Moved some typedefs to router.h and server.h, changed a few
constants to these enums. Renamed some types in config.h to
remove "Gateway".
There are still some functions in the public header which are
only used in core, but they seem to fit the theme of public functions
so were not moved.
All modules now declare a name for the module. This is name is added as a
prefix to all messages logged by a module. The prefix should help
determine which part of the system logs a message.
This removes parts of the nearly identical code from all monitors.
The removal of monitor type specific event checking is done based on the
assumption that only the monitor that is monitoring the server can be the
cause for a state change. This removes the need to actually check that the
state change is relevant for each monitor and allows the event handling to
be moved into the core.
The MXS_MODULDE object now contains optinal pointers for functions
to be called att process and thread startup and shutdown. Since the
functions were added to the end, strictly speaking, all structures
would not have needed to have been modified, but better to be
explicit. In a subsequent change, these will be called.
C++ does not support flexible arrays, so for the time being C++
modules are restricted to 10 parameters. Better approach is to
factor out the parameters to a separate array and then just store
a pointer to that array in MXS_MODULE.
All monitors now declare the parameters that they use. This allows the
core to check the validity of the parameters before they are passed to the
monitor. It also simplifies the processing of the parameters as they are
guaranteed to be valid.
The MODULE_INFO is now the main object which is used by modules to convey
information to the MaxScale core. The MXS_MODULE name is more apt as it
now contains the actual module definition.
The old MODULES structure was moved into load_utils.c as an internal
implementation and was renamed so that it is not confused with the new
MODULE structure.
The modules are now declared with a common macro. This allows future
additions to the module loading process while also making the loaded
symbol name a constant.
This allows modules to only expose one entry point with a consistent
signature. In the future, this could be used to implement declarations of
module parameters.
Previously, server status changes from MaxAdmin would be set immediately
as long as the server lock could be acquired. This meant that it might take
several seconds until the next monitor pass is executed. Usually, this was
fine but in some situations we would want the monitor to run immediately
after the change (MXS-740 and Galera). This patch changes the logic of
setting and clearing status bits to a delayed mode: changes are first applied
to a "status_pending"-variable, and only once the monitor runs will the
setting be applied. To reduce the delay, the monitor now has a flag
which is checked during sleep (between short 0.1s naps). If set, the
sleep is cut short.
If a server is not monitored, the status bits are set directly.
There is a small possibility of a race condition: If a monitor is stopped or
destroyed before the pending change is applied, the change is forgotten.
MXS-873 To prevent monitors and MaxAdmin from interfering with each other,
changes to the server status flags now happen under a lock. To avoid
interfering with monitor logic, the monitors now acquire locks to all
of their servers at the start of the monitor loop and release them
before sleeping.
Each monitor module now resides in a subdirectory of its own.
The name of the subdirectory is the same as the name of the
library in the module's CMakeLists.txt file.
