For my projects I need quite often to create windows services.
I need them for scheduling operations, file system watching, asynchronous or long running side tasks (backup files, sending messages, check incoming mail to process, notifications etc).
I also use them to expose WCF services that are cross applications in the enterprise.
The self hosted scenario seems to me more appropriate as we are still on II6 that is quite limited (only http) for exposing WCF.
Most of) the services need also to expose some kind of administration interface (web or desktop) for reporting, starting and stopping the various services etc.
Seems strange to me that a "host container" that leverages most of these features (host, install new services, remote ui for admin, exposing wcf, scheduling etc) with some kind of mef plugins doesn't already exists.
What are the options if I do not want to start from scratch?
I am a developer for an open source windows service hosting framework called Daemoniq. I understand how installers can be an inconvenience so creating installers on the fly is one of its features. You can download it from http://daemoniq.org
Current features include:
container agnostic service location via the CommonServiceLocator
set common service properties like serviceName, displayName, description and serviceStartMode via app.config
run multiple windows services on the same process
set recovery options via app.config
set services depended on via app.config
set service process credentials via command-line
install, uninstall, debug services via command-line
Please feel free to have a look at it. Code contributions are also welcome =D
Thanks!
There is one host server in development (Microsoft) - codename Dublin.
The possible option would be to create one Windows Service - host application, which will load all of your WCF services and create ServiceHost for each of them (for instance, through reflection).
Having only one windows service would make it easy to administer all service hosts (you wouldn't have to administer windows service, but only in-process hosts).
Related
I have a couple of wcf services which will call a registration service at startup (through a custom ServiceHostFactory). All these services (including the registration service) are running in the same app pool. I installed appfabric to auto-start all the services. I won't explain all the detailed settings (because I think it's not necessary yet), but in short, the services use net.tcp bindings and is running in IIS 7.5 on Windows 7.
The problem:
When I set all services to auto-start it will begin with one (random) service, this service tries to connect to the registration service. But somehow this registration service won't start-up. It looks like it wants to start all services sequentially.
The (not wanted) solution 1:
When I put the registration service in it's own app pool everything works fine and alle services come online in a matter of seconds and register themself.
The (not wanted) solution 2:
When I disable the auto-start and try to access one of the services after a iisreset, it all works fine. The service will try to register itself and the registration service in his turn will start.
I'm new to appfabric, so it might be some simple configuration issue. The weird thing though is that it won't work whith auto-start, but seems to work fine with a manual start.
Any idea's?
There is no priority in AppFabric Auto Start feature. You can't assume that one service will always be started before the others. Also, you can't assume they will start all at the same time.
For the specific scenario, it's recommanded to use WCF 4.0 Discovery and Announcement. Announcement feature enables service to announce their availability (by sending Hello and Bye announcements) whereas Discovery feature allow clients to discover service address at runtime.
All your services are on the same server ? could be pertinent to use a namedPipeBinding.
I need to create a Windows Service to watch a folder on our network and action files that are placed within it. The process is quite slow and I need the ability to check the progress from a client application (which will be running in about 10 places on the same network as the machine running the Windows service).
Is hosting some WCF service in the windows service the right way to go about this and if so, are there any resources on how I would do this?
Thanks!
it seems a reasonable approach to me.
you can get details of how to host a WCF service inside a windows service in the MSDN how to
This code project page also has an example.
you might need to debug start up issues with the service, and I find adding a
Debugger.Launch();
to the beginning of the OnStart method is the easiest way of doing that. it enables you to debug through the start up process of your service and see any exceptions that occur.
I am looking for suggestion for hosting my WCF enterprise application.
The app. require to run without stopping at the server. It also use TCP to yield the best performance at the intranet environment.
I am thinking to host it at window service because IIS recycle process, and has timeout.
However, I find this from the msdn http://msdn.microsoft.com/en-us/library/ff649818.aspx :
Window service...Lack of enterprise features. Windows services do not have the security, manageability, scalability, and administrative features that are included in IIS.
Does it mean Window Service is not suitable for enterprise application? But How about MS SQL, Oracle, MySQL etc. They all host at Win. Service right?
Regards
Bryan
Windows service is suitable for enterprise application! The quoted text actually means that IIS has a lot of built-in management features which are not available in custom hosting (like windows service) unless you implement them at your own.
One of such features is the recycling you want to avoid which helps application to keep low resource consumption (server is in healthy state). Another such feature is IIS checking of the worker state. If worker process looks stuck (don't process requests for any reason), IIS will start automatically another process and routes new requests to that process.
IIS + WAS + AppFabric can provide very big feature set but they are not good for every scenario. If you have service which requires some background continuous, scheduled or multi threaded processing it is probably better to move to self hosted scenario.
We're planning a system running on Windows/.Net 3.5 that has a number of "services" that need to run in the background. Some will be active all of the time, but some will only be called occassionally and can be stood-up on demand.
As far as I can see, my options are:
Windows Services - always running(?)
IIS hosted something - called on demand
COM+/ .Net Enterprise Sevices - most complex option, but most powerful?
Distributed transactions is not a requirement, these are mainly computation engines, rather than transaction processors.
Does anyone have any experience of working with all of these and what further pros & cons can be claimed for each technology?
EDIT
Is suppose there are multiple ways of hosting code in IIS, web services, WCF (as pointed out below), any others? Relative pros/cons?
WCF feels like the right way to go. There are still many choices to make. WCF provides a number of communication mechanisms and hosting environments:
WCF combines the following technologies under one set of APIs-
ASMX;
WSE;
Remoting;
COM+;
MSMQ.
So for instance you can use persistent messages from MSMQ for occassionaly connected clients or standard XML encoding SOAP messages over an HTTP transport layer. You can also use new features in 3.5 like binary encoding of XML or JSON encoding over HTTP.
Hosting environments include:
Console applications
Windows services
WCF services inside IIS 7.0
and on Windows Vista or Windows Server 2008 you can use WAS (Windows Activation Services) to host WCF services.
Different hosting environments have pros and cons. I suggest you look at MSDN for more details (e.g. http://msdn.microsoft.com/en-us/library/bb332338.aspx).
Because WCF encompasses a lot of functionality it is more difficult to learn than any one of the technologies it replaces. I still think it pays for itself in the long run.
It depends on what the software will do, and how (and if) users or systems need to interact with it. Depending on those things, there may be one more, often overlooked, option: set it up as a scheduled task. This is often a very good alternative to a windows service, if the software is of the kind that will act on certain time intervals (check for a change in a database, act on the changed data and send it somewhere, for instance).
If you will have other systems talking directly to your software, I would imagine that a WCF application hosted in IIS would be a rather straighforward way. We use both those approaches in my current assignment; WCF services for looking up and storing data, and scheduled tasks for data calculations that run on a regular basis.
The scheduled task has one upside compared to the others in one specific field; it uses system resources only when running.
You mentioned starting up a process "on demand". WAS - Windows Activation Service, or sometimes called Windows Process Activation Servvice, though it is never abbreviated "WPAS" - is the thing inside Windows that provides on-demand process activation. The way it works - when a message arrives, WAS can start a worker process to handle the message. WAS was, prior to IIS7, fairly tightly integrated into IIS. It was used primarily to activate processes that did web work - like an ASP.NET worker process. With IIS7, WAS is generalized so that it can activate worker processes based on non-HTTP as well as HTTP messages. If you write your app to receive messages through WCF, you can get activation essentially "for free". That applies if it is HTTP, TCP, MSMQ; SOAP or otherwise.
The key thing with this on-demand startup though, is that it is tied to the communication. In fact the process lifecycle model for WAS is tied to communication as well. By default if there are no incoming messages after a while, the process will be shut down by WAS. That may or may not be what you want.
As for process hosting - COM+ offers a hosting environment but it is primarily intended for use as a host for processes that communicate. This may not be the perfect fit for you.
If you have compute engines, you may just want to run a Windows Service. A service like that can be started and stopped either administratively or programmatically. In the latter case, you could imagine a WAS-activated worker process programmatically starting a windows service.
You could also imagine writing a simple Windows Service that watches a location (filesystem, message queue, etc) for a message, and when that file or message arrives, the Windows Service starts up a compute engine process, which itself is NOT a Windows Service, but is just a process.
Speaking of MSMQ - That is basically the same model as MSMQ triggers. You can configure MSMQ to start a process when a message arrives on a particular queue.
There are lots of options.
We have an existing WCF service that makes use of wsDualHttpBinding to enable callbacks to the client. I am considering moving it to netTcpBinding for better performance, but I'm quite wary of moving away from the IIS-hosted service (a "comfort zone" we currently enjoy) into having our own Windows service to host it. I was hoping we could still host this on IIS 7 but Win2K8 won't be reality for us for some time.
What things should I watch out for when creating our own Windows service to host our WCF service? Things like lifetime management and request throttling are features that come free with IIS hosting so I'd also like to know how we can effectively host our service on our own without the convenience of having IIS do the hard work for us. Thanks! :)
So as you cannot host using WAS there are a couple of things to realise.
If the service crashes it doesn't restart by default (although you can change this in service properties)
IIS will recycle the application pool if it hangs or grows too big; you must do this yourself if you want the same sort of reliability.
You must create an account for the service to run under, or use one of the default services. Resit the temptation to run the service as SYSTEM or under an administrator account; if you want to use a built in account use NETWORK SERVICE.
It becomes harder to debug in situ.
Consider using a error logger such as log4net
Having said that I deployed a WCF/Windows service combination for a customer 9 months ago; it's heavily used and hasn't died once.
You can request throttle in a Windows service, it's part of the WCF configuration. Note the defaults are very low, it is likely you will have to increase these.
Hosting in a Windows Service Application (http://msdn.microsoft.com/en-us/library/ms734781.aspx) is a good start.
If you can host your service on Vista, you can also benefit from Windows Process Activation Service (WAS). WAS is a generalization of the IIS process activation, which can be used to activate processes over non-HTTP endpoints (TCP, Named Pipe, MSMQ). To learn more about WCF hosted in WAS, read http://msdn.microsoft.com/en-us/library/ms733109.aspx. To learn how to install and configure WAS, read http://msdn.microsoft.com/en-us/library/ms731053.aspx.