What is the difference between a service task node and a domain specific node (custom work item) in jBPM?
Service task is defined in the bpmn2 specification and custom work items are the natural extension to your own domain requirements. From the implementation point of view the Service task allows you to interact with a Java Bean or a web service directly (just via configuration) and the Custom WorkItem requires you to define a connector (by implementing the WorkItemHandler interface) that you then need to add to the application class path.
Hope this helps.
Regards
Related
I am currently looking into deploying Traefik/Træfik on our service fabric cluster.
Basically I have a setup where I have any number of Applications (services), defined with a tenant name and each of these services is in fact a separate Web UI.
I am trying to figure out if I can configure a single frontend to target a backend so I don't have to define a new frontend each time I deploy a new UI app. Something like
[frontend.tenantui]
rule = "HostRegexp:localhost,{tenantName:[a-z]+}.example.com"
backend = "fabric:/WebApp/{tenantName}"
The idea is to have it such that I can just deploy new UI services without updating the frontend configuration.
I am currently using the Service Fabric provider for my backend services, but I am open to using the file provider or something else if that is required.
Update:
The servicemanifset contains labels, so as to let traefik create backends and frontends.
The labels are defined for one service, lets call it WebUI as an example. Now when I deploy an instance of WebUI it gets a label and traefik understands it.
Then I deploy ANOTHER instance with a DIFFERENT set of parameters, its still the WebUI service and it uses the same manifest, so it gets the same labels, and the same routing. But what I would really want was to let it have a label containing some sort of rule so I could route to the name of the service instance (determine at runtime not design time). Specifically I would like for the runtime part to be part of the domainname (thus the suggestion of a HostRegexp style rule)
I don't think it is possible to use the matched group from the HostRegexp to determine the backend.
A possibility would be to use the Property Manager API to dynamically set the frontend rule for the service instance after creating it. Also, see this for a complete example on using the API.
I'm using Service Fabric v6.1.472. We're trying to switch to using Service Fabric Remoting (https://learn.microsoft.com/en-us/azure/service-fabric/service-fabric-reliable-services-communication-remoting), specifically to use the v2 listeners.
The problem I'm running in to is that the documentation only says how to do it using a single listener via the extension method:
protected override IEnumerable<ServiceInstanceListener> CreateServiceInstanceListeners()
{
return this.CreateServiceRemotingInstanceListeners();
}
This assumes that
The service class implements the remoting interface
There is only one remoting v2 endpoint in the host (I need multiple endpoints).
When digging into the decompiled code, it looks like this extension method uses a hard-coded endpoint name, which would make it impossible to use this for multiple remoting endpoints. Further digging revealed that many of the methods used by the extension method are marked internal.
Short of creating my own library, has anyone else found a workaround to this bit of bad design?
Edit
Microsoft updated their documentation. Under the header "Using explicit V2 classes to use the V2 stack," it is clear how to create listeners without the extension method.
Using 5.1.163 version of service fabric run time.
Created a service fabric application with one stateless web api (i.e. using owin communication listener).
Modified the generated code so that listening endpoint to contain partition id/instance id/new_guid (just as is the case for stateful services). This should allow me to create another app instance so that I can have multi-tenancy at application level.
By default, Local.xml file is set to 1 instance for this service.
Deployed it to local machine by F5. Verified that it is deployed to only one instance.
Verified that service is working fine.
Navigated to local service fabric explorer and clicked on the Cluster/Application/AppType node. Clicked on 'Create app instance'.
It successfully created 2nd app instance.
However in this new instance, the service is deployed to all 5 nodes.
I was expecting it deploy the service instance only one node. Is this a bug? But only in this version of service fabric?
When you deploy a Service Fabric application using Visual Studio (or from PowerShell) you use the Deploy-FabricApplication.ps1 that is generated for your application and found in /scripts under your SF project. This script does two things (mainly):
Create/update the application type
Create a new/upgrade existing instance of the application type
The second part there is similar to what you do in the SF Explorer, except this one also considers the publisher profile file you supply. The PS-script actually reads your publisher profile xml files and extracts any parameters in there to a hashset (a dictionary) and passes that as an argument in step 2.
You can create an instance of an SF application type using the PS cmdlets (alternatively you can use FabricClient). The following command does this: New-ServiceFabricApplication. Here you have the chance to supply your own application parameters, including instance count for services in your new application instance (if you have a dynamic parameter for that in your application manifest).
So, when you use the SF explorer to create a new application instance you cannot control how that instance is created, it is always using the default parameter values as specified directly in ApplicationManifest.xml, not values you have specified in your publisher profiles (local1, local5, cloud, etc.).
To controll the creation, run New-ServiceFabricApplication with yor parameters as a hashset.
Is it possible to execute a service in angular 2 at startup?
bootstrap does not execute the service's contstructor.
And also, the injector is executing the service's contstructor each time there is an injection of the service in some component. is there a way to make the service singelton and make sure the ctor will run only once?
Add the service only to bootstrap and not to proiders in your components.
If you inject it in your AppComponent it will be instantiated and only once.
Adding the service to providers on a component creates a new instance for each component instance.
Bootstrap won't start the service, a consuming class that is injecting the service will. By listing it in bootstrap you will get singleton.
If you follow the convention of listing your injectable services (LogRepository) into the bootstrap, then all services will be singleton. (As in LogRepository)
bootstrap(TheApp, [HTTP_PROVIDERS,LogRepository]);
You can get more instances of injectable services if you list them as providers on a component but starting out, just list them in the bootstrap(). All singleton then.
How to create process with 1 service task - rest which calls
http://www.webservicex.net/currencyconvertor.asmx/ConversionRate?FromCurrency=EUR&ToCurrency=USD
and sets this value as parameter which can be seen later, using jbpm console(kie workbench)? JBOSS docs are mostly for user tasks.
My recommended solution is to create a new WorkItemHandler implementation that calls the web service get the results and inject that as a process variable.
You can see a similar example that calls web services here: https://github.com/droolsjbpm/jbpm-playground/tree/master/customer-relationships-workitems
HTH
There is a REST service task that you can use, available out-of-the-box in the web-based designer (under service tasks, so implemented as a custom service task). The associated handler should also be registered automatically when using the jbpm-installer:
https://github.com/droolsjbpm/jbpm/blob/master/jbpm-installer/conf/META-INF/CustomWorkItemHandlers.conf#L4