chore: Sample dags minor cleanup (#344)

Signed-off-by: Tao Feng <fengtao04@gmail.com>

example/dags/hive_sample_dag.py

@@ -199,3 +199,7 @@ with DAG('amundsen_databuilder', default_args=default_args, **dag_args) as dag:
                         'watermark_type': '"low_watermark"',
                         'part_regex': '{}'.format('{{ ds }}')}
     )
+
+    # Schedule high and low watermark task after metadata task
+    amundsen_databuilder_table_metadata_job >> amundsen_hwm_job
+    amundsen_databuilder_table_metadata_job >> amundsen_lwm_job

example/dags/postgres_sample_dag.py

@@ -75,7 +75,7 @@ def connection_string():
     return "postgresql://%s:%s@%s:%s/%s" % (user, password, host, port, db)
 
 
-def create_table_extract_job(**kwargs):
+def create_table_extract_job():
     where_clause_suffix = textwrap.dedent("""
         where table_schema in {schemas}
     """).format(schemas=SUPPORTED_SCHEMA_SQL_IN_CLAUSE)
@@ -161,15 +161,15 @@ def create_es_publisher_sample_job():
 
 with DAG('amundsen_databuilder', default_args=default_args, **dag_args) as dag:
 
-    create_table_extract_job = PythonOperator(
-        task_id='create_table_extract_job',
+    postgres_table_extract_job = PythonOperator(
+        task_id='postgres_table_extract_job',
         python_callable=create_table_extract_job
     )
 
-    create_es_index_job = PythonOperator(
-        task_id='create_es_publisher_sample_job',
+    postgres_es_index_job = PythonOperator(
+        task_id='postgres_es_publisher_sample_job',
         python_callable=create_es_publisher_sample_job
     )
 
     # elastic search update run after table metadata has been updated
-    create_table_extract_job >> create_es_index_job
+    postgres_table_extract_job >> postgres_es_index_job