Filip Hanik - Dev Lists wrote:
Is the idea here to communicate the Tomcat server state to httpd using
multicast?
Yes.
For that, you could simply build the feature set into
org.apache.catalina.ha where you can send multicast packets, where you
already have heart beat information etc.
Well the feature doesn't require a clustered tomcat.
So going that route, why not use code, or at least copy/paste the code
where we fixed the bugs :)
However, if I was to voice my opinion, I think you can easily transfer
all the information you need as HTTP headers, and hence you could do so
with minimal coding effort.
Multicast seems funky, since the httpd server already talks TCP/HTTP/AJP
to tomcat. Why another transport protocol. Multicast is usually
disallowed through firewalls, which means the very common scenario of
having httpd in the DMZ and tomcat on the other side of the firewall
will not work.
The idea is to use this code with the already existing code in
httpd-trunk and the httpd module uses multicast.
But yes I agree that the idea to use TCP/HTTP is a good option too but
that requires more code on the httpd side.
Cheers
Jean-Frederic
Filip
jean-frederic clere wrote:
Rainer Jung wrote:
A few comments inline.
On 06.04.2009 17:09, jfcl...@apache.org wrote:
Author: jfclere
Date: Mon Apr 6 15:09:19 2009
New Revision: 762374
URL: http://svn.apache.org/viewvc?rev=762374&view=rev
Log:
First support for httpd-trunk heartbeat logic.
Added:
tomcat/trunk/java/org/apache/catalina/cluster/
tomcat/trunk/java/org/apache/catalina/cluster/CollectedInfo.java
tomcat/trunk/java/org/apache/catalina/cluster/HeartbeatListener.java
Modified:
tomcat/trunk/build.xml
Modified: tomcat/trunk/build.xml
URL:
http://svn.apache.org/viewvc/tomcat/trunk/build.xml?rev=762374&r1=762373&r2=762374&view=diff
==============================================================================
--- tomcat/trunk/build.xml (original)
+++ tomcat/trunk/build.xml Mon Apr 6 15:09:19 2009
@@ -204,7 +204,6 @@
<include name="org/apache/naming/**" />
<!-- Modules -->
<exclude name="org/apache/catalina/ant/**" />
- <exclude name="org/apache/catalina/cluster/**" />
<exclude name="org/apache/catalina/ha/**" />
<exclude name="org/apache/catalina/mbeans/JmxRemote*" />
<exclude name="org/apache/catalina/tribes/**" />
See below concerning the package name.
Added: tomcat/trunk/java/org/apache/catalina/cluster/CollectedInfo.java
URL:
http://svn.apache.org/viewvc/tomcat/trunk/java/org/apache/catalina/cluster/CollectedInfo.java?rev=762374&view=auto
==============================================================================
--- tomcat/trunk/java/org/apache/catalina/cluster/CollectedInfo.java
(added)
+++ tomcat/trunk/java/org/apache/catalina/cluster/CollectedInfo.java
Mon Apr 6 15:09:19 2009
...
+package org.apache.catalina.cluster;
Should we really reuse this package name? Until TC 5.5 that was the old
cluster, and the package name is still in use for the same classes in
the oacc sandbox.
Ok... What about backend?
+
+/* for MBean to read ready and busy */
+
+import javax.management.MBeanServer;
+import javax.management.ObjectName;
+import javax.management.ObjectInstance;
+import java.util.Enumeration;
+import java.util.Iterator;
+import java.util.Set;
+
+import org.apache.tomcat.util.modeler.Registry;
+import org.apache.juli.logging.Log;
+import org.apache.juli.logging.LogFactory;
+
+/*
+ * Listener to provider informations to mod_heartbeat.c
+ * *msg_format = "v=%u&ready=%u&busy=%u"; (message to send).
+ * send the muticast merssage using the format...
+ * what about the bind(IP. port) only IP makes sense (for the moment).
+ * BTW:v = version :-)
+ */
+public class CollectedInfo {
+
+ /* Collect info via JMX */
+ protected MBeanServer mBeanServer = null;
+ protected ObjectName objName = null;
+
+ int ready;
+ int busy;
+
+ public CollectedInfo(String host, int port) throws Exception {
+ init(host, port);
+ }
+ public void init(String host, int port) throws Exception {
+ String sport = Integer.toString(port);
+ mBeanServer = Registry.getRegistry(null,
null).getMBeanServer();
+ String onStr = "*:type=ThreadPool,*";
Use a constant for this string?
+ ObjectName objectName = new ObjectName(onStr);
+ Set set = mBeanServer.queryMBeans(objectName, null);
+ Iterator<ObjectInstance> iterator = set.iterator();
+ while (iterator.hasNext()) {
+ ObjectInstance oi = iterator.next();
+ objName = oi.getObjectName();
+ String name = objName.getKeyProperty("name");
+ /* Name are:
+ * http-8080
+ * jk-10.33.144.3-8009
+ * jk-jfcpc%2F10.33.144.3-8009
+ */
+ if (port==0 && host==null)
+ break; /* Take the first one */
+ String [] elenames = name.split("-");
+ if (elenames[elenames.length-1].compareTo(sport) != 0)
+ continue; /* port doesn't match */
+ if (host==null)
+ break; /* Only port done */
+ String [] shosts = elenames[1].split("%2F");
+ if (shosts[0].compareTo(host) == 0)
+ break; /* Done port and host are the expected ones */
+ }
+ if (objName == null)
+ throw(new Exception("Can't find connector for " + host
+ ":" + sport));
+ + }
+
+ public void refresh() throws Exception {
+ if (mBeanServer == null || objName == null) {
+ throw(new Exception("Not initialized!!!"));
+ }
+ Integer imax = (Integer) mBeanServer.getAttribute(objName,
"maxThreads");
+
+ // the currentThreadCount could be 0 before the threads are
created...
+ // Integer iready = (Integer)
mBeanServer.getAttribute(objName, "currentThreadCount");
+
+ Integer ibusy = (Integer)
mBeanServer.getAttribute(objName, "currentThreadsBusy");
+
+ busy = ibusy.intValue();
+ ready = imax.intValue() - ibusy;
+ }
+}
Added:
tomcat/trunk/java/org/apache/catalina/cluster/HeartbeatListener.java
URL:
http://svn.apache.org/viewvc/tomcat/trunk/java/org/apache/catalina/cluster/HeartbeatListener.java?rev=762374&view=auto
==============================================================================
---
tomcat/trunk/java/org/apache/catalina/cluster/HeartbeatListener.java
(added)
+++
tomcat/trunk/java/org/apache/catalina/cluster/HeartbeatListener.java
Mon Apr 6 15:09:19 2009
...
+package org.apache.catalina.cluster;
See above.
+
+import org.apache.catalina.ContainerEvent;
+import org.apache.catalina.ContainerListener;
+import org.apache.catalina.Engine;
+import org.apache.catalina.Lifecycle;
+import org.apache.catalina.LifecycleEvent;
+import org.apache.catalina.LifecycleListener;
+import org.apache.juli.logging.Log;
+import org.apache.juli.logging.LogFactory;
+
+import org.apache.catalina.connector.Connector;
+
+import java.net.MulticastSocket;
+import java.net.InetAddress;
+import java.net.DatagramPacket;
+import java.io.UnsupportedEncodingException;
+
+import org.apache.tomcat.util.modeler.Registry;
+
+/*
+ * Listener to provider informations to mod_heartbeat.c
+ * *msg_format = "v=%u&ready=%u&busy=%u"; (message to send).
+ * send the muticast merssage using the format...
+ * what about the bind(IP. port) only IP makes sense (for the moment).
+ * BTW:v = version :-)
+ */
+public class HeartbeatListener
+ implements LifecycleListener, ContainerListener {
+
+ public static Log log =
LogFactory.getLog(HeartbeatListener.class);
public?
fixed.
+
+ /* To allow to select the connector */
+ int port = 0;
+ String host = null;
+ public void setHost(String host) { this.host = host; }
+ public void setPort(int port) { this.port = port; }
Will we need getters as well?
Probably :-)
+
+ /* for multicasting stuff */
+ MulticastSocket s = null;
+ InetAddress group = null;
+ String ip = "224.0.1.105"; /* Multicast IP */
+ int multiport = 23364; /* Multicast Port */
I assume those two will be configurable in a future version ...
? They are already setGroup() and setPort().
+
+ public void setGroup(String ip) { this.ip = ip; }
+ public void setMultiport(int multiport) { this.multiport =
multiport; }
+
+ private CollectedInfo coll = null;
+
+ public void containerEvent(ContainerEvent event) {
+ }
+
+ public void lifecycleEvent(LifecycleEvent event) {
+ Object source = event.getLifecycle();
+ if (Lifecycle.PERIODIC_EVENT.equals(event.getType())) {
+ if (s == null) {
+ try {
+ group = InetAddress.getByName(ip);
+ s = new MulticastSocket(port);
+ s.setTimeToLive(16);
Use a constant instead of "16"?
I have added a get/set for Ttl.
+ s.joinGroup(group);
+ } catch (Exception ex) {
+ log.error("Unable to use multicast: " + ex);
+ s = null;
+ return;
+ } + }
+// * *msg_format = "v=%u&ready=%u&busy=%u"; (message to send).
+// v = version (1)
+// ready & ready are read from the scoreboard in httpd.
+// Endpoint ( getCurrentThreadsBusy ) ( getMaxThreads )
What's the use of these comments?
Oops.
+ if (coll == null) {
+ try {
+ coll = new CollectedInfo(host, port);
+ } catch (Exception ex) {
+ log.error("Unable to initialize info
collection: " + ex);
+ coll = null;
+ return;
+ } + }
+ try {
+ coll.refresh();
+ } catch (Exception ex) {
+ log.error("Unable to collect load information: " +
ex);
+ coll = null;
+ return;
+ }
+ String output = new String();
+ output = "v=1&ready=" + coll.ready + "&busy=" + coll.busy;
You might want to use string constants for the param names.
+ byte[] buf;
+ try {
+ buf = output.getBytes("US-ASCII");
+ } catch (UnsupportedEncodingException ex) {
+ buf = output.getBytes();
+ }
+ DatagramPacket data = new DatagramPacket(buf,
buf.length, group, multiport);
+ try {
+ s.send(data);
+ } catch (Exception ex) {
+ log.error("Unable to send colllected load
information: " + ex);
+ System.out.println(ex);
Please no System.out.println(). Left over from debugging ;)
Oops.
Cheers
Jean-Frederic
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