Adding FileSensor example

dags_airflow_ale_fsensor_exmp.py

@@ -0,0 +1,32 @@
+"""
+This is an example using a FileSensor
+
+
+
+"""
+
+import airflow.utils.dates
+from airflow import DAG
+from airflow.operators.dummy import DummyOperator
+from airflow.sensors.filesystem import FileSensor
+
+dag = DAG(
+    dag_id="fsensor_exmp",
+    start_date=airflow.utils.dates.days_ago(3),
+    schedule_interval=None,
+    description="A demonstration DAG using FileSensor.",
+    #The execution doesn't proceed if a task fails
+    default_args={"depends_on_past": True},
+)
+
+create_metrics = DummyOperator(task_id="create_metrics", dag=dag)
+
+for f_id in [1, 2, 3]:
+    wait = FileSensor(
+        task_id=f"wait_for_file_{f_id}",
+        filepath=f"/data/f_{f_id}/data.csv",
+        dag=dag,
+    )
+    copy = DummyOperator(task_id=f"copy_to_raw_supermarket_{f_id}", dag=dag)
+    process = DummyOperator(task_id=f"process_supermarket_{f_id}", dag=dag)
+    wait >> copy >> process >> create_metrics