WIP Connection pooler support

Add an initial support for a connection pooler. The idea is to make it
generic enough to be able to switch a corresponding docker image to
change from pgbouncer to e.g. odyssey. Operator needs to create a
deployment with pooler and a service for it to access.

pkg/util/config/config.go

@@ -83,6 +83,16 @@ type LogicalBackup struct {
 	LogicalBackupS3SSE             string `name:"logical_backup_s3_sse" default:"AES256"`
 }
 
+// Operator options for connection pooler
+type ConnectionPool struct {
+	NumberOfInstances *int32 `name:"connection_pool_instances_number" default:"1"`
+	Schema            string `name:"connection_pool_schema" default:"pooler"`
+	User              string `name:"connection_pool_user" default:"pooler"`
+	Type              string `name:"connection_pool_type" default:"pgbouncer"`
+	Image             string `name:"connection_pool_image"  default:"pgbouncer:1.0"`
+	Mode              string `name:"connection_pool_mode"  default:"session"`
+}
+
 // Config describes operator config
 type Config struct {
 	CRD
@@ -90,6 +100,7 @@ type Config struct {
 	Auth
 	Scalyr
 	LogicalBackup
+	ConnectionPool
 
 	WatchedNamespace string            `name:"watched_namespace"`    // special values: "*" means 'watch all namespaces', the empty string "" means 'watch a namespace where operator is deployed to'
 	EtcdHost         string            `name:"etcd_host" default:""` // special values: the empty string "" means Patroni will use K8s as a DCS

pkg/util/constants/roles.go

@@ -2,15 +2,16 @@ package constants
 
 // Roles specific constants
 const (
-	PasswordLength         = 64
-	SuperuserKeyName       = "superuser"
-	ReplicationUserKeyName = "replication"
-	RoleFlagSuperuser      = "SUPERUSER"
-	RoleFlagInherit        = "INHERIT"
-	RoleFlagLogin          = "LOGIN"
-	RoleFlagNoLogin        = "NOLOGIN"
-	RoleFlagCreateRole     = "CREATEROLE"
-	RoleFlagCreateDB       = "CREATEDB"
-	RoleFlagReplication    = "REPLICATION"
-	RoleFlagByPassRLS      = "BYPASSRLS"
+	PasswordLength            = 64
+	SuperuserKeyName          = "superuser"
+	ConnectionPoolUserKeyName = "pooler"
+	ReplicationUserKeyName    = "replication"
+	RoleFlagSuperuser         = "SUPERUSER"
+	RoleFlagInherit           = "INHERIT"
+	RoleFlagLogin             = "LOGIN"
+	RoleFlagNoLogin           = "NOLOGIN"
+	RoleFlagCreateRole        = "CREATEROLE"
+	RoleFlagCreateDB          = "CREATEDB"
+	RoleFlagReplication       = "REPLICATION"
+	RoleFlagByPassRLS         = "BYPASSRLS"
 )

pkg/util/k8sutil/k8sutil.go

@@ -39,6 +39,7 @@ type KubernetesClient struct {
 	corev1.NamespacesGetter
 	corev1.ServiceAccountsGetter
 	appsv1.StatefulSetsGetter
+	appsv1.DeploymentsGetter
 	rbacv1beta1.RoleBindingsGetter
 	policyv1beta1.PodDisruptionBudgetsGetter
 	apiextbeta1.CustomResourceDefinitionsGetter
@@ -101,6 +102,7 @@ func NewFromConfig(cfg *rest.Config) (KubernetesClient, error) {
 	kubeClient.NodesGetter = client.CoreV1()
 	kubeClient.NamespacesGetter = client.CoreV1()
 	kubeClient.StatefulSetsGetter = client.AppsV1()
+	kubeClient.DeploymentsGetter = client.AppsV1()
 	kubeClient.PodDisruptionBudgetsGetter = client.PolicyV1beta1()
 	kubeClient.RESTClient = client.CoreV1().RESTClient()
 	kubeClient.RoleBindingsGetter = client.RbacV1beta1()