[system][wmi_check] handle TimeoutException

[yannmh]

[core][wmi] list to cache connections

Use a list to cache WMI connections instead of a set.

[system][wmi_check] handle TimeoutException

WMI queries can potentially raise a TimeoutException on query timeouts. Handle it.

[truthbk]

Looks good, just as we had discussed... my only question here is where do we want to call pythoncom.CoInitialize() - one option could be _query(), the other would be in get_connection() - note that I believe that when you call CoInitialize() you must also call Dispatch() and ConnectServer() to get a new live connection. IMHO this should be in get_connection() and let the old connection get garbage collected... otherwise the sampler becomes kind of cumbersome to use.

The thing then would be, it wouldn't make too much sense to cache the connection if in reality we actually create a new one every time we call get_connection().... 😕

Almost certainly connection here will be closed and we'd need to call CoInitialize(), Dispatch(), etc... again