This will convert the events/streams from an Input Adaptor that supports WSO2-Events into an event stream that is compatible with the Event Processor.
WSO2-Event has three data types (Meta, Correlation and Payload), which can be mapped to CEP back-end runtime event attributes by specifying the mapping in the event builder.
Configuring through the Management Console UI
1. Log in to the CEP management console and select the Main menu in the left hand side of the screen. Then select the Add menu item under Event Builder menu.
2. The Create a New Event Builder window opens, using which you can configure new event builders. Enter the following details in the form to create an WSO2-Event based event builder as shown in the screenshot below.
In this UI, there are several properties that need to be filled when creating an event builder. The user interface is divided in to 3 main components (From, Mapping and To) and all properties come under a specific section (except the event builder name) to make it more understandable.
- Event Builder Name - Property that used to uniquely identify a event formatter configuration.
- Input Transport Adaptor - The Input Transport Adaptor which you are going to use to publish the events to the CEP. Only already created Input Transport Adaptors will be listed here. Select the appropriate adaptor by name from the drop down. It is numbered as "1".
- Input Transport Adaptor properties - These properties will be need by the input transport adaptor and will depend on the selected input transport adaptor type. It is numbered as "2". For WSO2Event based input transport adaptors the properties needed are,
- Stream Definition - The stream name of the incoming WSO2Event stream
- Stream Version - The version of the incoming stream
- Input Mapping Type - This property will change based on the transport adaptor selected. Only mapping types supported by a particular transport adaptor will be listed. Select the required mapping type from the list. In the WSO2Event mapping case, it will be 'wso2event'. It is numbered as "3"
- WSO2Event mapping properties - These properties will map the incoming stream to the outgoing stream which will be received by the Event Processor. It is numbered as "4". For WSO2Event mapping, it will be further divided into three subsections as Meta Data, Correlation Data and Payload Data. You need to map an incoming stream attribute to an outgoing stream attribute by providing the necessary details in the relevant input fields. For example, to add a mapping to payload data attribute, go to the row for adding a payload data and
- Enter the attribute name of the incoming stream in Input Attribute Name
- Enter the attribute name for the outgoing stream in Mapped To
- Select the data type of the attribute from the To Stream Data Type drop down
- Click Add to add the individual attribute mapping to the event builder
- To Stream Name - This will be the stream name of the outgoing stream
- To Stream Version - The version of the outgoing stream
3. After adding the relevant details click the Add Event Builder button. The Available Event Builders page will open. To view event builder configurations, click on the event builder name. To delete an event builder, click the Delete button.
Editing Event Builder Configuration through the Management Console
By Clicking the Edit button of the relevant event builder, you will able to edit the event builder configuration and redeploy it. When you click the Edit button, it will redirect to an XML based editor window which will allow you to edit the event builder configuration from UI without opening the configuration file in the file system.
Click Update after editing the configuration to save the changes and redeploy.
Configuring through an XML File
You can specify a event builder configuration through an xml file and deploy it in the deployment directory of the server. Event Formatter deployment directory is available at <CARBON_HOME>/repository/deployment/server/eventbuilders . This is a hot deployment directory, where the event builder will be automatically undeployed and deployed when you save the changes to the file system.
1. Create an XML file and enter the following WSO2Event based event builder configurations inside the above mentioned hot deployment directory. Event builder implementation needs to start with "eventbuilder" root element and its default namespace should be set to http://wso2.org/carbon/eventbuilder as in the example below.
<?xml version="1.0" encoding="UTF-8"?>
<eventBuilder name="SearchStatBuilder" xmlns="http://wso2.org/carbon/eventbuilder">
<from transportAdaptorName="localEventReceiver" transportAdaptorType="wso2event">
<from dataType="meta" name="ipAdd"/>
<to name="ipAddress" type="string"/>
<from dataType="payload" name="username"/>
<to name="username" type="string"/>
<from dataType="payload" name="keywords"/>
<to name="searchTerms" type="string"/>
<to streamName="searchStatistics" version="1.0.0"/>