Use BPEL callback to asynchronously get result from ODI

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Tutorial – How to use ODI callback web services in conjunction with Oracle Asynchronous BPEL

ODI 11.1.1.5.0 introduced the callback web service paradigm to ODI inbound web services. The concept is similar to the asynchronous pattern in JAX-WS. One difference here is that there is an explicit port type for receiving the callback, once the original web service invocation has completed processing. Also no connections are kept open or alive once the original invocation has been done. Let us go through the whole process of creating a SOA Application and SOA Project that calls out to ODI web service to invoke an ODI Scenario and then receive a response once the Scenario run is complete.

Prerequisites:

• There must already be set up a Weblogic domain with SOA managed server
• You will also need either a Standalone ODI Agent or an ODI managed server under a Weblogic domain.
• You will need an installation of JDeveloper with SOA extension.
• The SOA managed server must be set up as a deployment target in JDeveloper
• Oracle Enterprise Manager must be set up on the Weblogic Admin server for the SOA managed server.

Let us start off with creating an application. I am choosing a SOA Application. You can also choose a Generic Application and configure the Project with requisite technologies.

Choose OK to go to the next page of the wizard. Here you will configure the application name, the directory in which the application files will be stored, as well as the package prefix for the application files. Choose some descriptive names.

Choose Next to continue. Here you can choose the technologies. SOA will already be selected. Add Web Services, XML.

Choose Next. Accept the defaults here unless you really want to configure specific values for the project.

Choose Next.

Here I have chosen to have an empty composite. It is easier this way for maximum flexibility. Once you click Finish, the application is created and the composite is opened.

Open the Component Palette, scroll down click and drag Web Services onto the 'External References' swimlane. A dialog will open up.

The dialog is quite self-explanatory. It is here that we need to set up reference to ODI's inbound web services. For this you need to know the URL to your ODI inbound web service. If this is your default agent deployment using the static Weblogic deployment template provided along with ODI install, the URL will be http(s)://:/oraclediagent/OdiInvoke?WSDL where and are the ones for your ODI managed server.

If you are using ODI Standalone agent, this will be of same format.

If you have created the ODI agent using a dynamic template that you created or you have customized the web application's name, you will have to find out the exact string in place of 'oraclediagent'. You can use Weblogic administration console or Oracle Enterprise Manager to help you find the exact WSDL URL.

In my case ODI is deployed using the static template with default web application name. So pointing to http://localhost:8001/oraclediagent/OdiInvoke?WSDL

See the result above. The Port Type has been set to 'requestPortType' and Callback Port Type has been set to 'requestPortTypeCallback'. This is in keeping with Oracle Asynchronous Web Service pattern. Additionally I have chosen to copy the WSDL and associated artifacts to the project so that the schema types defined in the WSDL will be readily available. Since we are targeting a static WSDL, this choice is fine.

Once you click OK a new page will be shown asking to 'Localize Files' This is to let you store the WSDL file local to the project. Choose OK here also.

See the result below. ODI web service shows up in the External References swimlane. It is time to add a BPEL process now.

From the Component Palette drag-drop BPEL Process (or you can right-click in the center swimlane and choose Insert → BPEL Process). The following dialog opens up.

Note the default choices for BPEL 1.1 and asynchronous BPEL process. Do not change the asynchronous choice to synchronous. You are going to invoke an asynchronous web service. The calls can only be from asynchronous → asynchronous.

You can change the name for the BPEL process. Make sure that 'Expose as a SOAP service' is checked so that you can easily test this BPEL.

Also since this is a simple BPEL process, the input type is being set to ODI web services input type for the operation to start a Scenario and the output to the operation's output type.

Click on the search icon to the right of the 'Input' field and navigate to OdiStartScenWithCallbackRequest type. See the image below.

In the same way navigate to OdiStartScenResponse for the output type. Note that the input type has an additional “..WithCallback...” component in the name. This is not an error.

See the final result below.

This is how the composite will look now.

Now we need to connect the BPEL with the configured ODICallbackSvc external reference to ODI inbound web service. For this bring the mouse over the 'InvokeODIWithCallback' BPEL representation in the center swimlane. Two circles with arrows inside them will show up on the lower left and lower right corners of the box. Drag from here to the green double empty arrows on ODICallbackSvc in the External References swimlane.

See the result in the following image.

So far we have been operating on the composite. Now it is time to work on the BPEL itself. Double-click on the 'InvokeODIWithCallback' box in the center swimlane. The BPEL editor will open up.

The following is what you will see. As you can see the ODI inbound web service again shows up, this time as a Partner Link. Now we need to set up BPEL process to send message to the web service and then receive asynchronous callback from the web service.

Drag-drop an Assign activity and Invoke activity, in that order, immediately after the 'receiveInput' activity. The Assign activity is for us to take the input and pass it on. Invoke activity will invoke the web service with this assigned value.

Mouse-over the Invoke activity and drag-drop from one of the arrows to OdiCallbackSvc on the right. A dialog to configure the Invoke activity opens.

Here you can choose the operation to be invoked as well as the input and output variables. Choose 'InvokeStartScenWithCallback' as the operation to be invoked. You will see that only the Input is active. Output is grayed out. This is because the output is going to to come via the callback. The response to the invocation is just an 'OK' message. It is a oneway SOAP operation.

Now we need to set up the input. For this click on the '+' sign on the right of the 'Input' field. A dialog with an automatically created variable name and the variable type required by ODI inbound web service invocation will pop up.

Choose OK both to this dialog as well as the Edit Invoke dialog.

Now we need to use the Assign activity to pass on the input to the BPEL process to this variable. For this double-click the Assign activity. In the resulting dialog expand the input to BPEL on the left pane and the variable created above on the right pane and do mapping.

Choose OK.

Now let us create a Java activity.

For this expand 'Oracle Constructs' in the Component Palette and drag-drop Java Embedding activity immediately after the Invoke activity.

Double-click the Java Embedding activity and enter the following code. This will create file whose timestamp we can verify.

java.io.File tempFile = new java.io.File(System.getProperty("java.io.tmpdir") + java.io.File.separatorChar + "time.txt"));

try {

if(tempFile.exists())

tempFile.delete();

else

tempFile.createNewFile();

} catch (java.io.IOException ioe {}

Now again expand 'BPEL Constructs' in the Component Palette and drag-drop A Receive activity followed by an Assign activity right after the Java Embedding activity.

The following image shows how the BPEL process looks now.

Now drag from the arrow on the Receive activity to OdiCallbackSvc. The following dialog is shown. Note that there are only two operations to choose from. ODI inbound web service has callback only for starting a Scenario and restarting a Session. Operations involving Loadplan are always asynchronous, so they do not have callbacks. Client has to poll for the status.

Note that there is only one 'Variable' field and no Input/Output. The Receive activity only only receives data so there is no other field. As with the Invoke activity click the '+' sign to the right of the field and accept the result.

Now we need to assign this received data to the output of the BPEL process. For this double-click the Assign activity after the Receive activity, expand the variable that was created above on the left-hand pane and the outputVariable on the right-hand pane and do mapping.

Choose OK and Save All.

In the Application Navigator right-click the Project and choose to deploy it.

Choose to deploy to an Application Server. This is the SOA managed server that user must already have set up.

Choose Next.

I have chosen to overwrite existing composites with same revision ID. Choose Next.

'SOA-ODI' is the SOA managed server that I have configured. Choose Next.

Now click 'Finish'. It will build and deploy the Project to the SOA server.

Open a web browser and enter the URL for Enterprise Manager on the Weblogic Admin server. Navigate to SOA → soa-infra → ODICallback2SOA. Then from the top SOA Composite menu, choose Test Service → the SOAP service endpoint for the BPEL process.

Be sure to choose the correct endpoint. By default it gets set to OdiInvokeCallback. You do not want this.

Rather choose the BPEL SOAP end point. Enter the required values for ODI Scenario invocation. My Scenario issues a 'beep' and then 'sleeps' for 10 secs.

Click 'Test Web Service' button.

Do not be scared. There was no response because the BPEL process is itself an asynchronous process. Click the Launch Flow Trace button. You will see the following:

For clarity I have removed the sandwiched Java_Embedding1 activity information. If you go to your 'temp' directory and look at the timestamp of 'time.txt' file you will find its timestamp to be same as the ending time for the Invoke1 activity.

Congratulations! You have created a BPEL process that will start off an ODI Session, go on and do some other things while letting the ODI Session run and at the end of the Session, ODI will call the BPEL process back with the Session ID.

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