<definitions xmlns="http://ws.apache.org/ns/synapse">
<sequence name="main" onError="errorHandler">
<in>
<send>
<endpoint>
<loadbalance>
<endpoint>
<address uri="http://localhost:9001/services/LBService1">
<enableAddressing/>
<suspendDurationOnFailure>60</suspendDurationOnFailure>
</address>
</endpoint>
<endpoint>
<address uri="http://localhost:9002/services/LBService1">
<enableAddressing/>
<suspendDurationOnFailure>60</suspendDurationOnFailure>
</address>
</endpoint>
<endpoint>
<address uri="http://localhost:9003/services/LBService1">
<enableAddressing/>
<suspendDurationOnFailure>60</suspendDurationOnFailure>
</address>
</endpoint>
</loadbalance>
</endpoint>
</send>
<drop/>
</in>
<out>
<!-- Send the messages where they have been sent (i.e. implicit To EPR) -->
<send/>
</out>
</sequence>
<sequence name="errorHandler">
<makefault response="true">
<code xmlns:tns="http://www.w3.org/2003/05/soap-envelope" value="tns:Receiver"/>
<reason value="COULDN'T SEND THE MESSAGE TO THE SERVER."/>
</makefault>
<send/>
</sequence>
</definitions>
Executing the Client
Invoke the sample client as follows
ant loadbalancefailover -Di=100
This will send 100 requests to the LoadbalanceFailoverService through Synapse.
Synapse will distribute the load among the three endpoints mentioned in the
configuration in round-robin manner. LoadbalanceFailoverService appends the name
of the server to the response, so that client can determine which server has
processed the message. If you examine the console output of the client, you can
see that requests are processed by three servers as follows:
[java] Request: 1 ==> Response from server: MyServer1
[java] Request: 2 ==> Response from server: MyServer2
[java] Request: 3 ==> Response from server: MyServer3
[java] Request: 4 ==> Response from server: MyServer1
[java] Request: 5 ==> Response from server: MyServer2
[java] Request: 6 ==> Response from server: MyServer3
[java] Request: 7 ==> Response from server: MyServer1
...
Now run the client without the -Di=100 parameter to send requests indefinitely.
While running the client shutdown the server named MyServer1. Then you can observe
that requests are only distributed among MyServer2 and MyServer3. Console output
before and after shutting down MyServer1 is listed below (MyServer1 was shutdown
after request 63):
...
[java] Request: 61 ==> Response from server: MyServer1
[java] Request: 62 ==> Response from server: MyServer2
[java] Request: 63 ==> Response from server: MyServer3
[java] Request: 64 ==> Response from server: MyServer2
[java] Request: 65 ==> Response from server: MyServer3
[java] Request: 66 ==> Response from server: MyServer2
[java] Request: 67 ==> Response from server: MyServer3
...
Now restart MyServer1. You can observe that requests will be again sent to all
three servers within 60 seconds. This is because we have specified
<suspendDurationOnFailure> as 60 seconds in the configuration. Therefore,
load balance endpoint will suspend any failed child endpoint only for 60 seconds
after detecting the failure.
