mysql plugin: Added support for "slave notifications".

The new boolean config option "SlaveNotifications" may be used to enable
notifications if the replication slave I/O and / or SQL threads are not
running (and the respective OKAY notifications). Since this is somewhat
related to the time offset between master and slave, "time_offset" is used for
the type information stored in the notification.

diff --git a/src/mysql.c b/src/mysql.c
index 8f86f4e..565a88e 100644 (file)
--- a/src/mysql.c
+++ b/src/mysql.c
@@ -51,6 +51,10 @@ struct mysql_database_s /* {{{ */
        int   master_stats;
        int   slave_stats;
 
+       int   slave_notif;
+       int   slave_io_running;
+       int   slave_sql_running;
+
        MYSQL *con;
        int    state;
 };
@@ -200,6 +204,10 @@ static int mysql_config (oconfig_item_t *ci) /* {{{ */
        db->socket   = NULL;
        db->con      = NULL;
 
+       /* trigger a notification, if it's not running */
+       db->slave_io_running  = 1;
+       db->slave_sql_running = 1;
+
        plugin_block = 1;
        if (strcasecmp ("Plugin", ci->key) == 0)
        {
@@ -258,6 +266,8 @@ static int mysql_config (oconfig_item_t *ci) /* {{{ */
                        status = mysql_config_set_boolean (&db->master_stats, child);
                else if (strcasecmp ("SlaveStats", child->key) == 0)
                        status = mysql_config_set_boolean (&db->slave_stats, child);
+               else if (strcasecmp ("SlaveNotifications", child->key) == 0)
+                       status = mysql_config_set_boolean (&db->slave_notif, child);
                else
                {
                        WARNING ("mysql plugin: Option `%s' not allowed here.", child->key);
@@ -386,31 +396,30 @@ static MYSQL *getconnection (mysql_database_t *db)
        }
 } /* static MYSQL *getconnection (mysql_database_t *db) */
 
-static void set_host (mysql_database_t *db, value_list_t *vl)
+static void set_host (mysql_database_t *db, char *buf, size_t buflen)
 {
        /* XXX legacy mode - use hostname_g */
        if (db->instance == NULL)
-               sstrncpy (vl->host, hostname_g, sizeof (vl->host));
+               sstrncpy (buf, hostname_g, buflen);
        else
        {
                if ((db->host == NULL)
                                || (strcmp ("", db->host) == 0)
                                || (strcmp ("localhost", db->host) == 0))
-                       sstrncpy (vl->host, hostname_g, sizeof (vl->host));
+                       sstrncpy (buf, hostname_g, buflen);
                else
-                       sstrncpy (vl->host, db->host, sizeof (vl->host));
+                       sstrncpy (buf, db->host, buflen);
        }
 }
 
-static void set_plugin_instance (mysql_database_t *db, value_list_t *vl)
+static void set_plugin_instance (mysql_database_t *db,
+               char *buf, size_t buflen)
 {
        /* XXX legacy mode - no plugin_instance */
        if (db->instance == NULL)
-               sstrncpy (vl->plugin_instance, "",
-                               sizeof (vl->plugin_instance));
+               sstrncpy (buf, "", buflen);
        else
-               sstrncpy (vl->plugin_instance, db->instance,
-                               sizeof (vl->plugin_instance));
+               sstrncpy (buf, db->instance, buflen);
 }
 
 static void submit (const char *type, const char *type_instance,
@@ -421,10 +430,10 @@ static void submit (const char *type, const char *type_instance,
        vl.values     = values;
        vl.values_len = values_len;
 
-       set_host (db, &vl);
+       set_host (db, vl.host, sizeof (vl.host));
 
        sstrncpy (vl.plugin, "mysql", sizeof (vl.plugin));
-       set_plugin_instance (db, &vl);
+       set_plugin_instance (db, vl.plugin_instance, sizeof (vl.plugin_instance));
 
        sstrncpy (vl.type, type, sizeof (vl.type));
        if (type_instance != NULL)
@@ -570,12 +579,11 @@ static int mysql_read_slave_stats (mysql_database_t *db, MYSQL *con)
        /* WTF? libmysqlclient does not seem to provide any means to
         * translate a column name to a column index ... :-/ */
        const int READ_MASTER_LOG_POS_IDX   = 6;
+       const int SLAVE_IO_RUNNING_IDX      = 10;
+       const int SLAVE_SQL_RUNNING_IDX     = 11;
        const int EXEC_MASTER_LOG_POS_IDX   = 21;
        const int SECONDS_BEHIND_MASTER_IDX = 32;
 
-       unsigned long long counter;
-       double gauge;
-
        query = "SHOW SLAVE STATUS";
 
        res = exec_query (con, query);
@@ -598,16 +606,75 @@ static int mysql_read_slave_stats (mysql_database_t *db, MYSQL *con)
                return (-1);
        }
 
-       counter = atoll (row[READ_MASTER_LOG_POS_IDX]);
-       counter_submit ("mysql_log_position", "slave-read", counter, db);
+       if (db->slave_stats)
+       {
+               unsigned long long counter;
+               double gauge;
+
+               counter = atoll (row[READ_MASTER_LOG_POS_IDX]);
+               counter_submit ("mysql_log_position", "slave-read", counter, db);
 
-       counter = atoll (row[EXEC_MASTER_LOG_POS_IDX]);
-       counter_submit ("mysql_log_position", "slave-exec", counter, db);
+               counter = atoll (row[EXEC_MASTER_LOG_POS_IDX]);
+               counter_submit ("mysql_log_position", "slave-exec", counter, db);
 
-       if (row[SECONDS_BEHIND_MASTER_IDX] != NULL)
+               if (row[SECONDS_BEHIND_MASTER_IDX] != NULL)
+               {
+                       gauge = atof (row[SECONDS_BEHIND_MASTER_IDX]);
+                       gauge_submit ("time_offset", NULL, gauge, db);
+               }
+       }
+
+       if (db->slave_notif)
        {
-               gauge = atof (row[SECONDS_BEHIND_MASTER_IDX]);
-               gauge_submit ("time_offset", NULL, gauge, db);
+               notification_t n = { 0, time (NULL), "", "",
+                       "mysql", "", "time_offset", "", NULL };
+
+               char *io, *sql;
+
+               io  = row[SLAVE_IO_RUNNING_IDX];
+               sql = row[SLAVE_SQL_RUNNING_IDX];
+
+               set_host (db, n.host, sizeof (n.host));
+               set_plugin_instance (db,
+                               n.plugin_instance, sizeof (n.plugin_instance));
+
+               if (((io == NULL) || (strcasecmp (io, "yes") != 0))
+                               && (db->slave_io_running))
+               {
+                       n.severity = NOTIF_WARNING;
+                       ssnprintf (n.message, sizeof (n.message),
+                                       "slave I/O thread not started or not connected to master");
+                       plugin_dispatch_notification (&n);
+                       db->slave_io_running = 0;
+               }
+               else if (((io != NULL) && (strcasecmp (io, "yes") == 0))
+                               && (! db->slave_io_running))
+               {
+                       n.severity = NOTIF_OKAY;
+                       ssnprintf (n.message, sizeof (n.message),
+                                       "slave I/O thread started and connected to master");
+                       plugin_dispatch_notification (&n);
+                       db->slave_io_running = 1;
+               }
+
+               if (((sql == NULL) || (strcasecmp (sql, "yes") != 0))
+                               && (db->slave_sql_running))
+               {
+                       n.severity = NOTIF_WARNING;
+                       ssnprintf (n.message, sizeof (n.message),
+                                       "slave SQL thread not started");
+                       plugin_dispatch_notification (&n);
+                       db->slave_sql_running = 0;
+               }
+               else if (((sql != NULL) && (strcasecmp (sql, "yes") == 0))
+                               && (! db->slave_sql_running))
+               {
+                       n.severity = NOTIF_OKAY;
+                       ssnprintf (n.message, sizeof (n.message),
+                                       "slave SQL thread started");
+                       plugin_dispatch_notification (&n);
+                       db->slave_sql_running = 0;
+               }
        }
 
        row = mysql_fetch_row (res);
@@ -738,7 +805,7 @@ static int mysql_read (user_data_t *ud)
        if (db->master_stats)
                mysql_read_master_stats (db, con);
 
-       if (db->slave_stats)
+       if ((db->slave_stats) || (db->slave_notif))
                mysql_read_slave_stats (db, con);
 
        return (0);