Fix query on PV info change

pkg/db/seeds/appuio_cloud_persistent_storage.promql

@@ -26,12 +26,14 @@ sum_over_time(
             on (cluster_id,persistentvolume)
             group_left(storageclass)
             # Do not differantiate between regular and encrypted storage class versions.
-            label_replace(
-              kube_persistentvolume_info,
-              "storageclass",
-              "$1",
-              "storageclass",
-              "([^-]+)-encrypted"
+            min by (cluster_id, persistentvolume, storageclass) (
+              label_replace(
+                kube_persistentvolume_info,
+                "storageclass",
+                "$1",
+                "storageclass",
+                "([^-]+)-encrypted"
+              )
             )
             *
             # Join the namespace label to get the tenant

pkg/db/seeds/promtest/appuio_cloud_persistent_storage.jsonnet

@@ -0,0 +1,81 @@
+local c = import 'common.libsonnet';
+
+local query = importstr '../appuio_cloud_persistent_storage.promql';
+
+local commonLabels = {
+  cluster_id: 'c-appuio-cloudscale-lpg-2',
+  tenant_id: 'c-appuio-cloudscale-lpg-2',
+};
+
+// One pvc, minimal (=1 byte) request
+// 10 samples
+local baseSeries = {
+  testprojectNamespaceOrgLabel: c.series('kube_namespace_labels', commonLabels {
+    namespace: 'testproject',
+    label_appuio_io_organization: 'cherry-pickers-inc',
+  }, '1x10'),
+
+  local pvcID = 'pvc-da01b12d-2e31-44da-8312-f91169256221',
+  pvCapacity: c.series('kube_persistentvolume_capacity_bytes', commonLabels {
+    persistentvolume: pvcID,
+  }, '1x10'),
+  pvInfo: c.series('kube_persistentvolume_info', commonLabels {
+    persistentvolume: pvcID,
+    storageclass: 'ssd',
+  }, '1x10'),
+  pvcRef: c.series('kube_persistentvolume_claim_ref', commonLabels {
+    claim_namespace: 'testproject',
+    name: 'important-database',
+    persistentvolume: pvcID,
+  }, '1x10'),
+};
+
+local baseCalculatedLabels = {
+  category: 'c-appuio-cloudscale-lpg-2:testproject',
+  cluster_id: 'c-appuio-cloudscale-lpg-2',
+  namespace: 'testproject',
+  product: 'appuio_cloud_persistent_storage:c-appuio-cloudscale-lpg-2:cherry-pickers-inc:testproject:ssd',
+  storageclass: 'ssd',
+  tenant_id: 'cherry-pickers-inc',
+};
+
+{
+  tests: [
+    c.test('minimal PVC',
+           baseSeries,
+           query,
+           {
+             labels: c.formatLabels(baseCalculatedLabels),
+             value: 10,
+           }),
+    c.test('higher than 1GiB request',
+           baseSeries {
+             pvCapacity+: {
+               values: '%sx10' % (5 * 1024 * 1024 * 1024),
+             },
+           },
+           query,
+           {
+             labels: c.formatLabels(baseCalculatedLabels),
+             value: 5 * 10,
+           }),
+
+    c.test('unrelated kube_persistentvolume_info changes do not throw errors - there is an overlap since series go stale only after a few missed scrapes',
+           baseSeries {
+             pvInfo+: {
+               values: '1x10 _x10 stale',
+             },
+             pvInfoUpdated: self.pvInfo {
+               _labels+:: {
+                 csi_volume_handle: '672004be-a86b-44e0-b446-1255a1f8b340',
+               },
+               values: '_x5 1x15',
+             },
+           },
+           query,
+           {
+             labels: c.formatLabels(baseCalculatedLabels),
+             value: 10,
+           }),
+  ],
+}