Using functions in Routing Rules in ESB

Many of the times we get puzzled why the expression looks good but it won’t work in ESB expression. Also some of the functions are not available with expression builder at all. But the fact is that all these functions are available with ESB runtime engine and we should be able to use them in expressions. So for the functions which are visible through expression builder, we don’t need step 1 but for functions like dvm-lookup etc. which are not visible via expression builder we have to build that expressions.

So suppose we want to use dvm-lookup to do routing then we would need to perform following steps:

• Create XPath Syntax

• Copy expression from “Source” view

• Paste expression in expression builder

• Append the namespace using text editor. You can get namespace from same XSL file from where you copied XPATH expression.

Once you deploy you should be able to use lookup-dvm (or any other function) within routing rule.

In summary, XPath functions work within ESB routing rule, how you build that expression is totally upto you. As long as you put that xpath function with right namespace you should see results.

NOTE: Using DVM Lookup will affect portability of your code from OESB to OSB (a.ka. ALSB).

Prevent ESB from deleting BPEL process upon un-deployment

Sometimes when you redeploy a BPEL process, because of failed deployment or some other glitches BPEL process is not deployed. Now any ESB services pointing to this BPEL process will delete this entry of BPEL process. That means Routing Service will delete routing rules etc.

In a nutshell, if you do not want to delete the process from ESB on undeployment from BPEL, we need to update esb_config.ini file located in <SOA_HOME>/integration/esb/config folder.

bpelSvcAutoDeletion=false

Default value of this property is true (and is not included in esb_config.ini). We are using this to override default behavior.

Once you make this change restart the server and you should be now good to go.

Resetting ESB Metadata repository

Sometimes ESB repository does not behaves as expected especially after a rigorous DEV cycles or for some other reasons. In order to bring it back to clean, at $ORACLE_HOME/integration/esb/bin directory a script called ‘reset.bat/sh’ is available. This script will cleanup the ESB repository. Simply execute the command as shown below and follow the output.

./reset.sh -DDB_URL=jdbc:oracle:thin:@//db_host:db_port/sid -DDB_USER=oraesb -DDB_PASSWORD=oraesb123

Once you are able to execute it successfully, its very important to restart your ESB instance before using it.

Set Adapter end point properties in ESB

Most of the time we found documentation referring to BPEL when it comes to set end point properties for adapters. BPEL and ESB share the same and they both can configured with same end point properties. Only thing we need to do is to open respective adapter’s .esbsvc file in notepad and add <endpointProperties> element as shown below.

    </invocation>
    <endpointProperties> 
        <property name="minimumDelayBetweenMessages">6000</property> 
    </endpointProperties>
</service>

Generally you can set endpoint properties “RetryCount” and “RetryInterval” apart from that if you have to add any other property you have to follow the route mentioned above.

I would suggest this trick, simply add any property which is available via UI and then open the file in notepad. This way JDeveloper already created that section and what all I have to do is to edit it with the right property name.

Get an Instance ID for Oracle ESB

A new XPath function ehdr:getInstanceID() was added in 10.1.3.3 to get ESB instance IDs. Please remember there is a separate XPath function ora:getInstanceID() which allows you to get BPEL Instance IDs.

Steps to get this are pretty simple:

Simply add function “ehdr:getInstanceID()” as XPath expression and connect it to target field. XSL Source pasted below.

and then, add following end point property in your Routing Service.

enableAccessBusinessEvent=true

After this exercise you should be able to capture ESB instance Id which can be a pretty good tool to track/correlate BPEL/ESB.