I’m working on a windows app composed of two parts:
An agent, running in the background.
A main application with a window to start/stop the agent and configure it.
What I understand is that I should use a “windows service” for the agent.
But I’m not sure how this is supposed to be packaged? (Can I have these two parts in the same .exe?)
And how the agent and the main application can communicate (should I use a shared file? Can my agent have a private folder to work in?)
I’m looking for some architecture advices basically
Running the agent as a service is probably the best way to go. It'll run without anyone needing to be logged in to run it, and Windows provides extensive monitoring support for services. You can use the sc command to install, start and stop a service, and it even supports controlling services on other machines if you've got the appropriate permissions.
In order to have your gui communicate with it you could look at using WCF. It will allow you to define your interactions with the service as C# classes and will save you having to worry about checking shared directories or looking into a shared file etc. This approach will also make it easy to support multiple clients at the same time, whilst something like a shared folder approach will make this difficult.
You will need to have to separate .exe files, one for the service and one for the windows application. You can package these are two separate MSIs within Visual Studio, the benefit here is that if you need to move the service (for whatever reason) you are not then also packaging up the Windows App and leaving it where ever you install the service.
There are different ways you can have them communicate without getting massively complex. you could read from a text file, as you've suggested, but this could cause locking problems. When I've had to do similar I created a simple database in SQL (or any brand of database you wish), and have the Windows App insert / update configuration options to a table, and the service then reads the table to get its settings.
Related
I have a Windows Forms Application which runs on a server. I need this Application to always start automatically. Even if the Server just gets restartet and nobody logs into it the Application should run.
So the solutions with Registry don´t work here. I than read into Windows Services but it seems like I can´t start a WinForm Application with it.
Does anyone have an idea how I can achieve this automatic Start on Server startup?
The way we do things like that is that we create a Windows Service which runs without the need to have anyone logged in, and then if there is a need we have a separate GUI application (WinForms in your case) which interacts with the service, when needed.
The communication between the GUI application and the Windows Service is usually done by means of named pipes, but if you can get away with something simpler, like the GUI application saving a configuration file for the service to pick up, you might make it easier for you.
TL;DR: I have a service, a gui, and a tray icon. I want to know how to get the tray icon to run on user login/start-up and be able to stop the service and start the gui
Some Background Info:
I have a windows service I've made that uses a xml file to collect
files from other computers on my network and store them on the local
pc (running the service). the xml has some structures called
'profiles' which have info like FileDestination, LocationToTakeFrom,
FileTypeToTake, and IsProfileActive...
The service basically takes all the active profiles and every hour
scans the location for files created within a 1hr window of the
current date/time on local PC.
My GUI allows the user to make profiles / modify profiles, as
well as determine which profile(s) should be active for collection. I
dont want this gui running at all times, so I plan to have a
systemTrayIcon to allow this GUI to be opened and shutdown.
I'm using Visual Studio 2010 .NET 4.0 everything is in C#, I have 1 solution with separate projects(gui and service)
I'm wondering about the following things as far as the System Tray Icon goes:
1) how do I have the icon start on user login (note that this will be distributed via an installer, not just my personal use. so It has to be done via code)
2) Stop a service via sysTrayIcon
3) where to place the SysTrayIcon... do I make a 3rd project? add it in the GUI project? not quite sure here.
4) if SysTrayIcon IS in a seperate project how can I have it create instances of the GUI?
ie how can I start the GUI application from code in a different project
the project requirements are:
-upon installation the GUI must start, after that the Gui should only be accessed through the tray icon.
-user should be able to stop the service any time via system tray icon
Start the client
There are plenty of ways to start an application on Login under Windows. Just grab SysInternals AutoRuns to get an idea. The obvious ones are (a) the good ol' Startup group and (b) one of the
\SOFTWARE\Microsoft\Windows\CurrentVersion\Run*
keys under HKCU and/or HKLM. That's the typical task of an setup utility, which makes sense since you have to install the service anyway. To do it in code:
Registry: Open the reg key, add the entry, close the reg key.
Startup: determine the value of CSIDL_STARTUP or CSIDL_COMMON_STARTUP using SHGetFolderPath, then create a Shell Link in that folder.
Service communication & control
The GUI part implements the TrayIcon and communicates through some channnel with your service. Again, there are plenty of possibilities how to do this, like disk files or memory mapped files, named pipes, even sockets. It would be too broad to list all the ways here, so I'd suggest to decide for one way and ask again if you have specific questions on that one.
To stop your service from code, use the ControlService() function and pass SERVICE_CONTROL_STOP as the dwControl parameter. To start a service, there's another function named (big surprise) StartService() to achieve that. Note that you may need to start an elevated copy of your app to control services. A quick & dirty way is to simply launch net start/stop MyService elevated with the necessary args.
I am writing a windows service to process emails on a daily basis. This service includes a App.Config file, which has several parameters for the service to work accordingly.
Every time, the admin user has to go and change / add / delete the pair inside the section using a text editor.
I am planning to include a windows form to load all the pair from the section and thinking of doing any modification through the form.
All I would like to know is whether it's possible to have a winform inside a windows service and open it when ever the configuration needs to be changed? I know we can have a seperated windows application and load the App.Config file of the windows service. I just want to avoid having a seperate app for this.
If you have done something very similar to this, please share your thoughts!
Regards,
Sriram
That sounds like a security issue if nothing else.
A Windows service runs in a different context and account and cannot interact with the desktop unless specifically allowed when installing the service. This is not enough of course so you'd also have to have the service running under the same account that is running the desktop - this in itself is really bad design and not something I would recommend.
You could also have the service executable decide what to do during launch, a common pattern is to have it spawn as a console application when debugging to simplify development. But then you'd have to stop the service and launch the service executable manually interactively to get the UI behaviour.
In any way, a separate configuration tool is the way to go.
What are some best practices for being able to deploy a Windows service that will have to be updated?
I have a Windows service that I will be deploying but might require some debugging and new versions during the beta process. What is the best way to handle that? Ideally, I'd like to find a ClickOnce-style deployment solution for Windows services but my understanding is that this does not exist. What is the closest I can get to ClickOnce for a Windows service?
A simple solution that I use is to merely stop the service and x-copy the files from my bin folder into the service folder.
A batch file to stop the service then copy the files should be easy to throw together.
Net stop myService
xcopy \\myServerWithFiles\*.* c:\WhereverTheServiceFilesAre
net start myService
I have a system we use at work here that seems to function pretty well with services. Our deployed system has around 20-30 services at any given time. At work we use a product called TopShelf you can find it here http://topshelf-project.com/
Basically TopShelf handles a lot of the service related stuff. Installing, Uninstalling etc all from the cmd line of the service. One of the very useful features is the ability to run as console for debugging. You build one service, and with a different cmd line start you can run it as a console to see the output of the service. We added one custom feature to this software that lets us configure profiles in advance. Basically our profiles configure a few things like logging, resource locations etc so that we can control all that without having to republish any code. All we do is run a command like
D:\Services\ServiceName.exe Core.Profiles.Debug or
D:\Services\ServiceName.exe Core.Profiles.Production
to get different logging configurations.
Our build script creates install.cmd and uninstall.cmd scripts for each of our services all we do is copy the files to the server and run the script. If we want to see debug output we stop the service and double click the exe and we get a console to read all the output.
One more thing that topshelf has which we don't use because its not necessary is the concept of shelving (there is documentation on this website for this). This allows you to update the service without having to "restart" but you still need to copy the files manually unless you build an automated system for that.
However, my suggestion if you need 100% service availability is to have a redundant system. No matter how you configure your service for updates you cannot avoid hardware failure causing downtime without an automated failover system. If said system was in place my recommended update strategy would be to turn off 1 node, update, test, turn on turn off the other node, update, test and turn the 2nd node back on. You can do this all of course with a simple script. This may be a more complicated system than you need but if you can't take a service offline for a simple restart that takes 5 seconds then you really need some system in place to deal with hardware issues because I can guarantee it will happen eventually.
Since a service is long-running anyway, using ClickOnce style deployment might not be viable - because ClickOnce only updates when you launch the app. A service will typically only be launched when the machine is rebooted.
If you need automatic update of a service then your best bet might be to hand-code something into the service, but I'd forsee problems with almost any solution: most install processes will require some level of user interaction (if only to get around UAC), so I can't imagine this would lead an answer that doesn't involve getting a logged-on user in front of the screen at some point.
One idea that might just work is active-directory deployment (or some similar equivalent). If your service is deployed via a standard MSI-type installer, AD allows you to update the application silently as part of the computer policy. I suspect you'd have to force the server to refresh the AD policy (by rebooting or using gpupdate from the console), but other than that it should be a hands-off deployment.
I would suggest using the "plugin" approach on this, that is, using the Proxy Design Pattern.
While using this pattern, an independant thread may verify over a folder for updates. You will need to use ShadowCopy over your assembly deployment. When your service update-thread encounters a new version of your service, it shall unload the current production assembly and load the new version, without stopping the service itself. Even more! Your service should never notice the difference, if there is no breaking code within your assembly.
I would suggest to create a normal setup project, and add the windows service project output in that setup project.
For more information please refer to http://support.microsoft.com/kb/816169.
I have an application that manages the heavy processing for my project, and need to convert it to a "Windows Service." I need to allow running multiple versions instances of the application processing, which seems to be a fairly normal requirement.
I can see at least three approaches to do this:
Create a single installed directory (EXE, DLLs, config) but install as multiple Services instances from it.
Have a single Services instance spawn multiple instances of itself after launching, a la Apache.
Have a single Services instance spawn multiple threads that work within the same process space.
My intention was approach #1, but I kept tripping over the limitations, both in design and especially documentation for Services:
Are parameters ever passed to OnStart() by the normal Services mechanisms on an unattended system? If so, when/why?
Passing run-time parameters via the ImageKey registry seems a kludge, is there a better mechanism?
I got the app to install/uninstall itself as a pair of services ("XYZ #1", "XYZ #2", ...), using the ImageKey to hand it a command line parameter instance number ("-x 1", "-x 2") but I was missing something. When attempting to start the service, it would fail with "The executable program that this service is configured to run in does not implement the service.
So, the questions:
Is there a concise description of what happens when a service starts, specifically for those situations where the ServiceName is not hard-coded (see Q above).
Has anyone used approach #1 successfully? Any comments?
NOTE: I've side-stepped the problem by using approach #3, so I can't justify much time figuring this out. But I thought someone might have information on how to implement #1 -- or good reasons why it isn't a good idea.
[Edit] I originally had a 4th option (install multiple copies of the application on the hard drive) but I removed it because it just feels, um, hackish. That's why I said "at least three approaches".
However, unless the app is recompiled, it must dynamically set its ServiceName, hence that has the solution to the third bullet/problem above. So, unless an instance needed to alter it's install files, #1 should work fine with N config files in the directory and a registry entry indicating which the instance should use.
Though I can't answer your questions specific to option #1, I can tell you that option #2 worked very well for us. We wanted to create an app domain for each 'child' service to run under and for each of them to use a different configuration file. In our service's config file we stored the app domains to start and the configuration file to use. So for each entry we simply created the app domain, set the configuration file etc and off we went. This separation of configuration allowed us to easily specify the ports and log file locations uniquely for each instance. Of additional benefit to us was that we wrote our 'child service' as a command-line exe and simply called the AppDomain's ExecuteAssembly() on a new thread for each 'child' service. The only 'clunk' in the solution was shutdown, we didn't bother to create a 'good' solution for it.
Update Feb, 2012
Some time ago we started using 'named' services (like SQL Server). I detailed the entire process on my blog in a series "Building a Windows Service – Part 1 through Part 7". They take you through creating a command-line/windows service hybrid complete with self-installation. The following goals where met:
Building a service that can also be used from the console
Proper event logging of service startup/shutdown and other activities
Allowing multiple instances by using command-line arguments
Self installation of service and event log
Proper event logging of service exceptions and errors
Controlling of start-up, shutdown and restart options
Handling custom service commands, power, and session events
Customizing service security and access control
A complete Visual Studio project template is available in the last article of the series Building a Windows Service – Part 7: Finishing touches.
Check this out: Multiple Instance .NET Windows Service
There is option #4 that I'm successfully using in my project aka "named instances".
Every installation of your app has custom name and each installation has its own service. They are completely independent and isolated from each other. MS SQL Server is using this model if you try to install it multiple time on single machine.