aws lambda for executing run command using python

README.md

aws lambda for executing run command using python

you must have following pre-requsite

instance_id = '' # hard-code for example

document_name = '<>' # run command document name

command_param = {'commands': ['sh /root/shellscript.sh '+ shellparam]}, # shell script path

s3_bucket = 'mybucket' # to store the logs

s3_region = 'eu-west-1'

sns_arn = '<>' # for notification

sns_role_arn = '<>' # to push the notificatan the role must have assume role permission

dynamodb_table = '<>' # to store the status and shell param

lambda_run_command.py

#!/usr/bin/python
# -*- coding: utf-8 -*-
import boto3
import botocore
import time
import json
from pprint import pprint
from botocore.exceptions import ClientError
from boto3.dynamodb.conditions import Key

instance_id = '<instance id>'  # hard-code for example
document_name = '<>' # run command document name
command_param = {'commands': ['sh /root/shellscript.sh '+ shellparam]}, # shell script path
s3_bucket = 'mybucket'
s3_region = 'eu-west-1'
sns_arn = '<>'
sns_role_arn = '<>'
dynamodb_table = '<>'

def lambda_handler(event=None, context=None):
    _log(event)
    #prase event
    shellparam = '';
    if(isinstance(event, str)):
        event = json.loads(event)
    if("shellparam" in event):
        shellparam = event["shellparam"]
    
    if not shellparam:
        _log("Exiting : blank shellparam "+shellparam);
        return False
   
            
    client = boto3.client('ssm')
    _log("Stating with shellparam : " + shellparam);

    # all well, so start the shell script execution
   
    response = client.send_command(  
        InstanceIds=[instance_id],
        DocumentName=document_name, 
        Parameters=command_param,
        OutputS3Region=s3_region, 
        OutputS3BucketName=s3_bucket,
        OutputS3KeyPrefix='/lambda/log'+shellparam,
        NotificationConfig={'NotificationArn': sns_arn # notification arn
                            , 'NotificationEvents': ['All'],
                            'NotificationType': 'Command'},
        ServiceRoleArn=sns_role_arn, # service role arn 
        )
    command_id = response['Command']['CommandId']
    _log('Gettign command id ' + command_id)
    
    # create an entry in table
    db_record_created = create_record(command_id, shellparam, '',
            instance_id)
    if db_record_created:
        _log("Command Invocation");
        time.sleep(0.5)  # some delay always required...
        result = client.get_command_invocation(CommandId=command_id,
                InstanceId=instance_id)
        output = result['StandardOutputContent']
        _log('Final result')
        _log(result)
        return True
    else:
        _log('Request could not processed.')
        # delete record
        delete_record(command_id)
        return false


def delete_record(commandid):
    dynamodb = boto3.resource('dynamodb')
    table = dynamodb.Table(dynamodb_table)
    _log('Deleting command id ' + commandid)
    try:
        response = table.delete_item(Key={'commandid': commandid})
    except ClientError as e:
        _log(e.response['Error']['Message'])
        return False
    else:
        return True


def check_shellparam(shellparam):
    dynamodb = boto3.resource('dynamodb')
    table = dynamodb.Table(dynamodb_table)
    _log('checking shellparam availability ' + shellparam)
    try:
        response = table.scan(FilterExpression=Key('shellparam').eq(shellparam))

        _log(response)
    except ClientError as e:
        _log(e.response['Error']['Message'])
        return False
    else:
        return response['Count']


def create_record(
    commandid,
    shellparam,
    status,
    instanceid,
    ):
    dynamodb = boto3.resource('dynamodb')
    table = dynamodb.Table(dynamodb_table)
    _log('create record')
    try:
        response = table.put_item(Item={
            'commandid': commandid,
            'shellparam': shellparam,
            'cmdstatus': status,
            'info': {'instanceid': instanceid},
            })

        _log(response)
    except ClientError as e:
        _log(e.response['Error']['Message'])
        return False
    else:
        return True


def _log(str):
    print(str)