I have a requirement in hand where I need to change the Mule Flow Threading Behavior at runtime without the need of bouncing the whole Mule Container. I figured out few different ways to achieve this, but none of them are working.
I tried accessing the Mule Context Registry and from there I was trying to do a lookup of "FlowConstructLifecycleManager" Object so that I can tap in there and access the threading profile of the object and reset those values, then stop and start the flow programmatically in order to get the change applied in the flow. I am stuck in this approach as I was unable to get hold of the FlowConstructLifecycleManager Object neither from the Mule Spring Registry nor from the Transient Registry. I was able to get hold of the Flow object though which has a direct reference to that FlowConstructLifecycleManager Object. But, unfortunately, they made this object as protected and didn't expose any method for us to access this object.
Since I was unable to access this FlowConstructLifecycleManager directly from Mule implemented Flow class, I decided to extend this Flow class and just add another public method to it so that I can access FlowConstructLifecycleManager object from Flow object programmatically. But, I am stuck in this approach as well as even if I am putting my version of the same Flow class packaged and dropped in lib/user folder of the container, it is still not picking up my version of the class, and loading the original version instead.
It would be of great help if I can get any pointer on the approach of solving either my first or second problem.
Thanks in advance,
Ananya
In our company, we are building a dashboard from where we should be able to start/stop any flow or change the processing power of any flow by increasing/ decreasing the active threads for a flow or changing the pollen polling frequency. All of these should be done at runtime without any server downtime.
Anyway, I made it working finally. I had to patch up the mule-core jar and expose few objects so that I can get to the thread profile object and tweak the values at runtime and stop/ start the flow to reflect the changes to take effect. I know this is little bit messy and but it works.
Thanks,
Ananya
Related
I'm trying to create a custom build of noflo-ui that is effectively only a graph editor. Don't need it to connect to any runtimes.
I'm struggling to find where I can inject this code as it appears part of noflo-ui is written in noflo itself and I cannot find the scripts for those pieces.
For example, in graphs/main.fbp, there is this line:
'user,main,project,github,runtime,context' -> ROUTES Dispatch
Three questions on this:
Where is the source behind the Dispatch component?
If I add my own interface elements to Load data from an external api, where would be the best place to inject that data?
I see a lot of event driven code, so I'm guessing I would add a new polymer element, do my ajax call, the emit or fire something. I believe this is what happens when connecting to a noflo-nodejs runtime; I've traced the connection to line 51312 in a built noflo-ui.js
return port.send({
componentDefinition: definition
});
... but I can't figure out where it goes past here. A port on the main.fbp graph? As per my 1st question, I cannot find the source behind these core graphs.
And this leads to my last question
The code I pasted above from noflo-ui, I cannot find this code anywhere pre-build. I even searched the entire project tree for "componentDefinition: definition". Where is this coming from?
Any pointers on this would be greatly appreciated! Thanks
The FBP runtime protocol is the primary extension point of noflo-ui. You can implement a "runtime" which just provides components and graphs (for instance from a database), without a way to run these.
A network:persist message to let the UI indicate that "this is a good point to save the graphs" has been specced but is currently not implemented. For now you can just autosave latest state.
Two views in my application need to load same information when restoring state. My idea was, to avoid saving it twice, to have one view create another in init orcreatePartControl if it wasn't created yet. However,
PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage().showView(...)
doesn't work there, as getActivePage() returns null. Is it possible to work around this?
Delegate to a manager or service to load/maintain/save the shared state. That will ensure the first access initializes your information. When the view is instantiated just go to the manager and retrieve the information. If the user never instantiates your view, then you never had to do the extra work.
In the general case, you can't create/instantiate one view while creating/activating another view. Eclipse won't allow it, and will generate ERRORs in the error log.
EDIT:
3 standard persistence patterns I've seen used (and/or misused :-) are:
1) Have your plugin get its state location and simply serialize you state out there. (location provided for free if you subclass org.eclipse.core.runtime.Plugin) You can do it in your activator stop(BundleContext) method. You can uses classes like org.eclipse.ui.XMLMemento to serialize to/from XML if you don't already have a solution.
2) if you subclass org.eclipse.ui.plugin.AbstractUIPlugin you can use org.eclipse.ui.plugin.AbstractUIPlugin.getDialogSettings() to store your state. Potentially a little bulky as you would have to keep it up to date.
3) have your common manager update a preference, potentially using another serialization technique.
I've spend days trying to find a solution the problem i'm going to try to describe, i've googled alot and even looked at the .NET 4 reference source for SendReply and InternalSendReply activity. But until now i'm stuck.
To make the life of our end customers simpler i want to replace the Receive and SendReply activities with custom activites and use bookmarks instead.
I'm implementing a central webservice which can route to a correct workflow instance, that workflow modifies the bookmark value and finaly it creates a new bookmark while returning the modified bookmark value. It's rather complex already with a WorkflowServiceHostFactory which adds Behaviours and Attach a DataContractResolver to the endpoint.
The endpoint is derived from WorkflowHostingEndpoint which resolves a bookmark created in a custom activity (instead of a receive). And i want another activity instead of a sendreply. Those 2 should correlate and the custom sendreply does send a response on the open channel through the endpoint while creating a new bookmark.
The problem is that i didn't find a way yet to access the endpoint responseContext from within my custom send activity. On the other side, at the workflowcreating endpoint side, it seems that i'm not able to be notified whenever the workflow becomes Idle and as well i don't seem to be able to access the WorkflowExtensions from the host. i'm missing something?
A possible solution i've in mind might be not using a WorkflowServiceHost, but then i loose alot of AppFabric functionaly.
The workflowapplication in platform update 1 has some extension methods called RunEpisode with an overload Func called idleEventCallback. There it's possible to hook into the OnIdle and get a workflowextension to get the object to send back as response.
To answer my own question, i ended up in a workaround using the servicebroker functionality of sql server. The SqlDependency class where the workflow listens for the event to be fired whenever the workflow reach the activity that creates a new bookmark in another state.
Currently I am struggling with a Entity Framework issue. I have a wcf service that sits on top of the ef framework, and allows queries to the framework. At some point the user is able to request a file from the framework. The files are referenced by solution entries, so when you request a file from a solution, the reference is loaded to gain access to the file store.
That all works fine, but from that point onward, whenever you do another query that returns that solution entry, the whole file gets attached to the return result. I need some way of detaching or unloading the reference, such that the result entries will only contain an unloaded reference to the file store again.
I have tried to create a new context and query that context to retrieve information from, but when I do that, the entity in the original context is also changed.
I have tried to detach the entity from the original context and then query from the new context. That does not work either.
I have found one way of doing this. For all the non file-download queries, I detach the result entity, and send that over the wire. I am not sure if that is the best way to go about it though.
I hope someone might be able to provide some insight, thanks for the effort.
The issue you are experiencing is probably do to Change Tracking, which is on by default.
Possible Solution:
Disable Change Tracking with MergeOption.NoTracking
using (MyEntities _context = new MyEntities())
{
_context.Widgets.MergeOption = MergeOption.NoTracking;
return _context.Widgets.ToList();
}
This article may help to point you in the right direction on how to handle this issue if the solution above does not work.
I struggled with a similar issue recently. The problem was the result of the context maintaining a reference to the object I was using (obviously). Every time I made a change to an object of the same type, even when obtained with a new context (so I thought), the object was being changed.
With help from one of my peers, we determined the context was hanging around due to the way I was registering it with my IoC container (lifestyle per web request). When I changed the lifestyle to transient (which definitively provided a new instance) then changes to objects of the same type were unaffected.
Hope this helps.
I'm working on a small application using C++/wxWidgets, where several parts of the GUI need to be updated based on e.g. received UDP datagrams. More specifically, a secondary thread tries to keep a list of available "clients" in the network (which may come and go away) and e.g. corresponding comboboxes in the UI need to be updated to reflect the changes.
The documentation mentions that for this kind of thing EVT_UPDATE_UI would be a good choice. As far as I can understand from the sparse documentation, this event is sent automatically by the system and provides some support for assisted UI change.
However, I'd feel more comfortable using a more direct approach, i.e. where e.g. a window object could register/subscribe to receive notifications (either events or callbacks) upon particular events and another part of the code is sending out these notifications when required. I could do this in C++ using my own code, however I guess if wxWidgets already supports something like that, I should make use of it. However I haven't found anything in that regards.
So, the question is: does wxWidgets support this kind of notification system (or similar alternatives) or would I be best served coding my own?
AFAIK there is nothing directly usable in wxWidgets, but doing it on your own seems easy.
What I would do:
Create a wxEvtHandler-descendent class to hold the list of available "clients" in the network. Let this class have a wxCriticalSection, and use a wxCriticalSectionLocker for that in all methods that add or delete "clients".
Create a worker thread class by inheriting wxThread to handle your UDP datagrams, using blocking calls. The thread should directly call methods of the client list object whenever a client has to be added or removed. In these methods update the list of clients, and ::wxPostEvent() an event to itself (this will execute the whole notification calls in the main GUI thread).
Handle the event in the client list class, and notify all listeners that the list of clients has changed. The observer pattern seems to me a good fit. You could either call a method of all registered listeners directly, or send a wxCommandEvent to them.
Have you tried calling Update() on the widget(s) that change? Once you update the contents of the combo box, call Update(), and the contents should update.