Fixes #12847 - Handle kubernetes cron job aliases

Signed-off-by: Jonathan Stacks <jonstacks13@gmail.com>

plugins/kubernetes/src/components/CronJobsAccordions/CronJobsAccordions.tsx

@@ -29,7 +29,7 @@ import { CronJobDrawer } from './CronJobsDrawer';
 import { getOwnedResources } from '../../utils/owner';
 import { GroupedResponsesContext } from '../../hooks';
 import { StatusError, StatusOK } from '@backstage/core-components';
-import cronstrue from 'cronstrue';
+import { humanizeCron } from '../../utils/crons';
 
 type CronJobsAccordionsProps = {
   children?: React.ReactNode;
@@ -79,7 +79,7 @@ const CronJobSummary = ({ cronJob }: CronJobSummaryProps) => {
           <Typography variant="body1">
             Schedule:{' '}
             {cronJob.spec?.schedule
-              ? `${cronJob.spec.schedule} (${cronstrue.toString(
+              ? `${cronJob.spec.schedule} (${humanizeCron(
                   cronJob.spec.schedule,
                 )})`
               : 'N/A'}

plugins/kubernetes/src/utils/crons.test.ts

@@ -0,0 +1,52 @@
+/*
+ * Copyright 2021 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { humanizeCron } from './crons';
+
+describe('crons', () => {
+  describe('humanizeCron', () => {
+    it('should handle kubernetes aliases', () => {
+      expect(humanizeCron('@yearly')).toBe(
+        'At 12:00 AM, on day 1 of the month, only in January',
+      );
+      expect(humanizeCron('@annually')).toBe(
+        'At 12:00 AM, on day 1 of the month, only in January',
+      );
+      expect(humanizeCron('@monthly')).toBe(
+        'At 12:00 AM, on day 1 of the month',
+      );
+      expect(humanizeCron('@weekly')).toBe('At 12:00 AM, only on Sunday');
+      expect(humanizeCron('@daily')).toBe('At 12:00 AM');
+      expect(humanizeCron('@midnight')).toBe('At 12:00 AM');
+      expect(humanizeCron('@hourly')).toBe('Every hour');
+    });
+
+    it('should handle regular crons', () => {
+      expect(humanizeCron('0 23 * * *')).toBe('At 11:00 PM');
+      expect(humanizeCron('0 0 13 * 5')).toBe(
+        'At 12:00 AM, on day 13 of the month, and on Friday',
+      );
+    });
+
+    it('should handle empty strings', () => {
+      expect(humanizeCron('')).toBe('');
+    });
+
+    it('should return the original schedule rather than throwing an error', () => {
+      expect(humanizeCron('@invalid')).toBe('@invalid');
+    });
+  });
+});

plugins/kubernetes/src/utils/crons.ts

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2021 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import cronstrue from 'cronstrue';
+
+// Defined at https://kubernetes.io/docs/concepts/workloads/controllers/cron-jobs/
+const k8sCronAliases = new Map([
+  ['@yearly', '0 0 1 1 *'],
+  ['@annually', '0 0 1 1 *'],
+  ['@monthly', '0 0 1 * *'],
+  ['@weekly', '0 0 * * 0'],
+  ['@daily', '0 0 * * *'],
+  ['@midnight', '0 0 * * *'],
+  ['@hourly', '0 * * * *'],
+]);
+
+// humanizeCron takes into account the aliases provided by kubernetes before
+// calling cronstrue. In an effort to not throw an error, it will return the
+// original cron formatted schedule if the cronstrue call fails.
+export const humanizeCron = (schedule: string): string => {
+  const deAliasedSchedule = k8sCronAliases.get(schedule) || schedule;
+  try {
+    return cronstrue.toString(deAliasedSchedule);
+  } catch (e) {
+    return deAliasedSchedule;
+  }
+};