Keep mysql readonly after exit group unintentionally (oracle#261)

Since mysql version >= 8.0.12, <= 8.0.15 changed default behavior
to `ABORT_SERVER`. Which will shutdown the server after exit group
unintentionally. It should better change server to `READ_ONLY` instead
of exit.

Future version MySQL also change this behavior back to `READ_ONLY`
https://dev.mysql.com/doc/refman/8.0/en/group-replication-options.html#sysvar_group_replication_exit_state_action

Signed-off-by: Alan Tang <alantang888@gmail.com>

Author: alantang888

pkg/resources/statefulsets/statefulset.go

@@ -33,6 +33,8 @@ import (
 	operatoropts "github.com/oracle/mysql-operator/pkg/options/operator"
 	"github.com/oracle/mysql-operator/pkg/resources/secrets"
 	"github.com/oracle/mysql-operator/pkg/version"
+
+	"github.com/coreos/go-semver/semver"
 )
 
 const (
@@ -48,6 +50,8 @@ const (
 	mySQLSSLVolumeName    = "mysqlsslvolume"
 
 	replicationGroupPort = 13306
+
+	minMysqlVersionWithGroupExitStateArgs = "8.0.12"
 )
 
 func volumeMounts(cluster *v1alpha1.Cluster) []v1.VolumeMount {
@@ -155,6 +159,26 @@ func getReplicationGroupSeeds(name string, members int) string {
 	return strings.Join(seeds, ",")
 }
 
+func checkSupportGroupExitStateArgs(deployingVersion string) (supportedVer bool) {
+	defer func() {
+		if r := recover(); r != nil {
+
+		}
+	}()
+
+	supportedVer = false
+
+	ver := semver.New(deployingVersion)
+	minVer := semver.New(minMysqlVersionWithGroupExitStateArgs)
+
+	if ver.LessThan(*minVer) {
+		return
+	}
+
+	supportedVer = true
+	return
+}
+
 // Builds the MySQL operator container for a cluster.
 // The 'mysqlImage' parameter is the image name of the mysql server to use with
 // no version information.. e.g. 'mysql/mysql-server'
@@ -184,6 +208,10 @@ func mysqlServerContainer(cluster *v1alpha1.Cluster, mysqlServerImage string, ro
 			"--ssl-key=/etc/ssl/mysql/tls.key")
 	}
 
+	if checkSupportGroupExitStateArgs(cluster.Spec.Version) {
+		args = append(args, "--loose-group-replication-exit-state-action=READ_ONLY")
+	}
+
 	entryPointArgs := strings.Join(args, " ")
 
 	cmd := fmt.Sprintf(`

pkg/resources/statefulsets/statefulset_test.go

@@ -323,3 +323,37 @@ func TestClusterDefaultOverride(t *testing.T) {
 
 	assert.Equal(t, "OverrideDefaultImage:"+v1alpha1.DefaultVersion, si)
 }
+
+func TestClusterSetGroupExitStateArgs(t *testing.T) {
+	cluster := &v1alpha1.Cluster{}
+	cluster.EnsureDefaults()
+	cluster.Spec.Version = "8.0.12"
+
+	statefulSet := NewForCluster(cluster, mockOperatorConfig().Images, "mycluster")
+
+	cmd := statefulSet.Spec.Template.Spec.Containers[0].Command[2]
+
+	assert.Contains(t, cmd, "--loose-group-replication-exit-state-action=READ_ONLY")
+
+	cluster2 := &v1alpha1.Cluster{}
+	cluster2.EnsureDefaults()
+	cluster2.Spec.Version = "8.0.13"
+
+	statefulSet2 := NewForCluster(cluster2, mockOperatorConfig().Images, "mycluster")
+
+	cmd2 := statefulSet2.Spec.Template.Spec.Containers[0].Command[2]
+
+	assert.Contains(t, cmd2, "--loose-group-replication-exit-state-action=READ_ONLY")
+}
+
+func TestClusterNotSetGroupExitStateArgs(t *testing.T) {
+	cluster := &v1alpha1.Cluster{}
+	cluster.EnsureDefaults()
+	cluster.Spec.Version = "8.0.11"
+
+	statefulSet := NewForCluster(cluster, mockOperatorConfig().Images, "mycluster")
+
+	cmd := statefulSet.Spec.Template.Spec.Containers[0].Command[2]
+
+	assert.NotContains(t, cmd, "--loose-group-replication-exit-state-action=READ_ONLY")
+}