how does Quartz.net work in the background. suppose i have created a job which would get triggered next year. so what's happening in the background for one year. . Is there a process or thread which keeps running continuously for one year.does it implement timer in the background?
You need to start the Quartz scheduler. As long as the scheduler is running, Quartz will keep track of schedules and start jobs according to their schedule. But as Quartz is a library hosted inside your application, you have to start the Quartz scheduler yourself.
In scenarios where you don't have an application that is always active (like a website), you have to find some way to let the Quartz scheduler run independent of that (for instance in a scheduler service dedicated to running your jobs). I've found a few references to using Quartz.net in ASP.Net projects, but I have no personal experience with running Quartz within a website. I don't know how Quartz would react to IIS shutting down or reusing the application pool your site is running in. But if your job can handle being aborted, it may be a viable option. You'd have to start the scheduler in the Application_Start event in your Global class.
No matter how you run Quartz, you will want to use a non-volatile job store. Quartz can store the scheduled jobs in memory, but you'd have to re-schedule all jobs after each application start. So it is highly recommended to use another job store that can persist jobs between application restarts.
The Quartz.net quick-start tutorial has bits of code to show you how to use Quartz in your application.
Related
I'm looking at having a scheduled task (Console app) that will run every 20 minutes.
I've looked into using Quartz.Net for doing this, and it looks great but I can't see if it will work with my console application.
What I want is:
If I use only quartz.net then this console application will have to be open forever for my code to be run on schedule. Is there a way where I can have windows run my Quartz.Net scheduled task for me every 20 minutes?
So, Windows Task Schedular --20 mins--> run console app using Quartz.Net.
Or should I make a standard .NET Console App and just have it run the console app every 20 mins?
Cheers
Don't mix Task Scheduler with Quartz they are 2 different methods of doing things.
Normally Task Scheduler is configured at an interval to run Console Applications that just do the work and close.
The suggested way to use Quartz is to Embed it in in a windows service application.
Then install this service on the server and configure it to run always and automatic start (This should protect you from crashes and kills and ensure the application will be running always unlike a console application)
This is about ASP.NET MVC background. When I need to call action methods on timely basis, I use such 3rd part tools as HangFire, which runs under the application pool. I want to create a sync job, which reads a .csv file generated by our ERP system and update our custom DB.
But I know that having this sync job as an action method inside of my ASP.NET MVC is not the correct way of doing things, as background jobs should not be part of my web application.
So to handle my sync job I did the following :
Using Visual studio 2012 , I created a new console application and inside its main method I wrote the sync job as follow:-
class Program
{
static void Main(string[] args)
{
using (Entities sd = new Entities())
{
//code goes here
sd.SaveChanges();
}
}
}
How can I call this console application on timely basis? I am thinking on creating a new task using windows task scheduler, which would be executed each hour and call the application, mainly calls the .application file?
now my question is how i can call this console application on timely basis? . i am thinking on creating a new task using windows task scheduler , which will be executed each hour and call the application, mainly calls the .application file?
Running a program is one of the things the Windows Task Scheduler (TS) lives for. So yes, please do use the TS.
Additional benefits of using the TS are:
Able to specify the user account to run the process under
Multitude of ways to specify a trigger for when the task should run
Conditional mechanisms to control if the task should run (computer idle; power savings)
And a jolly nice history of the task when run
The alternative is creating you own scheduling service just to run your app but such a choice is frowned upon due to:
reinventing of the wheel
Windows gets flooded with an inordinate number of proprietary task scheduling services all essentially doing the same thing.
Background Jobs in Web Apps
Though one could arguably spawn/schedule a background thread/worker item in say ASP.NET to invoke some c# code, the danger here is that IIS is unaware that you have done so. It may decide to suspend or recycle your App Pool due to web inactivity and then your scheduled jobs would be sent to the void. Hence why it is not recommended.
Now you could always tell IIS not to timeout your App Pool so that it is not recycled periodically but I suspect that will lead to other issues.
Best not to do so in the first place.
However, there is nothing wrong in ASP.NET using the Task Scheduler API to schedule an operation to run say a console app.
Windows Task scheduler is a perfectly valid way to call a .net console application. I have several that I wrote and support that have been running for years with no issues.
I am developing an email marketing WinForm application. And for the scheduling of campaigns, I decided to use Quartz.NET. I need it to be running as a Windows Service. but I also want the user to be able to add a job (e.g. a campaign that needs to be run everyday at 8 AM which is basically running a .bat file) to the service through the program.
I am also saving all the job schedules in the database so that when you stop/start the OS or Windows Service it can still read from all the jobs that need to be run.
How can I add a job to the service while the service is running? The dynamic addition/removal of the job to the service is of course much preferred. Stopping the service and reading all the jobs again from the database is, to be frank, my last resort.
You can install Quartz.Net as a windows service and configure it to use AdoJobStore.
Your WinForm application will be the interface where you can add, suspend and remove jobs and triggers.
You do not have to stop your windows services while you're doing that.
You do not need to read your database to figure out what's happening in Quartz but you must use the APIs provided.
I've done something similar long time ago; my quartz.net "manager" was a web application.
You can read my answer here.
I guess the steps to do what you're looking for a pretty much the same.
Reference to Quartz.net samples and a free book can be found here and here.
I have a quartz.net scheduler implementation (and jobs). The scheduler is inside my website/application itself and runs jobs async at specified time intervals.
It is all very well on local and testing . As soon as i move this code to live (which has multiple load balancers running instances of my website), the jobs start firing as many times as there are load balancers.
How do i handle this? How do i make sure that there is just one scheduler that runs jobs across all my load balancers.
Alternatively is there a way for me to find out when was the previous job fired (on any of the load balancers!)
thanks
If you use a database as your job store, point all your schedulers at the same database and set them up as clustered, then your jobs will be shared across the servers and you won't have them firing multiple times.
Alternatively you could also move your scheduler out into it's own windows service and then share it across your web servers.
I have several important Quartz events that MUST go off at specific times of the night. Lately I have been noticing that not all the events are run. I have a feeling that overnight our server load is very light (ie. zero users) and that the web server kind of goes to sleep, and hence so does Quartz. Does this seem plausible? I am using Quartz.net within the web server, and not as a separate service.
Yes, that is plausible. In general, it is considered a bad practice to have IIS run scheduled tasks, that is a job better left for a Windows Service, or the built-in Windows Scheduled tasks (which has been much improved for Windows Server 2008).
Your worker process might have been shut down because there are no load. By default, IIS shuts down worker processes after 20 minutes without ingoing requests (you can alter this in the Application Pool settings). Also, worker processes are likely to be restarted after a certain amount of time or requests, or if they consume too much memory.
A quick-fix for your specific problem might be to use the Windows Task Scheduler to request the site periodically to keep it alive - or have it request a URL that triggers your task at the predefined time.
ASP.Net, by default, will shut down AppDomain's after a period of inactivity.
The recommended course of action is to implement timed events either in a Windows Service or as an executable launched from Window's Scheduled Tasks.
It is also possible to change the IIS configuration so that it will not shut down your AppDomain. How exactly this is accomplished varies between versions of IIS, but instructions can easily be found by searching.