All global parameters are now handled by the runtime configuration
modification code. The parameters that are trivial to update can now be
updated at runtime. All other global parameters cause a new error message
to be returned stating that the parameter in question cannot be modified
at runtime.
Also updated the list of modifiable parameters in MaxCtrl. This list
should not be stored in MaxCtrl and should be created by MaxScale at
runtime.
When a listener was created at runtime but it failed to start, it would
not be automatically removed from the system. This caused the MaxCtrl
cluster sync test to fail.
Replaced the DCB with a single file descriptor that the listener listens
on and which is added to all of the workers. The Listener also extends the
MXB_POLL_DATA which allows it to handle epoll events.
Moved the code that creates the listening socket into listener.cc where it
belongs and did a minor cleanup of it.
By storing the reference in the DCB, the two-way dependency between the
listeners and services is severed. Now the services have no direct link to
listeners and after the destruction of a listener it will be freed once
all connections through it have closed.
Due to the fact that a listener itself has a DCB that must point to a
valid listener, a self-reference is stored in the listener DCB. This is
extremely confusing and is only here to keep the code functional until the
DCB part of the listener can be factored out.
By storing a shared pointer to the listeners in the services, they will be
available as long as the service using them exists. This enables clean
destruction of listeners that still have open sessions.
The listener creation code now separately creates the listener and links
it to the service. Also replaced relevant parts of the related code with
the listener implemented versions of it.
This is currently disallowed for the server parameter, as the value could be
read/written concurrently. The monitor parameter can be changed since the
monitor is stopped during write.
If a listener is defined in a static configuration file, it can now be
destroyed at runtime. If MaxScale is restarted, the listener will be
created again unless the configuration file is modified.
See script directory for method. The script to run in the top level
MaxScale directory is called maxscale-uncrustify.sh, which uses
another script, list-src, from the same directory (so you need to set
your PATH). The uncrustify version was 0.66.
The monitor JSON is now more closely inspected before the actual monitor
is allocated. This prevents creation of monitors without credentials which
was previously possible.
The monitor alteration was also changed to stop and start the monitor only
once instead of stopping and starting after each parameter
modification. This prevents multi-parameter updates from failing due to
monitors seeing a partial set of the new values. Currently only the
`replication_user` and `replication_password` parameters could cause this.
If a service was created at runtime, it would be in the Allocated state
until it was stopped. The serviceStart function isn't necessary from a
functional point of view (a new service cannot have listeners that need
starting) but it does set the correct state and it's the "right" thing to
do.
Monitors created via the REST API that were started and configured
successfully should also be started. This removes the extra step of
starting the monitor after creating it.
The parameter validation for all module types follows roughly the same
path: first check whether it's a known parameter and then whether the
value is valid. This can be moved into common functions that removes
duplicated code.
The SSL initialization should only be attempted if `ssl_key`, `ssl_cert`
or `ssl_ca_cert` is defined. In addition to this, the SSL parameters
requirements for servers and listeners are different: servers require only
`ssl_ca_cert` but listeners require all three.
The runtime modification of servers, services and monitors now validates
the parameters before starting the update process. This guarantees that
the set of parameters is valid before it is processed.
After the validation, the parameters are now also stored in the list of
configuration parameters. This will simplify the serialization process by
removing the need to explicitly serialize all common object parameters.
If a module is not found, a proper error message is now given to the
user. Other system errors are also printed if errno is set. Dynamic
library errors aren't printed as they are apparently reset after a call to
`dlerror`, at least according to documentation.
Took the size type validity check function into use in runtime
configuration. This fixes the problem with zero not being accepted as a
valid size for query_classifier_cache_size.
