An Axis2 Service to Log the incoming message

Java class is:

 package org.wso2.logservice;  
 import org.apache.commons.logging.Log;  
 import org.apache.commons.logging.LogFactory;  
 public class LogService{  
   private static final Log log = LogFactory.getLog(LogService.class);  
   public void LogAndDrop (String incoming) {     
     log.info("The message is: "+ incoming);  
   }  
   public String LogAndAck (String incoming) {  
     log.info("The message is: "+ incoming);  
     return "Logged: "+ incoming;  
   }  
 }  

Use this class and build an axis2 service.
Then you can deploy the service in WSO2 Application Server and invoke.

While invoking with a String value you will be able to notice that the message you sent will be logged in the wso2carbon.log as

 TID: [0] [AS] [2013-07-11 10:42:23,686] INFO {org.wso2.logservice.LogService} - The message is: Logging is what? Good ! {org.wso2.logservice.LogService}  
 TID: [0] [AS] [2013-07-11 10:42:37,993] INFO {org.wso2.logservice.LogService} - The message is: Logging and getting a response is what? Goood ! {org.wso2.logservice.LogService}  

WSO2 ESB, MB integration to serve a backend axis2service with more than one JMS queues to ensure the speed and the integrity

WSO2 ESB's JMS Message Store implementation can be used to store incoming messages in a queue and serve a backend service without having to worry about the integrity of the messages.

In a simple scenario it is possible to implement a Proxy service which the client sees and calls to, a message store which stores those messages in a JMS queue and a message processor which fetches those messages and send to the defined endpoint.

We can implement a scenario which uses more than one queues and more than one message stores to put messages into those queues and more than one message processors to fetch from queues and serves one backend endpoint. Here we will have to use more than one proxy service in ESB and the requests coming in can be load balanced to which proxy it should go and which ESB node it should go.

Here I'm using three proxy services in two ESB nodes. The load balancing to each proxy needs to be done from the client side. But the load balancing to each ESB node will be happened by the ELB.

First you have to configure a ESB Cluster load balanced by a WSO2 ELB and with JMS transport enabled with a WSO2 MB. After that you can use the following synapse configurations to implement the scenario.

One set of Proxy, Store, Processor, Endpoint configuration of ESB node 1;

Proxy; 

 <?xml version="1.0" encoding="UTF-8"?>  
 <proxy xmlns="http://ws.apache.org/ns/synapse"  
     name="Proxy1"  
     transports="https http"  
     startOnLoad="true"  
     trace="disable">  
   <description/>  
   <target>  
    <inSequence>  
      <property name="FORCE_SC_ACCEPTED" value="true" scope="axis2"/>  
      <property name="OUT_ONLY" value="true"/>  
      <property name="target.endpoint" value="logndrop"/>  
      <store messageStore="JMSMS"/>  
    </inSequence>  
   </target>  
 </proxy>  

Endpoint;

 <?xml version="1.0" encoding="UTF-8"?>  
 <endpoint xmlns="http://ws.apache.org/ns/synapse" name="logndrop">  
   <address uri="http://localhost:9773/as/services/LognDrop"/>  
 </endpoint>  

Message Store;
 

 <?xml version="1.0" encoding="UTF-8"?>  
 <messageStore xmlns="http://ws.apache.org/ns/synapse"  
        class="org.wso2.carbon.message.store.persistence.jms.JMSMessageStore"  
        name="JMSMS">  
   <parameter name="java.naming.factory.initial">org.wso2.andes.jndi.PropertiesFileInitialContextFactory</parameter>  
   <parameter name="store.jms.cache.connection">false</parameter>  
   <parameter name="java.naming.provider.url">repository/conf/jndi.properties</parameter>  
   <parameter name="store.jms.destination">JMSMS</parameter>  
   <parameter name="store.jms.JMSSpecVersion">1.1</parameter>  
 </messageStore>  

Message Processor;

 <?xml version="1.0" encoding="UTF-8"?>  
 <messageProcessor xmlns="http://ws.apache.org/ns/synapse"  
          class="org.apache.synapse.message.processors.forward.ScheduledMessageForwardingProcessor"  
          name="Processor1"  
          messageStore="JMSMS">  
   <parameter name="max.delivery.attempts">4</parameter>  
   <parameter name="interval">4000</parameter>  
 </messageProcessor>  

The other set of Proxy, Store, Processor, Endpoint configuration of ESB node 1;

Proxy;

 <?xml version="1.0" encoding="UTF-8"?>  
 <proxy xmlns="http://ws.apache.org/ns/synapse"  
     name="Proxy2"  
     transports="https http"  
     startOnLoad="true"  
     trace="disable">  
   <description/>  
   <target>  
    <inSequence>  
      <property name="FORCE_SC_ACCEPTED" value="true" scope="axis2"/>  
      <property name="OUT_ONLY" value="true"/>  
      <property name="target.endpoint" value="logndrop"/>  
      <store messageStore="JMSMS2"/>  
    </inSequence>  
   </target>  
 </proxy>  

Endpoint; 

 <?xml version="1.0" encoding="UTF-8"?>  
 <endpoint xmlns="http://ws.apache.org/ns/synapse" name="logndrop">  
   <address uri="http://localhost:9773/as/services/LognDrop"/>  
 </endpoint>  

Message Store; 

 <?xml version="1.0" encoding="UTF-8"?>  
 <messageStore xmlns="http://ws.apache.org/ns/synapse"  
        class="org.wso2.carbon.message.store.persistence.jms.JMSMessageStore"  
        name="JMSMS2">  
   <parameter name="java.naming.factory.initial">org.wso2.andes.jndi.PropertiesFileInitialContextFactory</parameter>  
   <parameter name="store.jms.cache.connection">false</parameter>  
   <parameter name="java.naming.provider.url">repository/conf/jndi.properties</parameter>  
   <parameter name="store.jms.JMSSpecVersion">1.1</parameter>  
   <parameter name="store.jms.destination">JMSMS2</parameter>  
 </messageStore>  

Message Processor;

 <?xml version="1.0" encoding="UTF-8"?>  
 <messageProcessor xmlns="http://ws.apache.org/ns/synapse"  
          class="org.apache.synapse.message.processors.forward.ScheduledMessageForwardingProcessor"  
          name="Processor2"  
          messageStore="JMSMS2">  
   <parameter name="max.delivery.attempts">4</parameter>  
   <parameter name="interval">4000</parameter>  
 </messageProcessor>  

This configuration needs to be synced with one other esb node in a esb cluster. The requests needs to be load balanced to each proxies by the client. And each of these messages will be load balanced to each ESB node in the cluster by the ELB. In my implementation I haven't used a ELB so that I had to load balance the requests to each esb nodes too by the client. Also I used three Proxy services, three Message Stores and Three Message Processors which talks to the same backend. Here only two are mentioned.

The backend service is a Axis2 Service which prints the incoming message and forget it.

 public class LognDrop {  
         public void logndrop(String value) {  
             System.out.println("Value is:" + value);  
         }  
 }   

Service can be found at;

https://svn.wso2.org/repos/wso2/trunk/commons/qa/qa-artifacts/app-server/LognDrop.aar

An Apache Jmeter project is the client which sends a string value to the proxy services. So that finally we can see how the requests are processed.
The Jmeter script can be found at;
https://svn.wso2.org/repos/wso2/trunk/commons/qa/qa-artifacts/app-server/jmeter-tests/InvokeLognDrop.jmx

Results;
  
 You can enable DEBUG logs for ESB JMS Message Processors by putting the following entry in {ESB_HOME}/repository/conf/log4j.properties

 #JMS Message Processor log  
 log4j.logger.org.wso2.carbon.jmsms.MSMPLog=DEBUG  

 so that you can see the execution in the ESB side as following;

 [2013-07-10 12:39:42,416] DEBUG - MSMPLog [JMSMS] Storing[1] MessageID:urn:uuid:d3e97693-9b07-46e4-a7c9-4b108965a188  
 [2013-07-10 12:39:42,439] DEBUG - MSMPLog [JMSMS] Storing[2] MessageID:urn:uuid:e9e391cb-3778-4e9e-8490-99d68dea4a9d  
 [2013-07-10 12:39:42,492] DEBUG - MSMPLog [JMSMS2] Storing[1] MessageID:urn:uuid:d0b76a30-9107-4db9-b159-8b70b707d29b  
 [2013-07-10 12:39:42,510] DEBUG - MSMPLog [JMSMS2] Storing[2] MessageID:urn:uuid:7c4579bf-cdb5-4173-a961-36c7cbeb2299  
 [2013-07-10 12:39:42,567] DEBUG - MSMPLog [JMSMS3] Storing[1] MessageID:urn:uuid:289e4073-1199-4805-9c32-46d689902059  
 [2013-07-10 12:39:42,584] DEBUG - MSMPLog [JMSMS3] Storing[2] MessageID:urn:uuid:f942d2c1-14b1-4867-8727-f745af147a6b  
 [2013-07-10 12:39:42,590] DEBUG - MSMPLog [JMSMS] Storing[3] MessageID:urn:uuid:32aa8ac0-470c-4293-8d36-1682df482a2a  
 [2013-07-10 12:39:42,658] DEBUG - MSMPLog [JMSMS] Storing[4] MessageID:urn:uuid:962808ff-19bf-4d86-a4b1-2e7e0b4363ec  
 [2013-07-10 12:39:42,672] DEBUG - MSMPLog [JMSMS2] Storing[3] MessageID:urn:uuid:62b3cfe6-f947-49e2-a43f-a39d09970147  
 [2013-07-10 12:39:42,716] DEBUG - MSMPLog [JMSMS2] Storing[4] MessageID:urn:uuid:d463555f-6955-450a-9b84-d2d2a6749712  
 [2013-07-10 12:39:42,731] DEBUG - MSMPLog [JMSMS3] Storing[3] MessageID:urn:uuid:56221673-e159-4604-8baf-31193fb0536e  
 [2013-07-10 12:39:42,747] DEBUG - MSMPLog [JMSMS] Storing[5] MessageID:urn:uuid:76ad4a31-91f4-4372-a851-2189723c485c  
 [2013-07-10 12:39:42,783] DEBUG - MSMPLog [JMSMS3] Storing[4] MessageID:urn:uuid:087fba00-7d6f-4138-8fa8-06c1549b508a  
 [2013-07-10 12:39:42,845] DEBUG - MSMPLog [JMSMS] Storing[6] MessageID:urn:uuid:5ba9bdba-9ada-48ae-ac33-41bcd22d4b73  
 [2013-07-10 12:39:42,848] DEBUG - MSMPLog [JMSMS2] Storing[5] MessageID:urn:uuid:7af16cc1-ee29-4f16-addc-0d9ae4b51f9b  
 [2013-07-10 12:39:42,921] DEBUG - MSMPLog [JMSMS2] Storing[6] MessageID:urn:uuid:3d802cb7-a029-4a59-b8b3-4c1b1074d4ab  
 [2013-07-10 12:39:42,971] DEBUG - MSMPLog [JMSMS] Storing[7] MessageID:urn:uuid:0dbd1ff5-071f-4d4e-b9df-ede65146cd20  
 [2013-07-10 12:39:42,999] DEBUG - MSMPLog [JMSMS3] Storing[5] MessageID:urn:uuid:19f02a23-6149-4c82-be32-9ec69986a45e  
 [2013-07-10 12:39:43,058] DEBUG - MSMPLog [JMSMS] Storing[8] MessageID:urn:uuid:3307251f-31cb-4690-bb23-224c4fd8d480  
 [2013-07-10 12:39:43,075] DEBUG - MSMPLog [JMSMS3] Storing[6] MessageID:urn:uuid:ba76517e-f4f2-4a5d-81eb-ed6c4f260783  
 [2013-07-10 12:39:43,078] DEBUG - MSMPLog [JMSMS2] Storing[7] MessageID:urn:uuid:3c5aa2fb-ad8c-4f9e-8c4d-222a21d2892f  
 [2013-07-10 12:39:43,150] DEBUG - MSMPLog [JMSMS] Storing[9] MessageID:urn:uuid:a08658be-a5b4-4cc4-a485-b53b86a2d871  
 [2013-07-10 12:39:43,161] DEBUG - MSMPLog [JMSMS3] Storing[7] MessageID:urn:uuid:3a487564-41ff-464a-bca7-6bc83030f03b  
 [2013-07-10 12:39:43,170] DEBUG - MSMPLog [JMSMS2] Storing[8] MessageID:urn:uuid:773b675f-f96f-48b1-a1f9-be31b102a933  
 [2013-07-10 12:39:43,177] DEBUG - MSMPLog [Processor2] Fetched[1] MessageID:urn:uuid:d0b76a30-9107-4db9-b159-8b70b707d29b  
 [2013-07-10 12:39:43,199] DEBUG - MSMPLog [Processor2] Fetched[2] MessageID:urn:uuid:3c121aab-ca24-45ba-a3bb-c727ecfda28a  
 [2013-07-10 12:39:43,227] DEBUG - MSMPLog [JMSMS2] Storing[7] MessageID:urn:uuid:82f95665-c758-4c8e-ae8d-a0db3c389a32  
 [2013-07-10 12:39:43,236] DEBUG - MSMPLog [Processor2] Fetched[3] MessageID:urn:uuid:62b3cfe6-f947-49e2-a43f-a39d09970147  
 [2013-07-10 12:39:43,246] DEBUG - MSMPLog [JMSMS] Storing[10] MessageID:urn:uuid:be8c177b-2483-4db4-8a39-fcf6f6b4793e  
 [2013-07-10 12:39:43,255] DEBUG - MSMPLog [Processor2] Fetched[4] MessageID:urn:uuid:d463555f-6955-450a-9b84-d2d2a6749712  
 [2013-07-10 12:39:43,303] DEBUG - MSMPLog [JMSMS3] Storing[8] MessageID:urn:uuid:91fef3e9-1146-4903-a790-02fee3685f26  
 [2013-07-10 12:39:43,337] DEBUG - MSMPLog [JMSMS2] Storing[6] MessageID:urn:uuid:2b4a76a8-2c6d-4e99-9da7-be5cf207aee1  
 [2013-07-10 12:39:43,348] DEBUG - MSMPLog [JMSMS3] Storing[9] MessageID:urn:uuid:cc754b66-11bf-40f0-b9d8-7ec72ac7397a  
 [2013-07-10 12:39:43,379] DEBUG - MSMPLog [JMSMS3] Storing[10] MessageID:urn:uuid:06bf808e-f35f-4724-ad34-d723d39b7131  
 [2013-07-10 12:39:43,412] DEBUG - MSMPLog [Processor2] Fetched[5] MessageID:urn:uuid:7af16cc1-ee29-4f16-addc-0d9ae4b51f9b  
 [2013-07-10 12:39:43,436] DEBUG - MSMPLog [Processor2] Fetched[6] MessageID:urn:uuid:3d802cb7-a029-4a59-b8b3-4c1b1074d4ab  
 [2013-07-10 12:39:43,455] DEBUG - MSMPLog [Processor2] Fetched[7] MessageID:urn:uuid:3c5aa2fb-ad8c-4f9e-8c4d-222a21d2892f  
 [2013-07-10 12:39:43,835] DEBUG - MSMPLog [Processor1] Fetched[1] MessageID:urn:uuid:1f50e3f1-46aa-470c-bf77-feea4088f32b  
 [2013-07-10 12:39:43,852] DEBUG - MSMPLog [Processor1] Fetched[2] MessageID:urn:uuid:32aa8ac0-470c-4293-8d36-1682df482a2a  
 [2013-07-10 12:39:43,867] DEBUG - MSMPLog [Processor1] Fetched[3] MessageID:urn:uuid:8bb300cb-faa9-45b4-bbd9-1d1e83f5aea7  
 [2013-07-10 12:39:43,878] DEBUG - MSMPLog [Processor1] Fetched[4] MessageID:urn:uuid:2103ba47-77e8-4518-8050-e18b81be62dd  
 [2013-07-10 12:39:43,890] DEBUG - MSMPLog [Processor3] Fetched[1] MessageID:urn:uuid:289e4073-1199-4805-9c32-46d689902059  
 [2013-07-10 12:39:43,893] DEBUG - MSMPLog [Processor1] Fetched[5] MessageID:urn:uuid:ee2b3c05-8a68-40ef-a2f1-be8c12a2a788  
 [2013-07-10 12:39:43,916] DEBUG - MSMPLog [Processor2] Fetched[8] MessageID:urn:uuid:773b675f-f96f-48b1-a1f9-be31b102a933  
 [2013-07-10 12:39:43,938] DEBUG - MSMPLog [Processor3] Fetched[2] MessageID:urn:uuid:b6fdf8eb-24eb-4ff4-8d49-5b58ae4fd38a  
 [2013-07-10 12:39:43,943] DEBUG - MSMPLog [Processor2] Fetched[9] MessageID:urn:uuid:82f95665-c758-4c8e-ae8d-a0db3c389a32  
 [2013-07-10 12:39:43,947] DEBUG - MSMPLog [Processor1] Fetched[6] MessageID:urn:uuid:e24eb516-c99c-4051-af0c-6120e9c9cd01  
 [2013-07-10 12:39:43,960] DEBUG - MSMPLog [Processor3] Fetched[3] MessageID:urn:uuid:56221673-e159-4604-8baf-31193fb0536e  
 [2013-07-10 12:39:43,961] DEBUG - MSMPLog [Processor2] Fetched[10] MessageID:urn:uuid:2b4a76a8-2c6d-4e99-9da7-be5cf207aee1  
 [2013-07-10 12:39:43,967] DEBUG - MSMPLog [Processor1] Fetched[7] MessageID:urn:uuid:909f69a0-44d9-462c-a8f8-1065fe81232d  
 [2013-07-10 12:39:43,974] DEBUG - MSMPLog [Processor3] Fetched[4] MessageID:urn:uuid:087fba00-7d6f-4138-8fa8-06c1549b508a  
 [2013-07-10 12:39:43,979] DEBUG - MSMPLog [Processor1] Fetched[8] MessageID:urn:uuid:54b99480-9976-436f-8aa2-f80d70602433  
 [2013-07-10 12:39:43,985] DEBUG - MSMPLog [Processor3] Fetched[5] MessageID:urn:uuid:19f02a23-6149-4c82-be32-9ec69986a45e  
 [2013-07-10 12:39:43,995] DEBUG - MSMPLog [Processor3] Fetched[6] MessageID:urn:uuid:ba76517e-f4f2-4a5d-81eb-ed6c4f260783  
 [2013-07-10 12:39:44,006] DEBUG - MSMPLog [Processor3] Fetched[7] MessageID:urn:uuid:3a487564-41ff-464a-bca7-6bc83030f03b  
 [2013-07-10 12:39:44,016] DEBUG - MSMPLog [Processor3] Fetched[8] MessageID:urn:uuid:91fef3e9-1146-4903-a790-02fee3685f26  
 [2013-07-10 12:39:44,031] DEBUG - MSMPLog [Processor3] Fetched[9] MessageID:urn:uuid:cc754b66-11bf-40f0-b9d8-7ec72ac7397a  
 [2013-07-10 12:39:44,045] DEBUG - MSMPLog [Processor3] Fetched[10] MessageID:urn:uuid:06bf808e-f35f-4724-ad34-d723d39b7131  
 [2013-07-10 12:40:38,572] DEBUG - MSMPLog [Processor1] Fetched[9] MessageID:urn:uuid:962808ff-19bf-4d86-a4b1-2e7e0b4363ec  
 [2013-07-10 12:40:38,587] DEBUG - MSMPLog [Processor1] Fetched[10] MessageID:urn:uuid:76ad4a31-91f4-4372-a851-2189723c485c  

 This log is same in the other ESB node as well. But since both of the ESBs servce one backend service the log there will be like this;

 Value is:2  
 Value is:2  
 Value is:2  
 Value is:1  
 Value is:3  
 Value is:2  
 Value is:1  
 Value is:4  
 Value is:3  
 Value is:1  
 Value is:1  
 Value is:3  
 Value is:4  
 Value is:5  
 Value is:3  
 Value is:5  
 Value is:6  
 Value is:4  
 Value is:6  
 Value is:6  
 Value is:5  
 Value is:7  
 Value is:7  
 Value is:7  
 Value is:6  
 Value is:8  
 Value is:1  
 Value is:3  
 Value is:5  
 Value is:6  
 Value is:2  
 Value is:7  
 Value is:7  
 Value is:8  
 Value is:9  
 Value is:8  
 Value is:9  
 Value is:10  
 Value is:2  
 Value is:10  
 Value is:8  
 Value is:9  
 Value is:8  
 Value is:9  
 Value is:3  
 Value is:10  
 Value is:9  
 Value is:10  
 Value is:4  
 Value is:10  
 Value is:5  
 Value is:6  
 Value is:7  
 Value is:8  
 Value is:9  
 Value is:10  
 Value is:1  
 Value is:4  
 Value is:4  
 Value is:5  

JMS MapMessage support in WSO2 ESB 4.7.0

A JMS MapMessage is an object which is used to send a set of name value pairs over the jms transport. Now WSO2 ESB supports the jms mapmessage support in version 4.7.0. Let's go through a simple use case in which jms mapmessage can be used with esb.

First you have to configure ESB with a JMS broker. I have been using Apache ActiveMQ here. But you can use either IBM Websphere MQ, MSMQ or even WSO2 Mesage Broker.First get WSO2 ESB 4.7.0 and Apache ActiveMQ 5.8.0 (or lower version)

 Copy the following jars from AMQ_HOME/lib to ESB_HOME/repository/components/lib

• activemq-broker-5.8.0.jar
• activemq-client-5.8.0.jar
• geronimo-j2ee-management_1.1_spec-1.0.1.jar
• geronimo-jms_1.1_spec-1.1.1.jar

Enable the JMS Transport for ActiveMQ by uncommenting  the transportReceiver for activemq and transportSender for jms configurations found in the ESB_HOME/repository/conf/axis2/axis2.xml

Then you can start the ActiveMQ instance and then the ESB. So that your esb will be connected to ActiveMQ through JMS transport. Then only you can follow up with the mapmessage usage scenario

Now create a proxy service with the following configurations so that ESB will be creating a JMS endpoint and every request made to that proxy will be stored in a JMS queue. 

<?xml version="1.0" encoding="UTF-8"?>
<proxy xmlns="http://ws.apache.org/ns/synapse"
       name="StockQuoteJMSProducerProxy"
       transports="http"
       statistics="disable"
       trace="disable"
       startOnLoad="true">
   <target>
      <inSequence>
         <property name="OUT_ONLY" value="true"/>
         <send>
            <endpoint>
               <address uri="jms:/SimpleStockQuoteService?transport.jms.ConnectionFactoryJNDIName=QueueConnectionFactory&amp;java.naming.factory.initial=org.apache.activemq.jndi.ActiveMQInitialContextFactory&amp;java.naming.provider.url=tcp://localhost:61616"/>
            </endpoint>
         </send>
      </inSequence>
      <outSequence>
         <send/>
      </outSequence>
   </target>
   <publishWSDL uri="file:repository/samples/resources/proxy/sample_proxy_1.wsdl"/>
   <description/>
</proxy>

This proxy service can be used to implement a jms queue and if another proxy is created as a consumer then the message can be send to an actual SimpleStockQuote service endpoint and get a response. 

But here I am changing the SOAP message content to follows so that the content will be saved in a jms queue as a MapMessage. The content is

<soapenv:Envelope xmlns:soapenv="http://www.w3.org/2003/05/soap-envelope">
<soapenv:Body>
<JMSMap xmlns="http://axis.apache.org/axis2/java/transports/jms/map-payload">
    <price>3.4566</price>
    <quantity>15000</quantity>
    <symbol>MSFT</symbol>
</JMSMap>
</soapenv:Body>
</soapenv:Envelope>

Now if you go to the queue named as StockQuoteJMSConsumerProxy you will see the message has been saved but as a MapMessage with name and value pairs.

SSL Tunneling support in WSO2 ESB 4.7.0 with Passthrough HTTP transport

With this configurations HTTPS requests sent by ESB will be tunneled through the http port of the backend proxy.

The backend proxy used here is Squid proxy server.

Steps to install Squid in Ubuntu 12.04:

1. Installation

• sudo apt-get install squid

2. Configuration

• Navigate to /etc/squid3 (u need sudo access)
• Backup the squid.conf 
• Do the following changes to the squid.conf
• Change the port to whichever the port you want

http_port 8888

• Change the host name

visible_hostname localhost

• You can restrict the access of the proxy with a set of hostnames or within a configured time frame using the following properties

acl allowed_network src 10.100.3.0/100
acl allowed_hours time M T W T F 9:00-17:00

http_access allow allowed_network allowed_hours 

3. After the changes you can restart the server

sudo /etc/init.d/squid restart

4. Let's configure the ESB

Backup the axis2.xml in {ESB_HOME}/repository/conf/axis2 directory. Copy the axis2_pt.xml as axis2.xml

Add the following configurations to the transportSender configurations;
1. PassThroughHttpSender, PassThroughHttpSSLSender if you are using passthrough transport or
2. HttpCoreNIOSender and HttpCoreNIOSSLSender if you are using nio transport

<parameter name="http.proxyHost" locked="false">localhost</parameter> //IP of the backend proxy

<parameter name="http.proxyPort" locked="false">8888</parameter> //http port of the backend proxy

<parameter name="HostnameVerifier">AllowAll</parameter>

Deploy SimpleStockQuoteService in the axis2Server in the {ESB_HOME}/samples

Create a proxy in ESB

<proxy xmlns="http://ws.apache.org/ns/synapse" name="StockQuoteProxy" transports="https,http" statistics="disable" trace="disable" startOnLoad="true">
   <target>
      <outSequence>
         <send/>
      </outSequence>
      <endpoint>
         <address uri="http://localhost:9000/services/SimpleStockQuoteService"/>
      </endpoint>
   </target>
   <publishWSDL uri="file:repository/samples/resources/proxy/sample_proxy_1.wsdl"/>
   <description></description>
</proxy>
                                

Now invoke the ESB proxy service with soap-ui

You may watch the logs of the squid server with

sudo tail -f /var/log/squid3/access.log