I'm using elsa-workflow v1.5 and trying to resume a workflow when user commit an action, by fetching the related workflow instance from db using this method
await _workflowInstanceStore.ListAllAsync()
But got an error about the data reader being open
Now I'm wondering if it is a valid approach? and if it is, how can I resolve this error?
To answer your question, the code you are using is valid. What you are experiencing is caused by the way Elsa 1.5 manages the DB context.
Unless you are willing to fork Elsa 1.5 and reimplement the persistence EF Core provider or provide your own implementation of the persistence abstractions, I'm afraid there's no simple way to resolve this error other than upgrading to Elsa 2.0 where this is fixed.
Related
I created a .net 6 minimal API project with EF Core that uses DI to create repositories with Scoped lifetime. The API project uses mediatr to send the request to a proper handler. The handler's get injected with db repositories. This works when I run this project directly.
I am migrating that project to an AWS Lambda project using the new AWS .NET 6 Templates in the visual studio toolkit. For whatever reason, the exact same code that runs fine in the minimal API project now throws an error because the injected repositories dispose their connections before the end of the request.
This error occurs anytime I run a command against the database.
I believe this is happening because of a serialization error that occurs in entity framework core. This issue doesn't occur in my regular project because I'm guessing it's using a different serializer to handle the serialization of entities.
The errors being thrown are:
System.Text.Json.JsonException: A possible object cycle was detected. This can either be due to a cycle or if the object depth is larger than the maximum allowed depth of 32. Consider using ReferenceHandler.Preserve on JsonSerializerOptions to support cycles.
Cannot access a disposed context instance
If I update the Json Serializer that .net is using to handle cycles, then the 1st error turns into: "System.NotSupportedException: Serialization and deserialization of 'System.Type' instances are not supported".
This looks like some sort of conflict with Pomelo Entity Framework Core
and the way the .net 6 lambda templated project is setup.
EDIT:
After looking at this more, I think the issue is with whatever serialization library that AWS Lambda template project uses vs whatever serialization library is normally used by Pomelo to handle things.
Can we update only specific field in mongodb of a spring-boot app using spring-data feature?
Currently, spring-data provides a save method to update as well as save in a document. If two sets of concurrent updates happen in a single document for the different field, we can lose information. I know we can solve the problem using Mongotemplate. Can we solve these problems using spring-data?
Thanks
What about Optimistic Locking feature?
The #Version annotation provides syntax similar to that of JPA in the context of MongoDB and makes sure updates are only applied to documents with a matching version. Therefore, the actual value of the version property is added to the update query in such a way that the update does not have any effect if another operation altered the document in the meantime. In that case, an OptimisticLockingFailureException is thrown.
See Spring Documentation: https://docs.spring.io/spring-data/mongodb/docs/2.0.9.RELEASE/reference/html/#mongo-template.optimistic-locking
With MongoDB 4.0, ACID transactions have arrived in the Document store, enforcing all-or-nothing execution and maintaining data integrity. So, let’s get straight to it by looking at both the synchronous and the reactive execution models.
you could write code like this:
#Transactional
void insertDocuments() {
operations.insert(documentOne);
operations.insert(documentTwo);
}
Complete Spring's documentation:
https://spring.io/blog/2018/06/28/hands-on-mongodb-4-0-transactions-with-spring-data
I read about the server extensions available in neo4j in server mode. I was wondering if it is possible to somehow annotate repository method to use this extension insted of allowing to create query based on method name or #Query annotation?
If not, is there easy way to invoke REST interface methods using Neo4jTemplate?
That's not possible right now, it would be cool though, feel free to raise a JIRA issue that describes your suggestion in more detail. Perhaps Spring-Data-REST Clients allow such a thing.
I'm trying to develop an application using JSF, primefaces, Tomcat7.
When I execute an ajax event, I get this warning:
17-ott-2012 9.26.04 org.apache.myfaces.trinidadinternal.context.PartialViewContextImpl getPartialResponseWriter
AVVERTENZA: getPartialResponseWriter() called during render_reponse. The returned writer is not integrated with PPRResponseWriter
What does it means? What do I have to do to integrate it?
In my server log, on startup, I find some messages about some web context parameters not found. May it be related to the previous warning?
Thanks for your help!!
This class is specific to MyFaces Trinidad. Apparently you're mixing Trinidad with PrimeFaces and it's not working very well. Since you didn't mention anything about Trinidad in your question, it's perhaps a leftover of previous experiments to play around with several component libraries. You might want to remove it before using PrimeFaces.
Can someone point me to example implementation for custom session state management ?
I am looking for following approach "keep all the session state in database and keep only the keys in HttpSession object. "
Can it be done using Spring ?
TIA
-Vin
Using a plain old java proxy for this (or cglib proxies) should be possible, you still need to handle saving/loading to/from your db. There's also the issue to see if a proxied object has been modified this would have to been handled additionally. Spring does not anything to this AFAIK.
Not sure what you're trying to achieve really, but perhaps also memcached-session-manager is interesting for you (shameless plug :-)).