Validation for pgBackRest Data Sources

Adds validation to ensure only cloud-based repos (S3, Azure or GCS) are
configured as a pgBackRest data source.

Author: andrewlecuyer

config/crd/bases/postgres-operator.crunchydata.com_postgresclusters.yaml

@@ -6519,6 +6519,11 @@ spec:
                     - repo
                     - stanza
                     type: object
+                    x-kubernetes-validations:
+                    - fieldPath: .repo
+                      message: Only S3, GCS or Azure repos can be used as a pgBackRest
+                        data source.
+                      rule: '!has(self.repo.volume)'
                   postgresCluster:
                     description: |-
                       Defines a pgBackRest data source that can be used to pre-populate the PostgreSQL data

pkg/apis/postgres-operator.crunchydata.com/v1beta1/postgrescluster_types.go

@@ -194,6 +194,7 @@ type DataSource struct {
 	// The PGBackRest field is incompatible with the PostgresCluster field: only one
 	// data source can be used for pre-populating a new PostgreSQL cluster
 	// +optional
+	// +kubebuilder:validation:XValidation:rule="!has(self.repo.volume)", message="Only S3, GCS or Azure repos can be used as a pgBackRest data source.", fieldPath=".repo"
 	PGBackRest *PGBackRestDataSource `json:"pgbackrest,omitempty"`
 
 	// Defines a pgBackRest data source that can be used to pre-populate the PostgreSQL data