python-stop-instances.py

""" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 
INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, 
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. """

from __future__ import print_function
import urllib
import boto3
import csv
import codecs


def get_bucket_and_filename(record):
    """Extract S3 Bucket Name and File Name from event record"""
    try:
        bucket = record['s3']['bucket']['name']
        key = urllib.unquote_plus(record['s3']['object']['key'])
    except KeyError as ke:
        print('Failed to retrieve bucket or filename, KeyError:', ke)
        raise
    except Exception as e:
        print('Failed to retrieve bucket or filename, Exception:', e)
        raise
    return bucket, key


def get_csvfile(record):
    """Get csv file stream from S3"""
    try:
        bucket, key = get_bucket_and_filename(record)
        s3 = boto3.resource('s3')
        csvfile = s3.ObjectSummary(bucket, key).get()
        print("csvfile: ", csvfile)
    except Exception as e:
        print('Failed to get csv file, Exception:', e)
        raise
    return csvfile


def get_instances(csvfile, idcolumn='InstanceID', regioncolumn='Region'):
    """Get Instance IDs by Regions from csv
       Return a dictionary in the format {Region: [InstanceId, InstanceId, ...], ...}
       e.g. {'us-west-2': ['i-01234567'], 'us-east-1': ['i-01234568', 'i-01234569', 'i-01234570']}"""
    try:
        csvreader = csv.DictReader(codecs.getreader('utf-8')(csvfile['Body']))
        # get Instance IDs and Regions
        instances = {}
        for row in csvreader:
            # print("row: ", row)
            if not row[regioncolumn] in instances:
                instances[row[regioncolumn]] = []
            instances[row[regioncolumn]].append(row[idcolumn])
    except Exception as e:
        print('Failed to retrieve instance ids, Exception:', e)
        raise
    return instances


def stop_instances(instances):
    """stop Instances by ids and regions"""
    for region in instances:
        print(region, instances[region])
        try:
            ec2 = boto3.client('ec2', region)
            ec2.stop_instances(InstanceIds=instances[region])
            print('stopped instances: ', str(instances[region]))
        except Exception as e:
            print('Failed to stop instances, Exception:', e)
            raise


def lambda_handler(event, context):
    for record in event['Records']:
        try:
            csvfile = get_csvfile(record)
            instances = get_instances(csvfile)
            print('instances: ', instances)
            stop_instances(instances)
        except Exception:
            continue