I have a web service which I would like to call on a scheduled basis. Currently, I have a scheduled task setup to execute the call. Here's a link Jon Galloway's post on the topic.
I'm planning to switch this out with a Win Service, simply to appease my boss, but I'm wondering what the advantages are (aside from keeping my job ;).
I personally like the script method due to its simplicity, but am curious to know what I'm missing over a Win Service approach..
Reliability is higher with a Windows Service. It can be set to start when the system starts, and to restart automatically if it fails.
Related
My question is, is there a good way to push an integer value to a running windows service without restarting it and without writing to disk or having it poll some database?
Here's my scenario and a few thoughts:
I need to pass data to a windows service in real time I DO NOT want there to be a delay. All I need to give it is in integer and it can do the rest. My predecessor had it set up to poll a database every 10 min but that is no longer an option. I need the response time to be less than a second. I suppose technically I could just reduce the poll time to 0.5 sec but I'm thinking that would be bad for the database server. I know you can pass data to a windows service when it starts but restarting this service isn't an option because of what it's doing.
I would love to use a web service and just call a web method to pass in the data but the tasks require elevated (admin) permissions and almost everything involves file system access so my understanding is that a web service isn't really the best option either.
I've thought of using a hybrid scenario where I run a web service and a windows service on the same machine but then I still have the problem of how to pass the integer from the web service to the windows service... I could technically use a file system watcher but I really don't want to create a file just to pass an integer. I thought maybe I could use localDb and have the web service just write the value there and have the windows service poll localDb every 0.5 sec, But I'm not sure how much that polling would affect overall performance of other things. I really want a way to push data to the windows service rather than having the service poll somewhere else.
The project I work on has a front-end UI that communicates with a Windows Service running on the same system. In the past, I used the Windows Communication Foundation (WCF), but found this to be heavy-weight for what I really needed. I am now using a TCP socket over the localhost address (127.0.0.1) to exchange data between the UI and the service.
Based on your description, the web service approach seems heavy-weight, kinda like the WCF approach we used to use. And, as you've noted, it has permissions issues. A simple application that pushes the integer to your service over a socket would be straightforward in my mind.
If WCF is of interest, here's a couple links that might help:
Creating a user interface for monitoring and interacting with a running windows service
GUI and windows service communication
I am writing an ASP.NET web page which calls an API to update my client's property website using XML data. The data from the API is real-time, so I would like to run the page every 10 minutes.
Clearly I don't want to load my page manually to keep my client's property website up-to-date. There is a lot of help in Stack Overflow and elsewhere on this type of question but I have become a little overwhelmed by the options. I think that one way to go would be:
Windows Task Scheduler to fire every ten minutes (to trigger a VB.Net Service)
VB.Net Service (to run the web page)
My page runs..
That feels like overkill, and I haven't written a Windows Service or used the Task Scheduler and it feels like there should be 2 steps not three.
Now if I do use a VB.Net Service then I think that it might be better to give more work to the VB.Net Service rather than put my script in a web page, but I am used to writing web pages!
I can't help feeling that if I just keep the page open in a browser somewhere I can easily use JavaScript to run the page every 10 minutes, but that means ensuring it's open in a browser. Bad solution I think...
What I need is an overview of my options to make an informed decision and if it means learning then fine. Thanks in advance!
You can use javascript/Jquery to call a page/webmethod continously in timely manner
setInterval(function() {
// call your page or webmethod
}, 1000 * 60 * x); // x is your time interval in mins, in your case x=10
In my opinion the best approach would be to create a windows service and have the service call the web page. The windows service is much more stable than the Task Scheduler because the task scheduler can overlap if the previous Scheduled event did not finish. Also using the windows service gives you more control over error handling and logging
Get started with this link:
http://code.msdn.microsoft.com/windowsdesktop/CSWindowsService-9f2f568e
We have automatically started service which in some cases spends a lot of the time loading necessary data, let's say 10 minutes. During this time it works as expected (processing some huge data files required to start). I report the progess by C++ SetServiceStatus function, it is working fine.
This service is not dependent on anything and has only one dependency which is again our own service. It is started after those 10 minutes, it needs the first "server" service to be fully running to accept the requests.
I thought that windows would start all other automatic services (in less then 10 minutes as usually) and then start working normally but system is completely blocked during startup (i can't login to computer or ping the computer) until this one specific service is started (reports SERVICE_RUNNING by SetServiceStatus). When out service completely starts, the other missing system services (required for network, remote desktop, whatever, it's quite random) are also started. Is this normal behaviour? Why are non-depending processes (as remote desktop, network connections, etc.) waiting for this process? Am I missing something?
I tried to add some dependencies to postpone the startup of my service but I ended up with many dependencies and behaviour still somehow random (as order of services is random). Sometimes I was able to login but for example Start button started working only after those 10 minutes when my service was started. I am not sure what is "the last service" to depend on and what services to include to my depend-list and on some computers this services can be disabled and it can bring new problems... so I don't like this solution very much.
Another option was Delayed start option for our service. This should start service when all other automatic services are running. Well, this works fine, windows boots, computer running and responding, our service is started, but the performance is very bad, many times slower than usually, it seems that delayed started services have much lower priority or something like that.
My only current solution is to report to system that my service is running (by SetServiceStatus function), but to continue loading (this works, I tested it). But then we have problem with our dependent service as it needs to be started when the first one is really ready. It can be solved but I still wonder how is this possible and if there is something I could use to keep the current state of automatic started service which reports "started" when it is really fully started and prepared to work. Thanks for any ideas.
Set SERVICE_RUNNING as soon as possible, and then continue processing in background. Make your other service resilient to the first service being in a running state, but not yet ready to service.
The longer the service is in the starting state the more problems we get from different windows versions.
I want to make a tool that runs on win32 to monitor our online game servers. The servers actually are .exe files. I need to know whether they have crashed so I can restart them. Therefore, the tool will have 2 main features:
Frequently check a list of the server programs to see whether they are running or not
Reopen the executable of any server that has crashed
Does anyone have any idea or knows an API to start with?
If you're in Win32, you can start out with C# using System.Diagnostics
using System.Diagnostics;
Then get a process list:
Process[] processlist = Process.GetProcesses();
foreach(Process theprocess in processlist){
Console.WriteLine(“Process: {0} ID: {1}”, theprocess.ProcessName, theprocess.Id);
}
And from there it's up to you what you want to do with the info.
Game servers should produce logs. You should make a service / cron job to monitor the logs. Depends on the contents of logs, your service should act respective actions, e.g. restart service, trigger alarms, etc.
I realize that this is not exactly what you asked for, but what about doing the monitoring with a fully-fledged monitoring tool such as Nagios? You would of course have to "teach" the monitoring tool about the processes that shall be monitored but you would also profit from its more advanced functions. In the case of Nagios, for example, these would comprise automatic e-mail notifications, an online dashboard of process status, notifications via SMS etc.
You should start the game servers using CreateProcess or similar in the win32 api.
You will get back a process handle in the lpProcessInformation parameter.
You can use WaitForSingleObject to WaitForMultipleObjects to wait until that handle is notified which will happen when the process terminates for any reason.
I am wanting to write some web services using WCF.
I would like to have a "thread pool" in my web service.
For example, I have nearly 6gb of data I need to manipulate.
I would like the client to call an operation on the webservice and have a new task or thread created. The client is able to call a ListRunningTasks(); and have the webservice return a list of tasks. The client should be able to forcefully kill a task if it is taking too long e.g. KillTask(int taskID); or something. I have previously done some threading, but not inside WCF or a service that doesn't have state. Is this possible? If so, how would one go about implementing such a thing? Any reading, links or suggestions would be great.
Thanks, Mike.
One possible solution:
Implement explicit queues for your outstanding tasks taking into consideration that they take that long (20-30mins as you wrote).
Build a custom component to manage those queues e.g. you might even want capabilities to persist them, resume work when you restart the service etc.
Have explicitly created worker threads that pickup work from those queues.
Implement a WCF service to make your queue manager available to external systems.
Thread pools are more designed to process a high volume of short-running tasks.
You should consider using Windows Workflow Foundation to create such services. A state machine workflow can be exposed as a service in such a way that when method A is called, it will start the workflow (task), after which methods can be called to stop, suspend, or query the running task. WF will handle the state transitions, preventing illegal state changes, and making sure that new tasks are only spun up as necessary.
Note that WF will handle the threading issues for you in an almost transparent manner.