Hangfire Shutdown Not Waiting to Kill Process - asp.net

We have configured Hangfire to run as part of our web app using OWIN as provided in the tutorial.
We enqueue long running background process via an API we provide. The job we run initializes a R process in the background using the.Net Process class. The R code internally spawns a number of processes internally to finish the job faster. We get a number of Rscript process running in Task manager when the job runs.
On manually Recycling the app pool of our web app(to see how process restart works) the Rscript Processes are not killed. We have a custom kill strategy we to get rid of all the Rscript process within our code.
while (IsNotTimedOut())
{
try
{
_token.ThrowIfCancellationRequested();
Thread.Sleep(2000);
}
catch (OperationCanceledException)
{
Kill();
throw;
}
}
Within the kill method, we block using Process.WaitForExit() method.
When we do the manual recycle all the process are not killed. The current thread instead of blocking for the process to kill just dies after killing a couple of Rscript processes.
The hangfire code seems to just cancel the token and it doesn't seem to wait for the process to get killed that are listening on the cancellation token. Please, can someone suggest how do we get this working, Please let me know if more details are required?

Related

How to stop a workflow immediately when a session fails?

I have a workflow that has many sessions that run in parallel to each other. When one of the session fails, the workflow waits for the other session to complete and then the entire workflow gets failed. We have selected the option "fail parent if this task fails". But we want the workflow to fail and stop immediately if any of the session fails without waiting for other sessions to finish.
ps: We have a unix shell script that calls all the workflows one by one. So if we can solve it using unix shell scripting that would be fine aswell.
Does anyone have any solution for it?
Best thing you can do in Informatica is use a Control Task to Abort the worklfow, and have it connected from all sessions with an OR condition. Something like:
start--S1--S2--S3
\ \ \
\---\---\-(OR)-CTL

Running process not shown in active process Instances and difference between ASYNC & SYNC tasks

My workflow is quite simple, I have two script, first script is ASYNC and the second is SYNC. In each script I have a loop from 0 to Integer.MAX_VALUE as follow
for(int i=0;i<Integer.MAX_VALUE;i++)
System.out.println("value is "+i);
When I run my process, it starts working and I can see in my log file that it is being filled. But when I want to stop it, I find nothing in my active process instances, neither in completed process or even in aborted. even if I check my data base, I have nothing related to this process in the ProcessInstanceInfo or even ProcessInstanceLog. So weird isn't it? what could be the reason?
The goal from creating this workflow is to see the difference between ASYNC and SYNC tasks, because as I know that ASYNC tasks when they start running, the workflow don't have to wait until this task finish, but what I have is that my task ASYNC is still running and it didn't go to next task. So my second question is can any one give me the difference between ASYNC and SYNC with a good example to learn. I would appreciate if I'll get at least one answer on one of my two questions. thanks
What do you stop? Do you abort the process instance ?
In the scripts you can populate the process variables with kcontext.setVariable("variable_name","variable_value"). This will reflect in DB if you have defined the process variable persistent in the process model.
The tasks, the sync one will return the flow control to the process when is completed. In contrast to the async one, process flow will continue immediately after it sends the async tasks to execute.

Gearman Worker start with ulabox symfony plugin

again, im stucking in Gearman. I was implementing the ulabox gearman Bundle which works nicely. But there are two things which I dont unterstand yet.
How do I start a Worker??
Im the documentation, I should first execute a worker and the start the code.
https://github.com/ulabox/GearmanBundle/blob/master/README.md
Open the first console and run:
$ php app/console gearman:worker:execute --worker=AcmeDemoBundle:AcmeWorker
Now open another console and run:
$ php app/console gearman:client:execute --client=UlaboxGearmanBundle:GearmanClient:hello_world --worker=AcmeDemoBundle:AcmeWorker --params="{\"foo\": \"bar\" }"
So, if I dont start the worker manually, the job would be done by itsself. If I start the worker, everysthin is fine. But at least, it is a bit strange to start in manually, even if there is set an iteration of x so that the worker will kill itsself after that amount of job.
So please, can anyone help me out of this :((((
Heeeeeelp :) lol
thanks in advance an kind regards
Phil
Yes to run some task in background not only Gearman need to be run but also workers.
So you have run "gearman" that wait for some command (e.x. email send).
Additionally you have waiting workers.
When gearman view new command he look for first free worker and pass this command to it.
Next worker process execution for command and after finish return to Gearman server that it finished and ready to process new command.
More worker you have faster commands in queue processed.
You can use "supervisor" for automatic maintenance workers running.
Bellow you can find few links with more information:
http://www.daredevel.com/php-jobs-with-gearman-and-supervisor/
http://www.masnun.com/2011/11/02/gearman-php-and-supervisor-processing-background-jobs-with-sanity.html
Running Gearman Workers in the Background

Symfony Process run as who?

When we using Symfony\Component\Process\Process, the command run as who?
I tried the command whoami through Process, but it return void???
$return = exec('whoami');
echo $return."\n"; // return [myname]
$process = new Process('whoami'); // The symfony process
echo $process->getOutput(); // return nothing #_#
Yes, it runs as user you run this command or the user of your webserver.
Your code seems a bit incomplete. I suggest adding $process->run(); before trying to get an output.
I almost guarantee that that Process runs as whatever user your webserver is running as. If you're running apache for instance, try running:
ps aux | egrep '(apache|httpd)'
In your terminal to discover which user apache is running as. My money would be on either apache or httpd as the user which Process runs under. Hope that helps.
From the documentation is better use start() instead run() if you want to create a background process. The process_max_time could kill your process if you create it with run()
"Instead of using run() to execute a process, you can start() it: run() is blocking and waits for the process to finish, start() creates a background process."

Pagodabox or PHPfog + Gearman

All,
I'm looking for a good way to do some job backgrounding through either of these two services.
I see PHPFog supports IronWorks, but i need something more realtime. Through these cloud based PaaS services, I'm not able to use popen(background.php --token=1234). So I'm thinking the best solution, might be to try to kick off a gearman worker to handle the job. (Actually my preferred method would be to use websockets to keep a connection open and receive feedback from the job, rather than long polling a db table through AJAX, but none of these guys support websockets)
Question 1 is, is there a better solution than using gearman to offload the job?
Question 2 is, http://help.pagodabox.com/customer/portal/articles/430779 I see pagodabox supports 'worker listeners' ... has anybody set this up with gearman? Would it work?
Thanks
I am using PagodaBox with a background worker in an application I am building right now. Basically, PagodaBox daemonizes a PHP process for you (meaning it will continually run in the background), so all you really have to do is create a script that checks a database table for tasks to run, runs them, and then sleeps a bit so it's not running too many queries against your database.
This is a simplified version of what I have running:
// Remove time limit
set_time_limit(0);
// Show ALL errors
error_reporting(-1);
// Run daemon
echo "--- Starting Daemon ---\n";
while(true) {
// Query 'work_queue' table for new tasks
// Loop over items and do whatever tasks are associated with them
// Update row to mark task as completed
// Wait a bit
sleep(30);
}
A benefit to this approach is that it's easy to test via CLI:
php tasks.php
You will see all the echo statements come through in console as it's running, and of course it's much easier to do than a more complicated setup with other dependencies like Gearman.
So whenever you add a new task to the table, the maximum amount of time you'll wait for that task to be started in a batch is 30 seconds (or whatever your sleep time is). This is better and preferable to cron jobs, because if you setup a cron job to run every minute (the lowest possible interval) and the work you have to do takes longer than a minute, another cron process will start working on the same queue and you could end up with quite a lot of duplicated task work that could cause a lot of issues that are hard to debug and troubleshoot. So if you instead have either only one background worker that runs all tasks, or multiple background workers that work on different task types, you will never run into this issue.

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