terminate_tagged_instances_after_6_hours.py

from __future__ import print_function
import json
import boto3
from datetime import datetime, timedelta
from dateutil.tz import tzlocal

print('INFO: Loading function')

DRY_RUN = True  # Do not shut down instances


# Time (in seconds) after which the filtered instances must be terminated.
TERMINATE_AFTER_SECONDS = 21600

ec2 = boto3.client('ec2')

def lambda_handler(event, context):
    if DRY_RUN:
        print('INFO: running in Dry Run mode, no action will be taken')
    else:
        print('INFO: All long-running gitlab-runner instances will be terminated')

    now = datetime.now(tzlocal())
    now = now - timedelta(seconds=now.second, microseconds=now.microsecond)
    print (now)
    starttime = now - timedelta(seconds=TERMINATE_AFTER_SECONDS)
    print (starttime)


    terminate_instances = []
    active_instances = []

    describe_response = ec2.describe_instances(
        Filters=[
            {'Name': 'instance-state-name', 'Values': ['running']},
            {'Name': 'tag:some-key', 'Values': ['some-value']}
        ]
    )

    for reservation in describe_response['Reservations']:
        # Build the dimensions from the instances
        for instance in reservation['Instances']:
            instance_id = instance['InstanceId']
            instance_launch_time = instance['LaunchTime']
            if instance_launch_time < starttime:
                terminate_instances.append(instance_id)
            else:
                active_instances.append(instance_id)

    if not DRY_RUN and len(terminate_instances) > 0:
        ec2.terminate_instances(InstanceIds=terminate_instances)
        print('INFO: Terminated instances')

    print(json.dumps({
        'active': active_instances,
        'terminate': terminate_instances,
    }))


lambda_handler(TERMINATE_AFTER_SECONDS, 21600)