It is successful to create the event receiver type kafka in the first time.
however the second , when I run the kafka again and create a new event receiver from wso2 cep .
It show the message as below
"Failed to add event receiver, Exception: java.lang.NoClassDefFoundError: org/apache/kafka/common/security/JaasUtils"
and failed to add the new event receiver.
How should I handle that cases?
If you want to set kafka event receiver you need to configure some prerequisites. You need to add some dependency jar files to set kafka event receiver. you can refer this doc for more details.
Related
Can ZeroMQ Publisher Subscriber sockets be configured so that a newly-connected client always receive last published message (if any)?
What am I trying to do: My message is a kind of system state so that new one deprecates previous one. All clients has to have current states. It works for already connected clients (subscribers) but when the new subscriber appears it has to wait for a new state update that triggers a new message. Can I configure PubSub model to send the state to the client immediately after connection or do I have to use a different model?
There is an example in
the ZMQ guide called Last Value Caching. The idea is to put a proxy in between that caches the last messages for each topic and forwards it to new subscribes. It uses an XPUB instead of a PUB socket to react on new connections.
I am using WSO2 CEP 4.2.0 and have created MQTT input event adapter. I have also created the receiver which will receive the data from a external topic and then using streams, I am adding some logics and then same message will be published using publishers to another external topic.
Now, When I restart the application, I get below two messages:
INFO {org.wso2.carbon.event.input.adapter.core.internal.InputAdapterRuntime} - Connecting receiver mqttreceiver_test
INFO {org.wso2.carbon.event.input.adapter.mqtt.internal.util.MQTTAdapterListener} - MQTT Connection successful
And then When I am publishing the message from external mqtt client, I can see that message arrives the event receiver and after stream processing, the message goes to output event publisher.
But after approx 5 mins, the messages are not received any more in the event receiver. I do not get any error message also in logs but what I could sense is may be the input adapter is not listening any more.
Any suggestions or any guidance will help.
Thanks
Few things I could suggest to debug this issue:
Perhaps the flow is broken so that the event does not reach the
output event publisher? You could use logger event publisher [1] and log
the stream that is generated by the MQTT input event adapter.
Enable debug logs for package
org.wso2.carbon.event.input.adapter.mqtt.internal.util so that you
will see a log when the MQTTAdapterListener receives a message (See
[2] ). You can follow [3] to enable debug logs.
When the issue
happens, take a thread dump and see whether the MQTTAdapterListener
thread is running.
Hope these will help you to narrow down the issue.
[1] https://docs.wso2.com/display/CEP420/Logger+Event+Publisher
[2] https://github.com/wso2/carbon-analytics-common/blob/v5.1.3/components/event-receiver/event-input-adapters/org.wso2.carbon.event.input.adapter.mqtt/src/main/java/org/wso2/carbon/event/input/adapter/mqtt/internal/util/MQTTAdapterListener.java#L150
[3] https://docs.wso2.com/display/CEP420/Logging
I am new to WSO2 CEP
I have created the entire flow to read the JMS message and split it using Text formatter. The problem is that when I try to push messages into the queue, it is not able to reach the the output event adaptor. I have a mysql event adaptor and configured it into my event formatter but I keep getting the below message in my log
[2014-02-13 21:20:06,347] ERROR - {ReceiverGroup} No receiver is reachable at reconnection, can't publish the events
[2014-02-13 21:20:06,352] ERROR - {AsyncDataPublisher} Reconnection failed for for tcp://localhost:7661
Can someone help me understand what is this tcp://localhost:7661 is all about
Regards
Subbu
tcp://localhost:7661 is the default port to which Thrift(WSO2 events are published). It seems a default event formatter has been created and trying to publish events to that port.
Can you check your list of event formatters and ensure that no event formatters of type WSO2Event are created. This event formatter might be automatically created if you set an exported stream to be 'pass-through' when creating the execution plan.
You can enable event tracing[1] and monitor to determine exactly upto which point the event is coming in your configured flow.
[1] http://docs.wso2.org/display/CEP300/CEP+Event+Tracer
HTH,
Lasantha
I am working with wso2cep3.0. I went through the docs of wso2cep but there is no exaplanation about wso2cep how would i use it
1.what is the use of Input Event Adapter:-in my concern for getting the data from client.
2.Event Builder means incoming data format specifier.
3.Event Formatter means Outgoing data format specifier.
4.Output Event Adapter out put handler.
but how can i use this thing means any program or any event writer most important how would i publish this to external world example as http endpoint or https or jms.
I am unable to understand how would i start and where can i start.
Please suggest me i know the ESB,DSS,IS,BPS
For a typical CEP usecase, you configure the input event adaptor to connect to an event source, such as a JMS endpoint, Thrift endpoint(WSO2Event adaptor in CEP 3.0.0) etc. Event builder specifies how the incoming message will be mapped.
Next the execution plans will have the actual query (the processing part) of the execution flow. This is where the CEP engine actually processes the events.
Event formatter formats it to an output format as needed. The output event adaptor connects to the actual endpoint to which the processed result would be published. It would go and publish to a JMS endpoint, email, database etc.
To get started, you need to create an input event adaptor, then an event builder that uses the input event adaptor, then the execution plan, then the output event adaptor, and an event formatter that would format the result from the execution plan and send to the relevant output adaptor. You can find the flow in [1].
You can find example configurations in /samples/artifacts directory. You can find an overview of samples in [2] and can find how to run them [3]. Each sample has an associated producer and a consumer that simulates real world event producers/consumers. Samples would be the best place to learn more about CEP configurations.
[1] http://docs.wso2.org/display/CEP300/CEP+Configuration+Overview
[2] http://docs.wso2.org/display/CEP300/Overview+of+Samples
[3] http://docs.wso2.org/display/CEP300/Setting+up+CEP+Samples
If I have a distributed CEP setup with a JMS broker as the primary input.
Now if we tell our client application to send event to Topic X, the events will be distributed to each node in the CEP cluster, as each one will be listening on same Topic X.
Will this lead to duplication of results (lets say if I am counting certain data field, now since each node is receiving duplicate data, will my count be double of actual value if I have a 2 node cluster)
Can the CEP work off a JMS Queue instead of a Topic ? This way which ever node gets the event data first will consume the message off the Queue ? Does WSO2 CEP support JMS Queues ?
No, currently (CEP 2.0.1) does not have support to receive events from JMS queue.
But if this is your requirement then you can write your own CEP addeptor(broker) to receive events from a queue and push that to CEP.
To create a custom broker
Create an appropriate Broker Type by extending org.wso2.carbon.broker.core.BrokerType and an appropriate Broker Type Factory by extending the org.wso2.carbon.broker.core.BrokerTypeFactory from the jar org.wso2.carbon.broker.core-4.0.5.jar
Then to configure that broker with the CEP create a file called "broker.xml" at wso2cep-2.0.1/repository/conf
and add the following XML:
<brokerTypes xmlns="http://wso2.org/carbon/broker">
<brokerType class="<<class reference>>" /> ...
</brokerTypes>
Find a detail documentation on creating a custom broker at http://suhothayan.blogspot.com/2013/02/writing-custom-broker-for-wso2-cep.html