I'm trying to gain some understanding and experience in creating background processes on Azure.
I've created a simple console app and converted it to Azure Worker Role. How do I invoke it? I tried to use Azure Scheduler but looks like the scheduler can only invoke a worker role through message queues or HTTP/HTTPS.
I never thought about any type of communication as my idea was to create a background process that does not really communicate with any other app. Do I need to convert the worker role to a web role and invoke it using Azure Scheduler using HTTP/HTTPS?
Worker role has three events:
OnStart
OnRun
OnStop
public class WorkerRole : RoleEntryPoint
{
ManualResetEvent CompletedEvent = new ManualResetEvent(false);
public override void Run()
{
//Your background processing code
CompletedEvent.WaitOne();
}
public override bool OnStart()
{
return base.OnStart();
}
public override void OnStop()
{
CompletedEvent.Set();
base.OnStop();
}
}
The moment you run/debug your console converted worker role. First two (OnStart & OnRun) fires in sequence. Now in OnRun you have to keep the thread alive, either by using a while loop or using ManualResetEvent this is where your background processing code would live.
OnStop is fired when you either release the thread from OnRun or something un-expected goes. This is the place to dispose your objects. Close unclosed file-handles database connection etc.
Related
I start Camel Main Standalone application using Unix Scheduler.
It initiates Routes; But as i have Thread.sleep(time) after context.start().
Now application first execute; whatsoever in routes; and when route finish processing(stop(), application still working and finishes when thread.sleep time over.
Any idea how to completely stop the standalone application after my route finish process?
Following is code snippet for reference:
SimpleRegistry sr = new SimpleRegistry();
sr.put("masterdata", dataSource);
CamelContext context = new DefaultCamelContext(sr);
try {
context.addRoutes(new RouteBuilder() {
#Override
public void configure() throws Exception {
from("timer://alertstrigtimer?period=60s&repeatCount=1")....
from("etc").....
from("etc").....
from("etc").stop()
}})
context.start();
Thread.sleep(30000);
} catch (Exception e) {
LOGGER.warn("configure(): Exception in creationg flow:", e);
}
Is any way within camel or may be in java to kill the thread after camel route stop all processing.
You have different options, here some I would consider:
use camel-main and configure it to shut-down when a certain amount of the exchanges are done
use a route policy and shut-down the camel context according to your own rule
Trying to get Azure Webjobs to react to incoming Service Bus event, Im running this by hitting F5. Im getting the error at startup.
No job functions found. Try making your job classes and methods
public. If you're using binding extensions (e.g. ServiceBus, Timers,
etc.) make sure you've called the registration method for the
extension(s) in your startup code (e.g. config.UseServiceBus(),
config.UseTimers(), etc.).
My functions-class look like this:
public class Functions
{
// This function will get triggered/executed when a new message is written
// on an Azure Queue called queue.
public static void ProcessQueueMessage([ServiceBusTrigger("test-from-dynamics-queue")] BrokeredMessage message, TextWriter log)
{
log.WriteLine(message);
}
}
I have every class and method set to public
I am calling config.UseServiceBus(); in my program.cs file
Im using Microsoft.Azure.WebJobs v 1.1.2
((Im not entirely sure I have written the correct AzureWebJobsDashboard- and AzureWebJobsStorage-connectionstrings, I took them from my only Azure storage-settings in Azure portal. If that might be the problem, where should I get them ))
According to your mentioned error, it seems that you miss parameter config for ininitializing JobHost. If it is that case, please use the following code.
JobHost host = new JobHost(config)
More detail info about how to use Azure Service Bus with the WebJobs SDK please refer to the document.The following is the sample code from document.
public class Program
{
public static void Main()
{
JobHostConfiguration config = new JobHostConfiguration();
config.UseServiceBus();
JobHost host = new JobHost(config);
host.RunAndBlock();
}
}
I am running a Masstransit (using rabbitMQ) within a Topshelf Windows Service. How can i force stop the topshelf service whenever there is exception in consumer ie. from the FaultConsumer?
Thanks
Hang on to the HostControl argument that is passed to the Start() method of the ServiceControl interface. If at any time you need to request the service be stopped, call the Stop() method.
public interface ServiceControl
{
bool Start(HostControl hostControl);
bool Stop(HostControl hostControl);
}
public interface HostControl
{
void RequestAdditionalTime(TimeSpan timeRemaining);
void Stop();
void Restart();
}
I'm confused about how to continue writing my program.
Basically, it connects to multiple serial devices, and then updates the javafX Application based on the responses from the devices (I first have to send the machine a message). So what I did was create a thread to run in the service thread, so that my program would not freeze and the Thread could pause until the message is read (there's a delay between sending and receiving a message over the serial device).
service = new Service() {
#Override
protected Task<String> createTask() {
return new Task<String>(){
#Override
protected String call() throws Exception {
new Thread(thread).start();
return null;
}
};
}
};
Where the thread does some loop, continuously sending and reading messages.
#Override
public synchronized void run() {
while(serialOn && isRunning){
sendMessages();
}
}
public synchronized void sendMessages(){
sendSerial1();
this.wait();
sendSerial2();
this.wait();
}
public synchronized void readMessage1(){ // same readMessage2 for the sendSerial2()
getMessage(); // updates variables that are bound to the Javafx App
this.notify();
}
But, I think the service finishes (i.e. succeeds or fails) before it event starts my serial thread. But I want the service to continue running while the program sends and receives messages.
Let me know if you need more code, it's a little long and requires the serial devices to run, but I can include it here if it makes the question easier to understand.
Don't create a new thread in the call() method of the service's Task.
A service automatically creates threads on which the call() will be invoked. If you want control over the thread creation and use, then you can (optionally) supply an executor to the service (though in your case you probably don't need to do that unless you don't want the service to be a daemon thread).
From the Service javadoc:
If an Executor is specified on the Service, then it will be used to actually execute the service. Otherwise, a daemon thread will be created and executed.
So shift the code inside the run() method of your Runnable and put it into the call() method of the Task for the Service (the Task itself is a Callable, which is a Runnable, so having an additional Runnable is both redundant and confusing).
I am wondering why the following azure workerrole does not show any diagnostic messages when the role is shutdown:
public class WorkerRole : RoleEntryPoint {
private bool running=true;
public override void Run() {
while (running)
{
Thread.Sleep(10000);
TTrace.WriteLine("working", "Information");
}
Trace.WriteLine("stopped", "Information");
}
public override bool OnStart()
{
Trace.WriteLine("starting", "Information");
return base.OnStart();
}
public override void OnStop() {
Trace.WriteLine("stopping", "Information");
running = false;
base.OnStop();
}
}
I can see the events 'starting' and 'working' in the diagnostic logs, but the Onstop method does not log anything. I was wondering if it's even called so I injected some code in the OnStop() method to write out some data. In fact the data was written as expected which proves that the method is called, it's just that I don't get any logs. Any ideas how to Trace my shutdown code?
My first and best guess is that the Diagnostics Agent does not have time to transfer the trace out to storage for you to see it. Traces are first logged locally on the VM, then the agent will transfer them off (OnDemand or Scheduled) depending on how you have configured it. Once the VM shuts down, the agent is gone too and cannot transfer it off.
Tracing in OnStop is not supported and if you manage to get it working via On-Demand Transfer (http://msdn.microsoft.com/en-us/library/windowsazure/gg433075.aspx ) it's likely to not work in the next release. Note, tracing in Web Role OnStart does not work either. See my blog post http://blogs.msdn.com/b/rickandy/archive/2012/12/21/optimal-azure-restarts.aspx to fix that. Also see my blog post for instructions on view real time OnStop trace data with DbgView.
The OnStop method should be used only to delay shutdown until you've cleaned up - so you shouldn't have much code in there to trace. Again, see my blog for details.