This allows us not to enable the inotify handler immediately, and thus
to make it easier for us should the config file not exist at all.

Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>

This is a state the processor will get in, if it fails to load the
config.

Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>

This will be useful to make ConfdProcessor aware of a config failure,
without quitting confd.

Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>

In a case we don't encounter frequently (file modified but not
overwritten) the notify handler we use is called with a wrong name.

Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>

Timers are used both for checking for inotify failures, and for polling,
should inotify notices become too frequent.

Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>

Rather than raising ConfdFatalError directly
ConfdInotifyEventHandler.enable raises InotifyError should it not be
able to configure inotify, allowing the caller to decide what to do.

Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>

ConfdInotifyEventHandler used to reload the config whenever a
notification arrived. Moving to a callback system, so that
ConfdConfigurationReloader can be responsible for that functionality.

Additionally the inotify class no longer reenables itself automatically,
but just notifies the callback if it's been disabled, and waits for its
call to enable(). This allows, should ConfdConfigurationReloader decide
it wants to move to polling, to avoid having a double enable()/disable()
call.

Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>

This class will be responsible for managing inotify notifications,
timers, and rate-limiting reloads. For now none of these features is
implemented. :)

Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>

Make possible to enable and disable the inotify event handler.  The
inotify handler will remain enabled, unless explicitely told to disable
itself.

Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>

Signed-off-by: Michael Hanselmann <hansmi@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>

Now that mainloop is asyncore-enabled we can easily do that.

Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>

confd.server and daemons/ganeti-confd import a few modules they don't
actually use. Clean them up.

Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>

ganeti-confd is a simple asynchronous daemon, which listens on a UDP
port, passes each packet to a processor, and sends back to the client
the result.

It also listens on an inotify socket, in order to reload its
configuration when the ganeti config file changes.

Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>