.HashLoginService |
org.apache.activemq.xbean.XBeanBrokerFactory | main
org.springframework.beans.factory.BeanDefinitionStoreException: Failed
to load type: org.eclipse.jetty.security.HashLoginService. Reason:
java.lang.ClassNotFoundException:
org.eclipse.jetty.security.HashLoginService; nested exception is
java.lang.ClassNotFoundException:
org.eclipse.jetty.security.HashLoginService
I therefore used the JARs from the vanilla ActiveMQ distribution. I didn't want to overwrite, or remove, any of the JARs that came with the Debian packages, instead, I modified the init script so that the it used the downloaded tarball instead of the package installed version.
$ diff -w activemq.orig activemq
21c21,23
< ACTIVEMQ_JAR=/usr/share/activemq/bin/run.jar
---
> activemq_home=/opt/activemq
> ACTIVEMQ_JAR=${activemq_home}/bin/run.jar
113c115
< export ACTIVEMQ_HOME=/usr/share/activemq
---
> export ACTIVEMQ_HOME=${activemq_home}
209c211
< export ACTIVEMQ_HOME=/usr/share/activemq
---
> export ACTIVEMQ_HOME=${activemq_home}
Admin console says Could not resolve placeholder 'activemq.username'
2014-01-02 13:46:25,366 | WARN | Failed startup of context
o.e.j.w.WebAppContext{/admin,file:/opt/apache-activemq-5.6.0/webapps/admin/}
| org.eclipse.jetty.webapp.WebAppContext | main
org.springframework.beans.factory.BeanDefinitionStoreException:
Invalid bean definition with name 'connectionFactory' defined in
ServletContext resource [/WEB-INF/webconsole-embedded.xml]: Could not
resolve placeholder 'activemq.username'
This was because I didn't have the activemq.username and password in
my activemq.xml:
# cat > /etc/activemq/instances-available/main/credentials.properties <<EOF
activemq.username=foo
activemq.password=bar
EOF
ERROR on start up complaining about size
2014-01-02 13:08:57,919 | ERROR | Temporary Store limit is 50000 mb,
whilst the temporary data directory:
/var/lib/activemq/main/data/localhost/tmp_storage only has 5656 mb of
usable space | org.apache.activemq.broker.BrokerService | main
Cannot send, channel has already failed
2014-01-02 13:01:02,927 | DEBUG | Reason: org.apache.activemq.transport.InactivityIOException:
Cannot send, channel has already failed: tcp://127.0.0.1:34528 |
org.apache.activemq.broker.TransportConnector | ActiveMQ Task-19
org.apache.activemq.transport.InactivityIOException: Cannot send, channel has already failed:
tcp://127.0.0.1:34528
at org.apache.activemq.transport.AbstractInactivityMonitor.doOnewaySend(
AbstractInactivityMonitor.java:255)
at org.apache.activemq.transport.AbstractInactivityMonitor.oneway(
AbstractInactivityMonitor.java:244)
at org.apache.activemq.transport.WireFormatNegotiator.sendWireFormat(
WireFormatNegotiator.java:168)
at org.apache.activemq.transport.WireFormatNegotiator.sendWireFormat(
WireFormatNegotiator.java:84)
at org.apache.activemq.transport.WireFormatNegotiator.start(
WireFormatNegotiator.java:74)
at org.apache.activemq.transport.TransportFilter.start(
TransportFilter.java:58)
at org.apache.activemq.broeker.TransportConnection.start(
TransportConnection.java:914)
at org.apache.activemq.broker.TransportConnector$1$1.run(
TransportConnector.java:227)
at java.lang.Thread.run(Thread.java:724)
What's the difference between a topic and a subject?
Looking at this Java-snippet, they seem to mean the same thing:
String subject="topic.jay";
[..]
Destination destination = new ActiveMQTopic(subject);
Need to confirm this, though.
