I am writting a manager program in a rcp way with eclipse, so I want to create a "command center" job which will run until the game is over. It'll get input from views, editors or via socket channel which is another job to get remote servers'/clients' request, and vice versa. But I do not know how to do it? So as a summary I have two problem:
How a job communicate with a ui part of eclipse?
How a job communicate with another?
I do not think, that an Eclipse Job is well-suited for this purpose, because jobs are basically used as elementary, but long tasks.
I would create something you do require as a controller/"command center" view, that can be used by the user to control the game. In this case, the view can communicate with the internal model e.g. using the Data Binding API, and with other views using the Selection service.
Or if you would like to control your application automatically in the background, you could create different event listeners, that can create small jobs, that read/write the data model of the application.
Related
I have an event-sourced CQRS architecture hosted in kubernetes. I have a single writer (the "denormalizer service") that listens to events and writes the denormalized views to a datastore. These views are then served by a separate view service. When the denormalizer image is updated through a deployment with new projections it replays all events from the beginning and writes the new views to a different datastore.
So I need 2 instances of denormalizer, one with the old code, and another replaying the events through the new code. When the new code is finished replaying I need to:
1) signal to the view service to switch to the newly written datastore and then,
2) bring down the old denormalizer deployment as it is no longer required.
Problem is, (to my limited knowledge) kubernetes seems ill-equipped to deal with this scenario.
Any idea how I would do something like this?
I don't know the specifics of your system, but two solutions come to my mind.
Using readinessProbe
You can define a readinessProbe for your writer service. Make it report the service is ready, when the rewrite is done. Then, the rolling updater will know when to shut down the old version of the writer and start serving traffic to the new one. The only thing you'd need to do more is notify the viewer to switch to new data source. This could be done by the writer calling some API on the viewer service.
Using separate process
You can create a special process that will execute the procedure you described using Kubernetes API. It is more work than the first solution, but gives you more control over the whole process. It would observe your repository if there are new versions of writers, if yes, it would start a new service, wait for it to be ready, kill the old writer and notify the viewer.
Is there a way for me to programmatically get notified when Bluemix auto scaling has scaled up or down?
I'm reading streaming data from a queue and would like to make sure the number of instances that I have are balanced and data is partitioned correctly
At present this kind of notification service is not available, only you can do is query the instance scaling history in Web UI. I think this requirement is interesting and should be considered to provide to developer in the future.
This kind of alert isn't available yet but you can write a simple script monitoring output of
cf app (appname)
It returns the number of instances running and the state of each one, with the right combination of awk and grep (or a perl script for example) you could have your own alerter while waiting for this of functionality
Exploring (Ado)JobStore (data base job store in general) I met subjects like clustering, load balancing and sharing jobs' work data state across multiple applications.
But I think I didn't find a JobStore subject that covers my scenario.
I need to run Quartz Jobs in Windows Service and I need to be able to change configuration of Triggers in other application (in Admin panel in web application) and the Triggers to be applied by the Quartz in my Windows Service automatically (Quartz tracks changes and applies them).
Is it possible to do this by using AdoJobStore/Clustering mechanism? I mean in terms of JobStore's features, so by using Quartz scheduler API. Not by using SQL and changing data in Quartz tables directly or any other workarounds (according to Quartz's Best Practices doc).
The Quartz.NET scheduler can be accessed remotely, independently of job stores. Since you already have a web app you can add a reference to the remote scheduler and use the API to administer jobs, triggers etc.
I'm designing a MVVM application that does not use WPF or Silverlight. It will simply present web pages in HTML5, styled with CSS3.
The domain is a perfect case for using WF because it involves a number of activities in a long-running process. Specifically, I am tracking the progress of interactions with a customer over a 30 day period and that involves filling out various forms at points along the way, getting approvals from a supervisor at certain times, and making certain that the designated order of activities is followed and is executed correctly.
Each activity will normally be represented by a form on a view designed to capture the desired information at that step. Stated differently, the view that a user sees will be determined by where she is in the workflow at that moment.
My research so far has turned up examples where the workflow is used to execute business logic in accordance with the flowchart that defines it.
In my situation, I need for a user to login then pick up where she left off in the workflow (for example, some new external event has occurred and she needs to fill out the form for that or move forward in the workflow to that step.)
And I need to support the case where the supervisor logs in and can basically be presented with activities that need approval at that time.
So... it seems to me that a WF solution might be appropriate, but maybe the way I want to use it is inverted - like the cart pulling the horse so to speak.
I'd appreciate any insight that anyone here can offer.
Thanks - Steve
I have designed an app similar to yours, actually based on WPF, but the screens shown by the application are actually driven by workflows.
I use a task-based approach. I have some custom activities that create user tasks on a DB. There are different type of tasks, one for every different form type that the application supports. When the workflow reaches one of these special activities, the task is saved to DB and the WF goes idle (bookmark).
Once the user submits the form, the wf is resumed up to the point where another user task is reached and so on.
Tasks can be assigned to different users along the way (final user, supervisor, ..) and they have a pending tasks list where they can resume previous wf instances, etc.
Then, to generate user views (HTML5 forms in your case) you have to read the pending task and translate that into the corresponding form.
Hope you find it useful
In the last days I spent a lot of time creating the architecture for my program, but still have a problem with it. At the moment it looks like this:
DataLayer: Here my context class which derived from DbContext and the mapper classes which derived from EntityTypeConfiguration like JobMap for the Domain objects reside
DomainLayer: Here my domain/business objects like Job or Schedule reside.
Presentation Layer: Here I have the *ViewModel and *View classes (I use WPF for the views)
Now to my question: I want to build a scheduling application with some optimization abilities (it is a single user and single pc application so no further decoupling like web application is needed). But I have the problem that I don't know where this application fits into this architecture?
Considering the following use case: The user clicks a button "Start" on the View which calls the ViewModel which redirects to my scheduling/optimization application. This app then gets all the new jobs from the database and creates/updates the current schedule. The ViewModel should then update the old schedule with the new created one. Finally the View shows the generated schedule to the user.
In this case my ViewModel knows about my application (because it calls it) and about my domain/business objects (because my app will deliver e.g. a Schedule domain object, which the ViewModel encapsulates).
Is this a correct usage of the EF, MVVM and my application?
Regards
To start, you'll want to identify which pieces of your application go where, and that's fairly easy to do. Essentially, you have to ask yourself: Does this method or class help define my domain. If the answer is yes, you put it in the domain layer, and if not, you'll put it in presentation.
Here's how you'd look at it in your example:
Your Presentation layer (PL) receives a message via the start
button.
The PL calls the Domain and tells it to generate a schedule. This call is probably to a domain service.
Your domain service is then in charge of populating the Job domain objects, creating a new Schedule domain object (or modifying an existing one), and returning the Schedule domain object.
Your PL then simply displays the returned Schedule.
This might be different if you just wanted to obtain an existing Schedule object. Instead of calling a domain service, you would ask a domain repository to get the existing schedule. The repository would be the way of encapsulating or otherwise obscuring the data layer from your PL and from your Domain.
Now, what you DON'T want to do:
Do not get the list of jobs in your PL, and then use that list of jobs to create the schedule in the controller of your MVVM. This would be business logic that defines your domain.
If Schedules are commonly generated from Jobs, regardless of whether it's called from MVVM or a PHP site, then don't add complexity in your PL and Domain Layer by forcing the PL to first get the jobs and pass them back into the Domain for a Schedule to be generated. The fact that those two concepts are tied to each other means that the relationship helps define your domain, and thus belongs in your domain layer. An exception might be when both the jobs and the schedule to be modified both rely on context from the front end (user input), but even this isn't always an exception.
Do not pass in VMs to your domain. Let your controller filter out the data and determine what needs to be sent to which domain part.
It's really hard to give a precise detail of what you should place where because only you would have a clear view of what defines your domain, but here's essentially how I break it down:
Could I change/replace this without affecting how my business/domain works?
If the answer is yes, it does not belong in your domain. Example: You could replace your entire MVVM front-end to flat PHP or ASPX, and even though it'd be a lot of work and a huge pain, you could to do it without affecting how the rest of the business operates.