WCF Web服务监视其他WCF Web服务

Question

I would like to have a Traffic COP or Controller WCF Web Service that doesn't do anything with data but instead gives orders to another WCF Web Service to do so.

Could someone give me an example of how this might be able to be done. It would be preferable that I was not getting into any APM stuff. Instead just an observer who later gets to spin another one way contract to a WCF Web Service when it needs to after it sees that there are no more other WCF Web Services with the same meta data in memory or processing currently.

If this is impossible please say so. Unless you know a small example of how it is done. Maybe a pointer where somebody has already covered the topic?

Thanks apolfj

Answer 1

I don't really understand your question, but maybe this will help:

• MSE is a "service virtualization" approach
• Stocktrader has a WCF load balancer included in it.

Maybe one of them will fit your needs.

Answer 2

Having a 'traffic cop' service that all traffic goes through before it gets to the actual web service for processing will add extra overhead to your solution. Then you also have issues like once you've logged a call going to a particular web service, how do you find out if the response was successful? Then you hvae to do more logging of some sort and finally return the result to the client. If I understand what you were saying correctly (which I'm not entirely sure I do) you would be looking at something like;

Client -> TrafficCop -> Service1
Client -> TrafficCop -> Service2

OR

Client -> Service1 -> TrafficCop

...depending on where you want the entry point and what you need to do.

I would probably remove the traffic cop web service entirely and implement some API's for your service to implement and have each web service log some information before a service operation is called and after the operation has completed. I'd recommend you take a look at this link; http://msdn.microsoft.com/en-us/magazine/cc163302.aspx which covers behaviours, operation invokers and paramter inspectors.

This way each web service can log information, check access, rules, report errors before and after execution to a database or another TrafficCop web service if you really want. But I'd probably be inclined to just stick all that information in its own database. Thus each web service (depending on what you're doing) may have connections to two databases. One for the web service itself (if that's needed) and one to the TrafficCop / logging database.

At a later date you then may choose to add a website that pulls all the information out of the traffic cop database and allows you to easily browse / search it. It could highlight warnings or other issues your web services logged.

Summary

If all you need to do is logging and related functionality I would consider having each web service log and / or check rules and other things before and / or after a service operation is invoked. At a later date you could consider adding an admin site that surfaces all this information so you can easily keep an eye on how your web services are performing. You may even like to log information like how long it takes to respond to certain requests.

If this is not what you are after I would suggest you add more information and continue to keep your original question up to date.