Events are received by WSO2 CEP/DAS server using event receivers, which manage the event retrieval process. Event receiver configurations are stored in the file system as deployable artifacts. WSO2 CEP/DAS receives events via multiple transports in JSON, XML, Map, Text, and WSO2Event formats, and converts them into streams of canonical WSO2Events to be processed by the server.
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WSO2 CEP/DAS has the capability of receiving events from event receivers via various transport protocols. Following are the event receivers that come with WSO2 CEP/DAS by default. You can write extensions to support other transport.
- Email Event Receiver
- File-tail Event Receiver
- HTTP Event Receiver
- JMS Event Receiver
- Kafka Event Receiver
- MQTT Event Receiver
- SOAP Event Receiver
- WebSocket Event Receiver
- WebSocket Local Event Receiver
- WSO2Event Event Receiver
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In addition to the above, the SQS extension allows you to receive events via SQS. For instructions to download and install an extension, see Downloading and Installing Extensions from the Store. |
Event receiver configuration
An event receiver configuration has four main sections as shown in the example below.
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The above sections of an event receiver configuration are described below.
Section | Description |
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| From | An input event adapter (transport) configuration via which the event receiver receives events. |
| Adapter properties | Specific properties of the selected input event adapter. For information on configuring adapter properties of various transport types, see Event Receiver Types. |
| To | The event stream from which the event receiver will fetch the events for processing. |
| Mapping configuration | The format of the message that is received. You can configure custom mappings on the selected format via advanced settings. For information on configuring custom mappings, see Input Mapping Types. |
Creating event receivers
You can create event receivers either using the management console or using a configuration file as explained below.
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Create an XML file with the following event receiver configurations. An event receiver implementation must start with
<eventReceiveras the root element.>Note In the following configuration, specify the respective adapter properties based on the transport type of the receiver within the
<from>element. For the respective adapter properties of the event receiver configuration based on the transport type, see Event Receiver Types .Code Block language xml <eventReceiver name="EVENT-RECEIVER-NAME" statistics="disable" trace="disable" xmlns="http://wso2.org/carbon/eventreceiver"> <from eventAdapterType="EVENT-ADAPTER-TYPE"> ................................. </from> <mapping customMapping="disable" type="xml"/> <to streamName="Test Stream" version="1.0.0"/> </eventReceiver>The properties of the above configuration are described below.
Adapter property Description nameName of the event receiver statisticsWhether monitoring event statistics is enabled for the receiver traceWhether tracing events is enabled for the receiver xmlnsXML namespace for event receivers eventAdapterTypeType of the event adapter. customMappingWhether a custom mapping is enabled on the receiver. typeType of the enabled custom mapping. streamNameName of the event stream to which the receiver is mapped. Add the XML file to the
<PRODUCT_HOME>/repository/deployment/server/eventreceivers/directory directory. Since hot deployment is supported in the product, you can simply add/remove event receiver configuration files to deploy/undeploy event receivers to/from the server.
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After a receiver is successfully added, it gets added to the list of receivers displayed under under Event in the in the Main menu of the product's management console. Click Edit Edit to change its configuration and redeploy it. This opens an XML-based editor allowing you to edit the event receiverr configurations event receiver configurations from the UI. Do your modifications and click Update. You can also delete it, enable/disable statistics or enable/disable tracing on it using the provided options in the UI as described below.
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