The default value set by the module was a value of None for the
config_file parameter, which propogates into the connect method
call overriding the stated default in the method.
Instead, the default should be set with-in the parameter
specification so the file check is not requested to check None.
Docs imply the mysql_variables is used to operate a single variable therefore
- fail before making any db connections if variable is not set
- validate chars for mysql variable name with re.match(^[a-z0-9_]+)
- use "SHOW VARIABLE WHERE Variable_name" instead of LIKE search
- getvariable() returns only the value or None if variable is not found
- the module returns only the found variable value instead of tuple for easier operation eg. as registere variable in tasks
Ports are integer values but the old code was assuming they were
strings. When login_port is put into playbook complex_args as an
integer the code would fail. This update should make the argument
validating make sure we have an integer and then we can send that value
directly to the relevant APIs.
Fixes#818