enableMgrAlert:Return different values according to different states of performance_schema.replication_group_members column member_state state, and then alarm for MGR. Performance_schema. replication_group_members MEMBER_STATE: returns 0 when not ONLINE. Configure rules in Prometheus for sending MGR non-online alarm.

Signed-off-by: jianshenghan <[email protected]>

Author: SuperQ

Diff for: README.md

@@ -106,6 +106,7 @@ config.my-cnf                              | Path to .my.cnf file to read MySQL
 log.level                                  | Logging verbosity (default: info)
 exporter.lock_wait_timeout                 | Set a lock_wait_timeout (in seconds) on the connection to avoid long metadata locking. (default: 2)
 exporter.log_slow_filter                   | Add a log_slow_filter to avoid slow query logging of scrapes.  NOTE: Not supported by Oracle MySQL.
+tls.insecure-skip-verify                   | Ignore tls verification errors.
 web.config.file                            | Path to a [web configuration file](#tls-and-basic-authentication)
 web.listen-address                         | Address to listen on for web interface and telemetry.
 web.telemetry-path                         | Path under which to expose metrics.

Diff for: collector/perf_schema_replication_group_members.go

@@ -60,7 +60,7 @@ func (ScrapePerfReplicationGroupMembers) Scrape(ctx context.Context, db *sql.DB,
 	for i := range scanArgs {
 		scanArgs[i] = &sql.RawBytes{}
 	}
-
+	memberStateValue := float64(0)
 	for perfReplicationGroupMembersRows.Next() {
 		if err := perfReplicationGroupMembersRows.Scan(scanArgs...); err != nil {
 			return err
@@ -71,6 +71,9 @@ func (ScrapePerfReplicationGroupMembers) Scrape(ctx context.Context, db *sql.DB,
 		for i, columnName := range columnNames {
 			labelNames[i] = strings.ToLower(columnName)
 			values[i] = string(*scanArgs[i].(*sql.RawBytes))
+			if labelNames[i] == "member_state" && values[i] == "ONLINE" {
+				memberStateValue = 1
+			}
 		}
 
 		var performanceSchemaReplicationGroupMembersMemberDesc = prometheus.NewDesc(
@@ -82,7 +85,7 @@ func (ScrapePerfReplicationGroupMembers) Scrape(ctx context.Context, db *sql.DB,
 		)
 
 		ch <- prometheus.MustNewConstMetric(performanceSchemaReplicationGroupMembersMemberDesc,
-			prometheus.GaugeValue, 1, values...)
+			prometheus.GaugeValue, memberStateValue, values...)
 	}
 	return nil