ilds-st.py

import boto3
import json
import glob
import sys
import os
import re

# Get latest version of task definition.
def list_image(taskdefname):
    client = boto3.client('ecs')
    response = client.list_task_definitions(
        familyPrefix=taskdefname,
        sort='DESC',
        status='ACTIVE',
        maxResults=1
    )
    return response['taskDefinitionArns'][0]


# Function to create new scheduled tasks.
def create_new_scheduled_task(client, rulename, container_name, st_state, scheduledExpression):
    response = client.put_rule(
        Name=rulename,
        ScheduleExpression=scheduledExpression,
        State=st_state,
        Description='Scheduled tasks created/updated by python script.',
        RoleArn="arn:aws:iam::975474249947:role/ecsEventsRole"
    )

    print('Http code: {}'.format(response['ResponseMetadata']['HTTPStatusCode']))

    response = client.put_targets(
    Rule=rule_name,
    Targets=[
        {
                "Input":""" 
                    {
                        "containerOverrides": [
                            {
                            "name": "%s",
                            "command": ["npm", "run", "%s"]
                            }
                        ]
                    }
                """ % (container_name,rule_name),        
                'Id': rule_name,
                'Arn': ECSClusterArn,
                'RoleArn': "arn:aws:iam::975474249947:role/ecsEventsRole",
                'EcsParameters': {
                    'TaskDefinitionArn': task_def_arn,
                    'TaskCount': 1,
                    'LaunchType': 'FARGATE',
                    'PlatformVersion': 'LATEST',
                    'NetworkConfiguration': {
                        'awsvpcConfiguration': {
                            'Subnets': [
                                subnet1,
                                subnet2
                            ],
                            'SecurityGroups': [
                                SecurityGroup,
                            ],
                            'AssignPublicIp': 'DISABLED'
                        }
                    },                      
                },
            },
        ]
    ) 

    print('Http code: {}'.format(response['ResponseMetadata']['HTTPStatusCode']))

# Function to get cron schedule defined on first line of file.
def get_cron_schedule(file):
    # Function to parse file and read first line.
    infile = open(file, 'r')
    firstLine = infile.readline()

    cronschedule = ''.join(firstLine.split('//', 1)).strip()
    return cronschedule

# If Scheduled tasks already exists then this fuction will get the current state of Scheduled tasks. whether its in ENABLED or DISABLED state.
def get_sts_state(rule_name):
    client = boto3.client('events')
    try: 
        response = client.list_rules(
            NamePrefix=rule_name,
            Limit=2
        )
        st_state = response['Rules'][0]['State']
        return st_state
    except IndexError:
        st_state = "ENABLED"
        return st_state  

# Specify the name of Task definition.

taskdefname = sys.argv[1]
subnet1 = sys.argv[2]
subnet2 = sys.argv[3]
SecurityGroup = sys.argv[4]
ECSClusterArn = sys.argv[5]
TaskRoleArn = sys.argv[6]
container_name = sys.argv[7]
task_def_arn = list_image(taskdefname)


# Get list of all files with .ts extension and create scheduled tasks for those.
tsfile = glob.glob("*.ts")
for f in tsfile:

    # Check if first line contains any cron expression.
    infile = open(f, 'r')
    firstLine = infile.readline()
    if "cron" in firstLine:
        rule_name = f.rsplit( ".", 1 )[ 0 ]
        cron_schedule = get_cron_schedule(f)
        st_state = get_sts_state(rule_name)

        if st_state == "ENABLED":
            # Create new client to work with events.
            client = boto3.client('events')
            create_new_scheduled_task(client, rule_name, container_name, st_state, cron_schedule)