Treat fanout (client) subscriptions as a no-op

[cwjohnston]

As documented in issue #5, clients with subscriptions defined encounter
exceptions when they attempt to process check results as check requests.

With Sensu's forthcoming native silencing implementation, each client
definition will include a subscription for "client:$CLIENT_NAME". For the
purposes of this silencing implemetation, it's not important that the client
consume check requests from this subscription, but it is important that the
subscription is present in the client definition sent via keepalive messages.

When Sensu processes call subscribe() on the transport object, they pass a
queue type. Sensu server processes subscribe with type :direct while
Sensu client processes use type :fanout. This distinction makes it possible
for us to treat client subscriptions for this transport as a no-op.

[cwjohnston]

/cc @runningman84 and @troyready due to interest registered on sensu/sensu-settings#40

[runningman84]

@cwjohnston thanks for your help here! How can I use you updated file without waiting for a gem update? Where does sensu look for files? I think about putting the snssqs.rb file using chef somewhere in the filesystem until this get released.

[troyready]

@runningman84 clone cwjohnston's fork of the gem source (specifically the branch with the fix in it), build it, and install it with the sensu_gem sensu cookbook resource.

You could just use Chef to override this one file -- a little too hacky but admittedly nice in simplicity, e.g.:

# Place updated snssqs.rb in templates folder as snssqs.rb.erb
# Update snssqs_transport_lib path per your sensu install
  snssqs_transport_lib = 'C:\opt\sensu\embedded\lib\ruby\gems\2.0.0\gems\\'\
                         'sensu-transport-snssqs-2.0.2\lib\sensu\transport\\'\
                         'snssqs.rb'
  template snssqs_transport_lib

[tomwans]

Looks good. Thanks all for looking out for our little transport :)

btw that chef hack is nice.