From COM+ to WCF

[Remote_User]

Hi,
If I have my COM+ component which gets loaded from a service
(loaded in IIS for example) and if that component crashes it is
limited only to that component. The service as such is fine except
that the calls for the crashed components are gone. Now, if I have a
WCF service again hosted in IIS which loads a .NET component and
suppose if that component crashes, is my service gone? For testing if
I don't handle an exception and actually give an input which generates
that situation will my service go down?

Have I missed something or is this the drawback for this kind of
approach?

Thanks.

 

[Marc Gravell]

Now, if I have a

WCF service again hosted in IIS which loads a .NET component and
suppose if that component crashes, is my service gone?

Typically, it just means that the affected request(s) will return a
fault exception. But you'd need to be more specific...

Marc

 

[Remote_User]

Typically, it just means that the affected request(s) will return a
fault exception. But you'd need to be more specific...

Marc

Marc, Thanks for the reply.
My question will be, if the same service is responsible to load other
components based on the client input requests, then will one component
crashing cause the service to get crashed since the component gets
loaded in the service address space? Will each component be a single
point of failure?

 

[Marc Gravell]

I'm sorry, but that depends entirely on how you code it! What exactly
is failing? A single failed request won't normally corrupt an entire
app, unless you simply code it badly...
To answer this question sensibly you would need to describe what type
of bizarre crash you are expecting, and what you are defining as a
"component" (in your "will each component be...").

Marc

 

[Remote_User]

I'm sorry, but that depends entirely on how you code it! What exactly
is failing? A single failed request won't normally corrupt an entire
app, unless you simply code it badly...
To answer this question sensibly you would need to describe what type
of bizarre crash you are expecting, and what you are defining as a
"component" (in your "will each component be...").

Marc

Okay so I have my WCF service which based on the input will load any
of the component. Here component will be just another dll developed
in .NET.
For testing purposes I can generate a FileNotFound exception and let
it go unhandled. So in that case will the service be able to still
accept and route other incoming requests?

Thanks.

 

[Marc Gravell]

Yes.

Don't get me wrong; it is perfectly possible to shaft an AppDomain,
but it won't happen just because you throw an exception. Exceptions
are anticipated.

(please: no purist "exceptions are *never* expected" wars...)

Marc

 

[Marc Gravell]

One caveat; it will probably trash the proxy (and session). Once your
client proxy has received a fault, you should really ditch it. But the
WCF service itself is still good to go...

Marc

 

[Remote_User]

One caveat; it will probably trash the proxy (and session). Once your
client proxy has received a fault, you should really ditch it. But the
WCF service itself is still good to go...

Marc

Thanks for the comments
But it will be over http and we are not maintaining states though ..
Hopefully my service remains just fine !