feat: Add SubPathExpr option for additionalVolumes

Author: smutel

charts/postgres-operator/crds/postgresqls.yaml

@@ -101,6 +101,8 @@ spec:
                       x-kubernetes-preserve-unknown-fields: true
                     subPath:
                       type: string
+                    isSubPathExpr:
+                      type: boolean
               allowedSourceRanges:
                 type: array
                 nullable: true

docs/reference/cluster_manifest.md

@@ -227,6 +227,7 @@ These parameters are grouped directly under  the `spec` key in the manifest.
   It allows you to mount existing PersistentVolumeClaims, ConfigMaps and Secrets inside the StatefulSet.
   Also an `emptyDir` volume can be shared between initContainer and statefulSet.
   Additionaly, you can provide a `SubPath` for volume mount (a file in a configMap source volume, for example).
+  Set `isSubPathExpr` to true if you want to include [API environment variables](https://kubernetes.io/docs/concepts/storage/volumes/#using-subpath-expanded-environment).
   You can also specify in which container the additional Volumes will be mounted with the `targetContainers` array option.
   If `targetContainers` is empty, additional volumes will be mounted only in the `postgres` container.
   If you set the `all` special item, it will be mounted in all containers (postgres + sidecars).

manifests/complete-postgres-manifest.yaml

@@ -81,6 +81,16 @@ spec:
 #        PersistentVolumeClaim:
 #          claimName: pvc-postgresql-data-partitions
 #          readyOnly: false
+#    - name: data
+#      mountPath: /home/postgres/pgdata/partitions
+#      subPath: $(NODE_NAME)/$(POD_NAME)
+#      isSubPathExpr: true
+#      targetContainers:
+#        - postgres
+#      volumeSource:
+#        PersistentVolumeClaim:
+#          claimName: pvc-postgresql-data-partitions
+#          readyOnly: false
 #    - name: conf
 #      mountPath: /etc/telegraf
 #      subPath: telegraf.conf

manifests/postgresql.crd.yaml

@@ -99,6 +99,8 @@ spec:
                       x-kubernetes-preserve-unknown-fields: true
                     subPath:
                       type: string
+                    isSubPathExpr:
+                      type: boolean
               allowedSourceRanges:
                 type: array
                 nullable: true

pkg/apis/acid.zalan.do/v1/crds.go

@@ -167,6 +167,9 @@ var PostgresCRDResourceValidation = apiextv1.CustomResourceValidation{
 									"subPath": {
 										Type: "string",
 									},
+									"isSubPathExpr": {
+										Type: "boolean",
+									},
 								},
 							},
 						},

pkg/apis/acid.zalan.do/v1/postgresql_type.go

@@ -141,6 +141,7 @@ type AdditionalVolume struct {
 	Name             string          `json:"name"`
 	MountPath        string          `json:"mountPath"`
 	SubPath          string          `json:"subPath,omitempty"`
+	IsSubPathExpr    bool            `json:"isSubPathExpr,omitemtpy"`
 	TargetContainers []string        `json:"targetContainers"`
 	VolumeSource     v1.VolumeSource `json:"volumeSource"`
 }

pkg/cluster/k8sres.go

@@ -1751,11 +1751,18 @@ func (c *Cluster) addAdditionalVolumes(podSpec *v1.PodSpec,
 		for _, additionalVolume := range additionalVolumes {
 			for _, target := range additionalVolume.TargetContainers {
 				if podSpec.Containers[i].Name == target || target == "all" {
-					mounts = append(mounts, v1.VolumeMount{
+					v := v1.VolumeMount{
 						Name:      additionalVolume.Name,
 						MountPath: additionalVolume.MountPath,
-						SubPath:   additionalVolume.SubPath,
-					})
+					}
+
+					if additionalVolume.IsSubPathExpr {
+						v.SubPathExpr = additionalVolume.SubPath
+					} else {
+						v.SubPath = additionalVolume.SubPath
+					}
+
+					mounts = append(mounts, v)
 				}
 			}
 		}

pkg/cluster/k8sres_test.go

@@ -1812,6 +1812,25 @@ func TestAdditionalVolume(t *testing.T) {
 				EmptyDir: &v1.EmptyDirVolumeSource{},
 			},
 		},
+		{
+			Name:             "test5",
+			MountPath:        "/test5",
+			SubPath:          "/test5",
+			TargetContainers: nil, // should mount only to postgres
+			VolumeSource: v1.VolumeSource{
+				EmptyDir: &v1.EmptyDirVolumeSource{},
+			},
+		},
+		{
+			Name:             "test6",
+			MountPath:        "/test6",
+			SubPath:          "$(POD_NAME)",
+			IsSubPathExpr:    true,
+			TargetContainers: nil, // should mount only to postgres
+			VolumeSource: v1.VolumeSource{
+				EmptyDir: &v1.EmptyDirVolumeSource{},
+			},
+		},
 	}
 
 	pg := acidv1.Postgresql{
@@ -1865,7 +1884,7 @@ func TestAdditionalVolume(t *testing.T) {
 		{
 			subTest:        "checking volume mounts of postgres container",
 			container:      constants.PostgresContainerName,
-			expectedMounts: []string{"pgdata", "test1", "test3", "test4"},
+			expectedMounts: []string{"pgdata", "test1", "test3", "test4", "test5", "test6"},
 		},
 		{
 			subTest:        "checking volume mounts of sidecar container",