get_superuser_connection() was erroneously using the local node record
to connect to as a superuser, which works when registering the primary
but obviously not when cloning a standby.
Addresses GitHub #380.
If repmgrd is running in degraded mode on a primary which has been stopped,
then manually been brought back online as a standby (e.g. by creating
recovery.conf and starting the server), ensure it not only detects the
change but automatically updates the node record so it can resume
monitoring the node as a standby.
Previously, repmgrd was looping waiting for the record to be updated
(as is done transparently when executing "repmgr node rejoin") but
if the record was not updated within the timeout period (e.g. by
"repmgr standby register) it would fail to resume monitoring as a
standby.
It seems reasonable to have repmgrd automatically update the node record,
as this will restore failover capability as quickly as possible. If this
is not desired, then the onus is on the user to shut down repmgrd while
making the desired changes.
Check that sufficient walsenders will be available on the promotion
candidate, and if replication slots are in use check if enough of
those will be available.
Note these checks can't guarantee that the walsenders/slots will
be available at the appropriate points during the switchover process,
but do ensure that existing configuration problems will be caught.
Implements GitHub #371.
In particular, if running "repmgr cluster show" against a database
without the repmgr metadata, showing the error (rather than just
"no records found" etc.) will provide some clues about the problem.
Previously, if an issue was encountered with the old primary, but user
provided -F/--force to have repmgr promote the standby anyway, repmgr
would exit with the log message "STANDBY SWITCHOVER is complete"
and exit code 0 (SUCCESS).
To better report this partial completion, repmgr will now emit the message
"STANDBY SWITCHOVER has completed with issues" (and a HINT to check preceding
log messages) and new exit code 22 (ERR_SWITCHOVER_INCOMPLETE).
