Add Airflow version in the Slack report for master DAG run

Use a BashOperator to get the airflow version and pushes the result
to XCOM. Pass `context` to Slack report task so that it can pull
the airflow version from XCOM pushed by the BashOperator.

Author: pankajkoti

.circleci/integration-tests/master_dag.py

@@ -2,7 +2,7 @@
 import os
 import time
 from datetime import datetime
-from typing import List
+from typing import Any, List
 
 from airflow import DAG
 from airflow.contrib.operators.slack_webhook_operator import SlackWebhookOperator
@@ -19,7 +19,7 @@
 SLACK_USERNAME = os.getenv("SLACK_USERNAME", "airflow_app")
 
 
-def get_report(dag_run_ids: List[str]) -> None:
+def get_report(dag_run_ids: List[str], **context: Any) -> None:
     """Fetch dags run details and generate report"""
     with create_session() as session:
         last_dags_runs: List[DagRun] = session.query(DagRun).filter(DagRun.run_id.in_(dag_run_ids)).all()
@@ -39,6 +39,10 @@ def get_report(dag_run_ids: List[str]) -> None:
                     task_message_str = f"{task_code} {ti.task_id} : {ti.state} \n"
                     message_list.append(task_message_str)
 
+        airflow_version = context["ti"].xcom_pull(task_ids="get_airflow_version")
+        airflow_version_message = f"\n\nAirflow version for the run is `{airflow_version}`"
+        message_list.append(airflow_version_message)
+
         logging.info("%s", "".join(message_list))
         # Send dag run report on Slack
         try:
@@ -94,6 +98,10 @@ def prepare_dag_dependency(task_info, execution_time):
         task_id="list_installed_pip_packages", bash_command="pip freeze"
     )
 
+    get_airflow_version = BashOperator(
+        task_id="get_airflow_version", bash_command="airflow version", do_xcom_push=True
+    )
+
     dag_run_ids = []
     # AWS S3 and Redshift DAG
     amazon_task_info = [
@@ -194,6 +202,7 @@ def prepare_dag_dependency(task_info, execution_time):
         python_callable=get_report,
         op_kwargs={"dag_run_ids": dag_run_ids},
         trigger_rule="all_done",
+        provide_context=True,
     )
 
     end = DummyOperator(
@@ -203,6 +212,7 @@ def prepare_dag_dependency(task_info, execution_time):
 
     start >> [
         list_installed_pip_packages,
+        get_airflow_version,
         amazon_trigger_tasks[0],
         emr_trigger_tasks[0],
         google_trigger_tasks[0],
@@ -218,6 +228,7 @@ def prepare_dag_dependency(task_info, execution_time):
 
     last_task = [
         list_installed_pip_packages,
+        get_airflow_version,
         amazon_trigger_tasks[-1],
         emr_trigger_tasks[-1],
         google_trigger_tasks[-1],