Now properly checks if configuration and diagnostics functions are ran in either
main() or in the admin worker. This is useful for debugging and enforcing
thread safety.
Also, monitors are now started and stopped in the admin worker.
By having a separate FINISHED state and a STOPPED state, it is possible to
know at which point in the worker's lifetime an event is done. Posting of
messages before a worker is started is allowed but posting them after the
worker has stopped is not.
This fixes avrorouter related failures and all other failures that stem
from worker messages being ignored at startup.
The command script is now stored in string form. Substitution is performed
using normal string methods instead of regular expressions, since all used
substitutions are simple string replacements. Tokenization is performed after
substitution.
Reactivating monitors shouldn't be done as it's simpler to actually
destroy and create a new one. The performance of reactivation is
insignificant compared to the possible inconsistency problems it allows.
Storing all the runtime errors makes it possible to return all of them
them via the REST API. MaxAdmin will still only show the latest error but
MaxCtrl will now show all errors if more than one error occurs.
The functions are now in MonitorServer. Disk space can only be checked
during specific ticks. If a server misses a tick (e.g. is down) it will
be checked after disk_space_check_interval has passed.
The parameters are now written in the order they appear in the module
parameter definitions. Also enabled a previously disabled part in
server unit test.
Previously, runtime monitor modifications could directly alter monitor fields,
which could leave the text-form parameters and reality out-of-sync. Also,
the configure-function was not called for the entire monitor-object, only the
module-implementation.
Now, all modifications go through the overridden configure-function, which calls the
base-class function. As most configuration changes are given in text-form, this
removes the need for specific setters. The only exceptions are the server add/remove
operations, which must modify the text-form serverlist.
Worker::STOPPED -> MONITOR_STATE_STOPPED
Worker::POLLING -> MONITOR_STATE_RUNNING
Worker::PROCESSING -> MONITOR_STATE_RUNNING
By defining the monitor state from the worker state there is
no risk they will ever get out of sync. And there is one thing
less to maintain.
As m_servers is a member of Monitor, it is better if the closing
of the MYSQL connections is done there, so that derived classes
do not need to remember doing that.
When the servers of a service are defined by a monitor, then
at startup all servers of the monitor should be added to relevant
services. Likewise, when a server is added to or removed from a
monitor at runtime, those changes should affect services as well.
However, whether that should happen or not depends upon the monitor.
In the case of the Clustrix monitor this should not happen as it
adds and removes servers depending on the runtime state of the
Clustrix cluster.
