There is a requirement in my project where I have class in which I am creating ros2 node (using rclpy) I have to create a publisher and subscriber which subscribe to specific topic ,but I have to publish msg to the topic based on the recieved msg in the callback.
I need to use th above object in other part of the project.
As rclpy.spin() will block the process I tried to run it in a thread ,but I am getting "generator already executing" runtime exception.
Can you please tell me how to resolve this issue or what is the alternate solution for my usecase
Related
I am working on Spring Kafka implementation and my use case is consume messages from Kafka topic as batch (using batch listener). when I consumer the list of messages, will iterate and call the REST endpoint for message enrichment. In case REST API fails for any runtime exception, I have implemented retry logic using spring retry. I want to stop the container, after the number of retries fails. So planning to use KafkaContainerStoppingErrorHandler to achieve this. Does the KafkaContainerStoppingErrorHandler commits the previous success messages - say if we receive 10 messages, and for message 1,2,3,4, enrichment call is success and for message 5 enrichment API call fails. so when we restart the container, will I get all 10 again or will I receive messages 5- 10?
or is there a way we can achieve above use case? I looked into all types of error handles of Spring kafka and need input on how to achieve above requirement.
You will get them all again.
You can use the DefaultErrorHandler (with a custom recoverer) and throw a BatchListenerFailedException to indicate which record in the batch failed.
The error handler will commit the offsets up to that record and call the recoverer with the failed record; in your custom recoverer you can stop the container (use the same logic as the container stopping error handler).
In versions before 2.8, this same functionality is provided by the RecoveringBatchErrorHandler.
I am trying to execute a simple Wordcount stream application but I face the error "Could not create internal topics - Stream-thread exception"
I have seen a similar thread but that seems to be more of a network issue.
Here is no security enabled on the kafka broker.
Only one broker is configured and still this issue.
Can someone let me know how to fix this?
Clean your temporary kafka queues.
Run --list command on kafka to see all the queues starting with your names and ending with -changelog & -repartition and manually run delete on them.
This one worked for me.
Also, check your settings on delete.topic.enable for actual deletion happening. It was not the default setting until 1.0.0 - see https://issues.apache.org/jira/browse/KAFKA-5384
i have connected to kafka using kafka tool and delete them manually
Ok all I am doing is trying to get to my 1st page. And I receive the following exception:
org.springframework.webflow.execution.repository.snapshot.SnapshotNotFoundException:
No flow execution snapshot could be found with id '1'; perhaps the snapshot has been removed?
I am using the following:
Spring Webflow 2.3 (with persistence-context flag)
Spring Security
Spring MVC
Spring-data
JPA 2.0, with/via custom JpaFlowExecutionListener
The only custom part of my JpaFlowExecutionListener is the part where I detach the EntityManager from the scope so it can serialize the flow - I have this as a database backed flow peristence setup. The flows are saved/read from/to the db ok. But I can't get it to render the first view.
From what I can tell here are the steps it goes thru prior to crashing below:
FlowExecutorImpl code calls launchExecution().
PersistentConversation is created.
PersistentConversation thread locked
PersistentConversation put into executionRepository and in PersistentConversationHolder's ThreadLocal Map of conversations. (keeps active thread's list of Conversations)
unlocks - causes a delete of the PersistentConversation in ThreadLocal Map
Then calls FlowExecutorImpl createPausedResult(flowExecution)
Which eventually calls FlowExecutorImpl resumeExecution().
Looks up PersistentConversation in PersistenceConversationHolder map using FlowID, but no longer finds PersistentConversation here.
Retrieves from the database and stuffs db object into a new PersistentConversation.
Attempts to resume Conversation from it's snapshot list but it was deleted in step 5.
For the PersistenceConversationHolder please reference example in this book here.
Any help would be so appreciated!
In case someone also misses this as I did...
At step #5 above when the Thread is unlocked, you need to update the save/update the PersistentConversation to the db, this copy will contain all the snapshot info.
Once I wrote this it was easy to see that there was a missing step.
I am trying to make a multi threaded Qt Application that uses QGLWidgets and I keep getting this error.(I am trying to paint from another thread using QPainter)
And it also looks like I have a huge memory leak because of it.
The error is "QGLContext::makeCurrent() : wglMakeCurrent failed: The operation completed successfully"
I believe this is related to a rather old issue from the Qt mailing list as described here. In short, if the thread calling makeCurrent() does not equal the thread where the device context was retrieved, GetDC() is called. As outlined in the linked thread, the problem is that ReleaseDC() is not called accordingly, resulting in a handle leak, and triggering Windows to return NULL in the call to GetDC() at some point, which makes wglMakeCurrent() fail. I don't know, however, why GetLastError() claims "The operation completed successfully" in this case.
I have many servlets in a web applicaton; for some stange reason, only and only one of them always fails in initialization with the following error trace:-
00000045 ServletWrappe E SRVE0100E: Did not realize init() exception thrown by servlet MyServletX: java.lang.NullPointerException
at com.ibm.ws.webcontainer.WebAppPmiListener.onServletStartInit(WebAppPmiListener.java:120)
at com.ibm.ws.webcontainer.webapp.FireOnServletStartInit.fireEvent(WebAppEventSource.java:237)
at com.ibm.ws.webcontainer.util.EventListeners.fireEvent(EventListeners.java:48)
at com.ibm.ws.webcontainer.webapp.WebAppEventSource.onServletStartInit(WebAppEventSource.java:105)
at com.ibm.ws.webcontainer.servlet.ServletWrapper.init(ServletWrapper.java:261)
at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:444)
at com.ibm.ws.webcontainer.webapp.WebApp.handleRequest(WebApp.java:2841)
at com.ibm.ws.webcontainer.webapp.WebGroup.handleRequest(WebGroup.java:220)
at com.ibm.ws.webcontainer.VirtualHost.handleRequest(VirtualHost.java:204)
at com.ibm.ws.webcontainer.WebContainer.handleRequest(WebContainer.java:1681)
at com.ibm.ws.webcontainer.channel.WCChannelLink.ready(WCChannelLink.java:77)
at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleDiscrimination(HttpInboundLink.java:421)
at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleNewInformation(HttpInboundLink.java:367)
at com.ibm.ws.http.channel.inbound.impl.HttpICLReadCallback.complete(HttpICLReadCallback.java:94)
at com.ibm.ws.tcp.channel.impl.WorkQueueManager.requestComplete(WorkQueueManager.java:548)
at com.ibm.ws.tcp.channel.impl.WorkQueueManager.attemptIO(WorkQueueManager.java:601)
at com.ibm.ws.tcp.channel.impl.WorkQueueManager.workerRun(WorkQueueManager.java:934)
at com.ibm.ws.tcp.channel.impl.WorkQueueManager$Worker.run(WorkQueueManager.java:1021)
at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1332)
I could not figure out if there is anything extra ordinary with this servlet. There is no init() method in this servlet and it extends HTTPServlet. Any idea what could be reason? I am using websphere server 6.0.x. How to get more debugging information in this case?
Well I don't know still cause of above error, but this is how it started working strangely:- i) Re-applied recommended fixes by IBM for my WAS version (especially there are IBM JDK upgrade related fix patches) ii) created a new profile of server iii) Install web application to new profile and it started working.
I don't think this is a product issue.
To debug this problem what i would suggest is to place a simple servlet (kind of Hello World) and deploy it to the server and see what happens.
initialization does not necessarily mean init() method alone.
If you have a static block in your servlet, if you have any variables that are initialized they would all be part of the initialization activity.
Look at the FFDC logs that were generated when this error occurred and that should provide you with clues.
As bkail mentioned, also ensure that yo have the latest fixpacks just to eliminate known problems with the product.
if the hello world servlet works, suggest you place hte servlet code here along with the SystemOut and System Err logs that correspond to this issue along with the relevant FFDC logs and i am sure most of us will be able to help you out with this
HTH
Manglu