GitLab

Fix all PEP8 errors but E221 (multiple spaces before operator).

This eases renaming of the module, and helps the uneducated reader
locate the source of the import.

Omitting addresses in Host instanciation now defaults to doc-reserved
IP addresses, so that one can create hosts that are not dual-stacked.

This implementation uses smtplib so that mails are sent via SMTP, even
when the mail daemon could be local, to be as flexible as possible.

Users may configure a name string for hosts, and checks can have a
named option that will be used as target name (useful for mails).
Hosts' name default to "ipv4/ipv6" and checks' to "Unknown" as they
may apply to any kind of things (like hosts of course but also zones, …)

This uses nagios' /usr/lib/nagios/plugins/check_http as packaged
within Debian.

"every" is a loop, meaning that it always has to rotate back to
the begining when the threshold is met. But retry is more like a
ceiling, menaning that after the threshold it is "too much".
So modulo is perfect for "every" and for "retry", use min().

Move workaround for Python bug http://bugs.python.org/issue18851 to
lib/subprocess_compat.py.

Don't show empty outputs and decode bytes (so that things like newlines
are printed as such and not as litteral "\n").

The CheckDNSZone implementation now calls the check available here:
https://github.com/bortzmeyer/check_dns_soa

Handle OSError exceptions (such as non-existing command) for the
Popen command spawning.
Surround that by a mutex as Popen is not atomic when failing!

Create a directory "lib/", put the checks there. Move the compat file
there too.
Also put the config in a separate file so that users may edit without
messing up the core. Would also ease intallation so that config
may land in etc/ for example.

Apparently, Popen.args is new and undocumented in Python 3.3, so don't
rely on its existence and set it ourselves.

Now the granularity is the check level, allowing to write checks
without hosts. Checks don't deal with hosts anymore.
Also the results of checks are now handled outside of the checking
path, but this may change when the infinite loop and time intervals
are going to be implemented.

IPy is only used to get the version of an IP (4 or 6), but the IPs come
from reasonably trustable sources and if incorrect would at worse make
the test fail -- which is valid behavior.

So, no need for a real library to distinguish them, do a naive check
based on the presence of version-specific delimiters.