backup_vm_instance.py

# Copyright 2018 Google LLC
#
# 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
#
#     https://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.

"""Airflow DAG to backup a Compute Engine virtual machine instance."""

import datetime
from airflow import DAG
from airflow.models import Variable
from gcp_custom_ops.gce_commands import OperationStatusSensor
from gcp_custom_ops.gce_commands import SnapshotDiskOperator
from gcp_custom_ops.gce_commands import StartInstanceOperator
from gcp_custom_ops.gce_commands import StopInstanceOperator
from airflow.operators.dummy_operator import DummyOperator

INTERVAL = '@daily'
START_DATE = datetime.datetime(2018, 7, 16)
PROJECT = Variable.get('PROJECT')
ZONE = Variable.get('ZONE')
INSTANCE = Variable.get('INSTANCE')
DISK = Variable.get('DISK')

# Airflow operators definition
dag1 = DAG('backup_vm_instance',
           description='Backup a Compute Engine instance using an Airflow DAG',
           schedule_interval=INTERVAL,
           start_date=START_DATE,
           catchup=False)

## Dummy tasks
begin = DummyOperator(task_id='begin', retries=1, dag=dag1)
end = DummyOperator(task_id='end', retries=1)

## Compute Engine tasks
stop_instance = StopInstanceOperator(
    project=PROJECT, zone=ZONE, instance=INSTANCE, task_id='stop_instance')
snapshot_disk = SnapshotDiskOperator(
    project=PROJECT, zone=ZONE, instance=INSTANCE,
    disk=DISK, task_id='snapshot_disk')
start_instance = StartInstanceOperator(
    project=PROJECT, zone=ZONE, instance=INSTANCE, task_id='start_instance')

# [START wait_tasks]
## Wait tasks
wait_for_stop = OperationStatusSensor(
    project=PROJECT, zone=ZONE, instance=INSTANCE,
    prior_task_id='stop_instance', poke_interval=15, task_id='wait_for_stop')
wait_for_snapshot = OperationStatusSensor(
    project=PROJECT, zone=ZONE, instance=INSTANCE,
    prior_task_id='snapshot_disk', poke_interval=10,
    task_id='wait_for_snapshot')
wait_for_start = OperationStatusSensor(
    project=PROJECT, zone=ZONE, instance=INSTANCE,
    prior_task_id='start_instance', poke_interval=5, task_id='wait_for_start')
# [END wait_tasks]

# Airflow DAG definition
begin >> stop_instance >> wait_for_stop >> snapshot_disk >> wait_for_snapshot \
        >> start_instance >> wait_for_start >> end