feat: Add SubPathExpr option for additionalVolumes (#2463)

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

@@ -242,6 +242,7 @@ 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

@@ -83,6 +83,16 @@ 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

@@ -168,6 +168,9 @@ var PostgresCRDResourceValidation = apiextv1.CustomResourceValidation{
 									"subPath": {
 										Type: "string",
 									},
+									"isSubPathExpr": {
+										Type: "boolean",
+									},
 								},
 							},
 						},

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

@@ -143,6 +143,7 @@ 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

@@ -1820,11 +1820,18 @@ 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

@@ -1889,6 +1889,25 @@ func TestAdditionalVolume(t *testing.T) {
 				EmptyDir: &v1.EmptyDirVolumeSource{},
 			},
 		},
+		{
+			Name:             "test5",
+			MountPath:        "/test5",
+			SubPath:          "subpath",
+			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{
@@ -1935,9 +1954,10 @@ func TestAdditionalVolume(t *testing.T) {
 	assert.NoError(t, err)
 
 	tests := []struct {
-		subTest        string
-		container      string
-		expectedMounts []string
+		subTest         string
+		container       string
+		expectedMounts  []string
+		expectedSubPath []string
 	}{
 		{
 			subTest:        "checking volume mounts of postgres container",
@@ -1949,6 +1969,17 @@ func TestAdditionalVolume(t *testing.T) {
 			container:      "sidecar",
 			expectedMounts: []string{"pgdata", "test1", "test2"},
 		},
+		{
+			subTest:         "checking volume mounts with subPath",
+			container:       constants.PostgresContainerName,
+			expectedMounts:  []string{"test5"},
+			expectedSubPath: []string{"subpath"},
+		},
+		{
+			subTest:        "checking volume mounts with subPathExpr",
+			container:      constants.PostgresContainerName,
+			expectedMounts: []string{"test6"},
+		},
 	}
 
 	for _, tt := range tests {
@@ -1957,12 +1988,26 @@ func TestAdditionalVolume(t *testing.T) {
 				continue
 			}
 			mounts := []string{}
+			subPaths := []string{}
+			subPathExprs := []string{}
 			for _, volumeMounts := range container.VolumeMounts {
 				mounts = append(mounts, volumeMounts.Name)
+				subPaths = append(subPaths, volumeMounts.SubPath)
+				subPathExprs = append(subPathExprs, volumeMounts.SubPathExpr)
 			}
 
 			if !util.IsEqualIgnoreOrder(mounts, tt.expectedMounts) {
-				t.Errorf("%s %s: different volume mounts: got %v, epxected %v",
+				t.Errorf("%s %s: different volume mounts: got %v, expected %v",
+					t.Name(), tt.subTest, mounts, tt.expectedMounts)
+			}
+
+			if !util.IsEqualIgnoreOrder(subPaths, tt.expectedSubPath) {
+				t.Errorf("%s %s: different volume subPaths: got %v, expected %v",
+					t.Name(), tt.subTest, mounts, tt.expectedSubPath)
+			}
+
+			if !util.IsEqualIgnoreOrder(subPathExprs, []string{container.Name}) {
+				t.Errorf("%s %s: different volume subPathExprs: got %v, expected %v",
 					t.Name(), tt.subTest, mounts, tt.expectedMounts)
 			}
 		}