Quick Start Guide

WSO2 Complex Event Processor monitors the transactions and activities of an enterprise (referred to as events), analyses them and presents the results to a range of interfaces in real time. Not having to store this information enables it to process and present information with greater speed.

The following sections walk you through the basic features of the CEP to get you started.

Creating a simple event flow

An event flow refers to a specific combination of event streams, event receivers, event publishers and execution plans. The following steps describe how to define these elements of an event flow.

Step 1: Add an event stream

Event stream defines the events which goes through a particular flow by defining the event's attributes and it's types. An event stream can be created in the CEP Management Console as follows.

1. Log into the CEP Management Console and click on the Main tab. Under Manage, click Streams to open the Available Event Streams page. 
2. Click Add Event Stream to open the Define New Event Stream page. 

3. Enter information as follows to create a new event stream named org.wso2.event.sensor.stream.
   
   Event Stream Details

   Parameter Name	Value
   Event Stream Name	org.wso2.event.sensor.stream
   Event Stream Version	1.0.0

   Stream Attributes

   Click Add to add the attribute after entering the attribute name and attribute type.

   Attribute Category	Attribute	Attribute Type
   Meta Data	timestamp	long
   	isPowerSaverEnabled	bool
   	sensorId	int
   	sensorName	string
   Correlation Data	longitude	double
   	latitude	double
   Payload Data	humidity	float
   	sensorValue	double

4. Click Add Event Stream to save the information.

Step 2: Add an event receiver

Events received by the CEP server have different formats such as XML, JSON and Map. Event receivers transform these events to WSO2 Events that can be directed to an event stream defined in the CEP.

In this step, you will create an event receiver named httpReceiver which directs events to the event stream named  org.wso2.event.sensor.stream that was created in Step 1. The receiver can be created using the Management Console as follows.

1. Log into the CEP Management Console and click on the Main tab. Under Manage, click Receivers to open the Available Receivers page.
2. Click Add Event Receiver to open the Create a New Event Receiver page.

3. Enter information as follows to create the new event receiver named httpReceiver.
   

   Parameter Name	Value
   Event Receiver Name	httpReceiver
   Input Event Adapter Type	http
   Transports	all
   Event Stream	org.wso2.event.sensor.stream
   Message Format	json

4. Click Add Event Receiver to save the information.

Step 3: Add an Event Publisher

Event publishers publish events processed by the WSO2 servers to external applications. These events are published via HTTP, Kafka, JMS, etc. in  JSON, XML, Map, text, and WSO2Event formats  to various endpoints and data stores.

In this step, you will create an event publisher named loggerPublisher to publish events from the event stream named  org.wso2.event.sensor.stream that was created in Step 1. Since the output event adapter type of this publisher is logger, the events published will be logged in the CEP CLI. The publisher can be created using the Management Console as follows.

1. Log into the CEP Management Console and click on the Main tab. Under Manage, click Publishers to open the Available Publishers page.
2. Click Add Event Publisher to open the Create a New Event Publisher page.

3. Enter information as follows to create the new event publisher named  loggerPublisher.
   
   

   Parameter Name	Description
   Event Publisher Name	loggerPublisher
   Event Source	org.wso2.event.sensor.stream
   Output Event Adapter Type	logger
   Message Format	text

   
   

4. Click Add Event Publisher to save the information.

Step 4: View the simple event flow

This step involves viewing the event flow you created and understanding how the different elements in it are connected. The event flow can be viewed as follows.

1. Log into the CEP Management Console if you are not already logged in. 
2. Click the Main tab and then click Flow to open the CEP Event Flow page. The event flow you created is displayed as follows.
    
   This diagram indicates that httpReceiver forwards events to the org.wso2.event.sensor.stream.1.0.0 stream. These events are then published by the loggerPublisher.

Receive and log events

Step 5: Receive events via HTTP transport

Navigate to <CEP_HOME>/samples/producers/http and run the following command which sends events to the CEP via the HTTP transport.

ant -Durl=http://localhost:9763/endpoints/httpReceiver -Dsn=0001

This builds the HTTP client and sends the events in the <CEP_HOME>/samples/artifacts/0001/httpReceiver.txt file to the httpReceiver endpoint. You can view the details of the events that are sent as shown in the log below. These logs are published by the publisher created in Step 3.

The logs of the JSON events received by the CEP server will be displayed in the CLI as shown in the example below.

Processing events with an execution plan

Step 6: Add another event stream

1. Log into the CEP Management Console and click on the Main tab. Under Manage, click Streams to open the Available Event Streams page. 
2. Click Add Event Stream to open the Define New Event Stream page. 
3. Enter information as follows to create the event stream named org.wso2.event.sensor.filtered.stream.
   

   Event Stream Details

   Paramater Name	Value
   Event Stream Name	org.wso2.event.sensor.filtered.stream
   Event Stream Version	1.0.0

   Stream Attributes
   

   Attribute Category	Attribute	Attribute Type
   Meta Date	timestamp	long
   	sensorName	string
   Correlation Data	longitude	double
   	latitude	double
   Payload Data	sensorValue	double

4. Click Add Event Stream to save the information.

Step 7: Add an execution plan 

An Execution Plan can import one or more streams from the server for processing and push zero or more output streams back to the server. Refer Processing Events for further explanations.

1. Log into the CEP Management Console and click on the Main tab. Under Manage, click Execution Plans to open the Available Execution Plans page. 
2. Click Add Execution Plan to open the Create a New Execution Plan page.

3. Enter information as follows to create the new execution plan
   

   Parameter Name	Value
   Import Stream	org.wso2.event.sensor.stream:1.0.0
   As	sensorStream
   Value Of	filteredStream
   StreamId	org.wso2.event.sensor.filtered.stream:1.0.0

4. Click Import and then click Export. The section for query expressions will be updated as shown below.
   

5. Add the following query expression.

   

   from sensorStream [sensorValue > 100]
   select meta_timestamp, meta_sensorName, correlation_longitude, correlation_latitude, sensorValue
   insert into filteredStream	

   This query includes the value sensorValue > 100. Therefore, when the execution plan forwards events from org.wso2.event.sensor.stream:1.0.0  to org.wso2.event.sensor.filtered.stream:1.0.0, events in which the value for the sensorValue attribute is less than 100 will be dropped.

6. Click Validate  Query Expressions. Once you get a message to confirm that the queries are valid, click Add Execution Plan.

Publish events in dashboard

Step 8: Add a UI event publisher

In this step, you will add another publisher named uiPublisher to publish events from the stream named org.wso2.event.sensor.filtered stream to the Analytics Dashboard.

1. Log into the CEP Management Console and click on the Main tab. Under Manage, click Publishers to open the Available Publishers page.
2. Click Add Event Publisher to open the Create a New Event Publisher page.

3. Enter information as follows to create the new event publisher named UIPublisher.
   

   Parameter Name	Description
   Event Publisher Name	uiPublisher
   Event Source	org.wso2.event.sensor.filtered.stream:1.0.0
   Output Event Adapter Type	ui
   Message Format	wso2event

4. Click Add Event Publisher to save the information.

Step 9: Create a dashboard and a gadget

WSO2 Analytics Dashboard will be used as the tool to analyse the output of the event flow you created in this guide. This step creates a dashboard and a gadget which analyses events from the  org.wso2.event.sensor.filtered.stream stream published by the uiPublisher publisher.

1. Log into the CEP Management Console. In the Main tab, click Analytics Dashboard.
2. Log into the Analytics Dashboard with your username and password.
3. Click CREATE GADGET to open the CREATE A GADGET page.
4. Select  org.wso2.event.sensor.filtered.stream for the Analytics Table/Event Stream parameter. Then click Next.

5. Select Line for the Chart Type parameter. Then enter values as follows in the rest of the parameters relating to the chart.
   
   

   Parameter Name	Value
   Title	Sensor Value VS Timestamp
   X-Axis	TIMESTAMP
   Y-Axis	sensorValue
   Interpolation Method	Monotone

6. Click Add to Gadget Store  to save the gadget in the gadget store. You will return to the DASHBOARDS page.
7. Click CREATE DASHBOARD to open the CREATE A DASHBOARD page.

8. Enter information as follows for the new dashboard and click Next.
   
   

   Parameter Name	Value
   Name of your Dashboard	Sensor Statistics
   Description	This dashboard indicates the sensor value at different times in a particular location.

9. Select the Single Column layout as the layout in the next page. The layout will open.
10. Click the following icon to open the available gadgets.
     
11. Drag and drop the Sensor Value VS Timestamp gadget to a grid in the layout as shown below.
     

Step 10: Send Events to the HTTP Receiver via Curl Command

This step sends events to the receiver named httpReceiver using a curl command. These events are processed by the event flow you created, and published in the CEP CLI by the publisher created in Step 3.

1. Issue the following curl command.

   curl -X POST -d "{ "event": { "metaData": { "timestamp": 1439468145264 , "isPowerSaverEnabled": false, "sensorId": 701, "sensorName": temperature }, "correlationData": { "longitude": 4.504343, "latitude": 20.44345 }, "payloadData": { "humidity": 2.3, "sensorValue": 96.5 } } }" http://localhost:9763/endpoints/httpReceiver --header "Content-Type:application/json"

   The following log will appear in the CEP CLI.
   

   Note that the Sensor Statistics dashboard you created does not get updated. This is because the value for the sensorValue attribute is less than 100 in this event. Therefore, it gets dropped by the filter you created in the execution plan, and as a result, it is not forwarded to the  org.wso2.event.sensor.filtered. stream:1.0.0 stream.

2. Issue another command with a value greater than 100 for the sensorValue attribute as follows.
   

   curl -X POST -d "{ "event": { "metaData": { "timestamp":1439467524120 , "isPowerSaverEnabled": false, "sensorId": 701, "sensorName": temperature }, "correlationData": { "longitude": 4.504343, "latitude": 20.44345 }, "payloadData": { "humidity": 2.3, "sensorValue": 156 } } }" http://localhost:9763/endpoints/httpReceiver --header "Content-Type:application/json"
   
   

    The following log will appear in he CEP CLI.
   
   

   The event is forwarded to the  org.wso2.event.sensor.filtered. stream:1.0.0 stream since the value for the sensorValue attribute is greater than 100. Therefore, the Sensor Statistics dashboard will be updated as shown below.
    

3. Issue more curl commands as follows with several timestamps and sensor values. 

   curl -X POST -d "{ "event": { "metaData": { "timestamp": 1439467524120 , "isPowerSaverEnabled": false, "sensorId": 701, "sensorName": temperature }, "correlationData": { "longitude": 4.504343, "latitude": 20.44345 }, "payloadData": { "humidity": 2.3, "sensorValue": 156 } } }" http://localhost:9763/endpoints/httpReceiver --header "Content-Type:application/json"

   curl -X POST -d "{ "event": { "metaData": { "timestamp": 1439467890957 , "isPowerSaverEnabled": false, "sensorId": 701, "sensorName": temperature }, "correlationData": { "longitude": 4.504343, "latitude": 20.44345 }, "payloadData": { "humidity": 2.3, "sensorValue": 170 } } }" http://localhost:9763/endpoints/httpReceiver --header "Content-Type:application/json"

   curl -X POST -d "{ "event": { "metaData": { "timestamp": 1439467951518 , "isPowerSaverEnabled": false, "sensorId": 701, "sensorName": temperature }, "correlationData": { "longitude": 4.504343, "latitude": 20.44345 }, "payloadData": { "humidity": 2.3, "sensorValue": 131 } } }" http://localhost:9763/endpoints/httpReceiver --header "Content-Type:application/json"

   curl -X POST -d "{ "event": { "metaData": { "timestamp": 1439467992936 , "isPowerSaverEnabled": false, "sensorId": 701, "sensorName": temperature }, "correlationData": { "longitude": 4.504343, "latitude": 20.44345 }, "payloadData": { "humidity": 2.3, "sensorValue": 126 } } }" http://localhost:9763/endpoints/httpReceiver --header "Content-Type:application/json"

   curl -X POST -d "{ "event": { "metaData": { "timestamp": 1439468050928 , "isPowerSaverEnabled": false, "sensorId": 701, "sensorName": temperature }, "correlationData": { "longitude": 4.504343, "latitude": 20.44345 }, "payloadData": { "humidity": 2.3, "sensorValue": 145 } } }" http://localhost:9763/endpoints/httpReceiver --header "Content-Type:application/json"

   Since the value for the sensorValue attribute is greater than 100 in all these events, the dashboard will be updated as shown below. These events will also be logged in the CEP CLI.

   Send sensor events with several timestamps and sensorValues, The dashboard will now get effected with the sent event since sensorValue is over 100 and the event gets sent to the dashboard. These events will get logged in the CEP CLI as well.
   
   

Deploying execution plans using templates

Step 11: Create and deploy a template

The following is the configuration of the execution plan you created in this guide as a template. This configuration should be saved in a XML file in the <CEP_HOME>/repository/conf/cep/domain-template directory.

$filteringVal  can be configured to the expected filtering value from the Execution manager.

<templateDomain name="SensorStatistics">
    <description>Sensor Statistics Analysis</description>
    <templates>
        <template name="Filtering template">
            <description>To filter the sensor events with a given sensor value</description>
            <executionPlan>
                <![CDATA[
                /* Enter a unique ExecutionPlan */
                @Plan:name('ExecutionPlan')
                /* Enter a unique description for ExecutionPlan */
                -- @Plan:description('ExecutionPlan')
                /* define streams/tables and write queries here ... */
                @Import('org.wso2.event.sensor.stream:1.0.0')
                define stream sensorStream (meta_timestamp long, meta_isPowerSaverEnabled bool, 
					meta_sensorId int, meta_sensorName string, correlation_longitude double, correlation_latitude double, 
					humidity float, sensorValue double);
                @Export('org.wso2.event.sensor.filtered.stream:1.0.0')
                define stream filteredStream (meta_timestamp long, meta_sensorName string, correlation_longitude double, 
					correlation_latitude double, sensorValue double);
                from sensorStream [sensorValue > $filteringVal]
                select meta_timestamp, meta_sensorName, correlation_longitude, correlation_latitude, sensorValue
                insert into filteredStream
                 ]]>
            </executionPlan>
            <parameters>
                <parameter name="filteringVal" type="double">
                    <displayName>Filtering Value</displayName>
                    <description>Only the sensor values below filtering value will be dropped</description>
                    <defaultValue>100</defaultValue>
                </parameter>
            </parameters>
        </template>
    </templates>
    <streams>
        <stream>
        {
          "name": "org.wso2.event.sensor.filtered.stream",
          "version": "1.0.0",
          "nickName": "",
          "description": "",
          "metaData": [
            {
              "name": "timestamp",
              "type": "LONG"
            },
            {
              "name": "sensorName",
              "type": "STRING"
            }
          ],
          "correlationData": [
            {
              "name": "longitude",
              "type": "DOUBLE"
            },
            {
              "name": "latitude",
              "type": "DOUBLE"
            }
          ],
          "payloadData": [
            {
              "name": "sensorValue",
              "type": "DOUBLE"
            }
          ]
        }
        </stream>
        <stream>
        {
          "name": "org.wso2.event.sensor.stream",
          "version": "1.0.0",
          "nickName": "",
          "description": "",
          "metaData": [
            {
              "name": "timestamp",
              "type": "LONG"
            },
            {
              "name": "isPowerSaverEnabled",
              "type": "BOOL"
            },
            {
              "name": "sensorId",
              "type": "INT"
            },
            {
              "name": "sensorName",
              "type": "STRING"
            }
          ],
          "correlationData": [
            {
              "name": "longitude",
              "type": "DOUBLE"
            },
            {
              "name": "latitude",
              "type": "DOUBLE"
            }
          ],
          "payloadData": [
            {
              "name": "humidity",
              "type": "FLOAT"
            },
            {
              "name": "sensorValue",
              "type": "DOUBLE"
            }
          ]
        }
        </stream>
    </streams>
</templateDomain>

Step 12: Configure a template

1. If the CEP server was running when you created and deployed the template, restart the CEP server.
2. Log into the CEP Management Console. Click the Main tab and then click Execution Manager. The dashboard home page with the available domains will be displayed as follows.
   
   
3. Click on SensorStatistics to open the Configurations page. Then click Add Configuration.
    

4. Enter information as follows and then click Add Configuration.
   

   Parameter Name	Value
   Configuration Name	FilterSensorValues
   Description	Filter events which
   Filtering Value	125.6

   You will receive a message to confirm that the configurations were successfully saved. Close the message. The configuration added will be displayed in the Configurations page as follows.
   

Step 13: View the elements of the event flow

Log into the CEP Management Console and click the Main tab. Then click Flow   to open the CEP Event Flow page. The complete event flow you created in this guide will be displayed as follows.

The following is a summary of this guide which describes each element in the event flow.