Improve log management (#27)

* New log management (see #25)

- Add logrotate (as optional feature) setup
- Delete obsolete log management (log + log_slow_queries)

* Change log path

templates/etc/logrotate.d/mysql-server.j2

@@ -0,0 +1,24 @@
+#
+# {{ ansible_managed }}
+#
+
+# - I put everything in one block and added sharedscripts, so that mysql gets
+#   flush-logs'd only once.
+#   Else the binary logs would automatically increase by n times every day.
+# - The error log is obsolete, messages go to syslog now.
+{{ mysql_log_error }} {% if mysql_slow_query_log_enabled %}{{ mysql_slow_query_log_file }}{% endif %} {
+	daily
+	rotate 7
+	missingok
+	create 640 mysql adm
+	compress
+	sharedscripts
+	postrotate
+          test -x /usr/bin/mysqladmin || exit 0
+          if [ -f `my_print_defaults --mysqld | grep -m 1 -oP "pid-file=\K.+$"` ]; then
+            # If this fails, check debian.conf!
+            mysqladmin --defaults-file=/etc/mysql/debian.cnf --local flush-error-log \
+              flush-engine-log flush-general-log flush-slow-log
+          fi
+	endscript
+}

templates/etc/mysql/my.cnf.j2

@@ -14,21 +14,15 @@ socket = {{ mysql_socket }}
 
 {# TODO: FIX later #}
 # Logging configuration.
-{% if mysql_log_error == 'syslog' or mysql_log == 'syslog' %}
+{% if mysql_log_error == 'syslog' %}
 syslog
 syslog-tag = {{ mysql_syslog_tag }}
 {% else %}
-{% if mysql_log %}
-log = {{ mysql_log }}
-{% endif %}
 log-error = {{ mysql_log_error }}
 {% endif %}
 
 {% if mysql_slow_query_log_enabled %}
 # Slow query log configuration.
-{% if mysql_vendor not in ['mariadb', 'mariadbgalera'] or mysql_mariadb_version | version_compare('10.0', '<') %}
-log_slow_queries = 1
-{% endif %}
 slow_query_log = 1
 slow_query_log_file = {{ mysql_slow_query_log_file }}
 long_query_time = {{ mysql_slow_query_time }}