Airflow cron-DAG demo (#115)

## Description

A simple Airflow demo showing how to import/load a custom DAG and schedule it by enabling and triggering it.



Co-authored-by: Sebastian Bernauer <[email protected]>

Author: adwk67

demos/airflow-scheduled-job/enable-and-run-dag.yaml

@@ -0,0 +1,17 @@
+---
+apiVersion: batch/v1
+kind: Job
+metadata:
+  name: start-dag-job
+spec:
+  template:
+    spec:
+      containers:
+        - name: start-dag-job
+          image: docker.stackable.tech/stackable/testing-tools:0.1.0-stackable0.1.0
+          command: ["bash", "-c", "
+          curl -s --user airflow:airflow -H 'Content-Type:application/json' -XPATCH http://airflow-webserver-default:8080/api/v1/dags/date_demo -d '{\"is_paused\": false}'
+          && curl -s --user airflow:airflow -H 'Content-Type:application/json' -XPOST http://airflow-webserver-default:8080/api/v1/dags/date_demo/dagRuns -d '{}'
+          "]
+      restartPolicy: OnFailure
+  backoffLimit: 20 # give some time for the Airflow cluster to be available

demos/demos-v1.yaml

@@ -55,3 +55,11 @@ demos:
     manifests:
       - plainYaml: https://raw.githubusercontent.com/stackabletech/stackablectl/main/demos/hbase-hdfs-load-cycling-data/01-distcp-cycling-data.yaml
       - plainYaml: https://raw.githubusercontent.com/stackabletech/stackablectl/main/demos/hbase-hdfs-load-cycling-data/02-create-hfile-and-import-to-hbase.yaml
+  airflow-scheduled-job:
+    description: Activate a simple Airflow DAG to run continously at a set interval
+    stackableStack: airflow
+    labels:
+      - airflow
+      - job-scheduling
+    manifests:
+      - plainYaml: https://raw.githubusercontent.com/stackabletech/stackablectl/main/demos/airflow-scheduled-job/enable-and-run-dag.yaml