extractor will never run

[robkooper]

if the resource or the host is not correctly computed, the extractor will never start, but also not ack the messages, resulting in the extractor being stuck.

See the following places:

pyclowder/pyclowder/connectors.py

Line 381 in b852c63

logging.error("Host is empty, this is bad.")

pyclowder/pyclowder/connectors.py

Line 389 in b852c63

logging.error("No resource found, this is bad.")

In this case all we can do is move the message to the error queue and ack it. It is not possible to send an update to clowder.

[max-zilla]

Started an implementation of this here:
https://github.com/clowder-framework/pyclowder/compare/fail-gracefully-on-bad-resources

Haven't tested it yet but tried to make it generically adaptable for other connectors as well.

[robkooper]

@max-zilla looks good sofar, next comes testing.