AWS Lambda to auto start stop Ec2 instance on schedule using python and boto3

Use this lambda function to auto start stop all Ec2 instances based on schedule from tags.

aws ec2 auto start stop lambda


#Auto Shutodown - Start EC2 instances based on tags
import boto3
import os
import json
import croniter
import datetime
# Enter the region your instances are in. Include only the region without specifying Availability Zone; e.g., 'us-east-1'
region = 'us-west-2'

EC2_STATUS_CODE_RUNNING = 16
EC2_STATUS_CODE_STOPPED = 80

def lambda_handler(event, context):
ec2 = boto3.client('ec2', region_name=region)

#auto_start_stop_tag = 'tc:uptime_schedule_gmt'
auto_start_tag = 'tc:start_time_schedule_gmt_24h_format'
auto_shutdown_tag = 'tc:shutdown_time_schedule_gmt_24h_format'

instances_to_shutdown = []
instances_to_start = []
# Query ec2 machines for auto_start_stop_tag,
#instances_with_schedules = get_instance_schedules(auto_start_stop_tag)
instances_with_start_schedules = get_instance_schedules(auto_start_tag)
instances_with_shutdown_schedules = get_instance_schedules(auto_shutdown_tag)
print("instances_with_start_schedules: %s" % instances_with_start_schedules)
print("instances_with_shutdown_schedules: %s" % instances_with_shutdown_schedules)

for instance_id, values in instances_with_start_schedules.items():
now = datetime.datetime.now()
print("now: %s" % now)
iterator = croniter.croniter(values['Schedule'], now)
next_run_time = iterator.get_next(datetime.datetime)
print("next_run_time: %s" % next_run_time)
duration_until_next_run_time = next_run_time - now
print("duration_until_next_start_time: %s" % duration_until_next_run_time)
duration_of_one_hour = datetime.timedelta(hours=1)

if duration_until_next_run_time <= duration_of_one_hour and values['State']['Code'] == EC2_STATUS_CODE_STOPPED: print("true") print("instance_to_stop.append(%s)" % instance_id) instances_to_start.append(instance_id) for instance_id, values in instances_with_shutdown_schedules.items(): now = datetime.datetime.now() print("now: %s" % now) iterator = croniter.croniter(values['Schedule'], now) next_run_time = iterator.get_next(datetime.datetime) print("next_run_time: %s" % next_run_time) duration_until_next_run_time = next_run_time - now print("duration_until_next_shutdown_time: %s" % duration_until_next_run_time) duration_of_one_hour = datetime.timedelta(hours=1) if duration_until_next_run_time <= duration_of_one_hour and values['State']['Code'] == EC2_STATUS_CODE_RUNNING: print("instance_to_shutdown.append(%s)" % instance_id) instances_to_shutdown.append(instance_id) if len(instances_to_shutdown) > 0:
ec2.stop_instances(InstanceIds=instances_to_shutdown)
print('stopped your instances: ' + str(instances_to_shutdown))
send_shutdown_notification(instances_to_shutdown, "STOPPED")

if len(instances_to_start) > 0:
ec2.start_instances(InstanceIds=instances_to_start)
print('started your instances: ' + str(instances_to_start))
send_start_notification(instances_to_start, "STARTED")

def send_shutdown_notification(instances, event):
instances_json_object = {"instances":instances, "event":event}
instances_json_string = json.dumps(instances_json_object)
instances_json_bytes = instances_json_string.encode('utf-8')

lambda_arn = os.environ['LAMBDA_NOTIFICATION_SHUTDOWN_ARN']
lambda_client = boto3.client("lambda")
lambda_client.invoke(
FunctionName=lambda_arn,
InvocationType='Event',
LogType='None',
Payload=instances_json_bytes
)

def send_start_notification(instances, event):
instances_json_object = {"instances":instances, "event":event}
instances_json_string = json.dumps(instances_json_object)
instances_json_bytes = instances_json_string.encode('utf-8')

lambda_arn = os.environ['LAMBDA_NOTIFICATION_START_ARN']
lambda_client = boto3.client("lambda")
lambda_client.invoke(
FunctionName=lambda_arn,
InvocationType='Event',
LogType='None',
Payload=instances_json_bytes
)

def get_instance_schedules(tag_name):
# When passed a tag key, tag value this will return a list of InstanceIds that were found.

ec2client = boto3.client('ec2')

response = ec2client.describe_instances(
Filters=[
{
'Name': 'tag-key',
'Values': [tag_name]
}
]
)
instancelist = {}
for reservation in (response["Reservations"]):
for instance in reservation["Instances"]:
tag_value = ''
for tag in instance['Tags']:
if tag['Key'] == tag_name:
tag_value = tag['Value']
break
instancelist[instance["InstanceId"]] = {'Schedule':tag_value,'State':instance['State']}

return instancelist

Get all All AWS Ec2 snapshop reports with python and boto3

Use this python script to get all EC2 snapshot report in your AWS account.

AWS EC2 snapshop report


import boto3
def lambda_handler(event, context):
session = boto3.Session(profile_name='saml')
ec2client = session.client('ec2')
instances_with_volumes = get_instance_ids(ec2client, "tc:OpsAutomatorTaskList")

for instance_id, volume_ids in instances_with_volumes.items():
response = ec2client.describe_snapshots(
Filters = [
{'Name':'volume-id', 'Values': volume_ids}
#{'Name':'start-time', 'Values': ['2019-01-01']}
]
#MaxResults = 10
)
#print(response['ResponseMetadata'])
#print("instance_id:%s, number_of_snapshots:%s" % (instance_id, len(response['Snapshots'])))
if len(response['Snapshots']) > 0:
#print(response['Tags'])
#Print Header
print('InstanceId' + ' , ' + 'Description' + ' , ' + 'Encrypted' + ' , ' + 'OwnerId' + ' , ' + 'Progress' + ' , ' + 'SnapshotId' + ' , ' + 'StartTime' + ' , ' + 'State' + ' , ' + 'VolumeId' + ' , ' + 'VolumeSize')
for snapshot in response['Snapshots']:
print(instance_id + ' , ' + snapshot['Description'] + ' , ' + str(snapshot['Encrypted']) + ' , ' + str(snapshot['OwnerId']) + ' , ' + snapshot['Progress'] + ' , ' + snapshot['SnapshotId'] + ' , ' + str(snapshot['StartTime']) + ' , ' + snapshot['State'] + ' , ' + snapshot['VolumeId'] + ' , ' + str(snapshot['VolumeSize']) )

def get_instance_ids(ec2client, tag_name):
# When passed a tag key, tag value this will return a list of InstanceIds that were found.

response = ec2client.describe_instances(
Filters=[
{
'Name': 'tag-key',
'Values': [tag_name]
}
]
)
instancelist = {}
for reservation in (response["Reservations"]):
for instance in reservation["Instances"]:

ebs_volume_ids = []
for ebs in instance['BlockDeviceMappings']:
ebs_volume_ids.append(ebs['Ebs']['VolumeId'])

instancelist[instance["InstanceId"]] = ebs_volume_ids

return instancelist

lambda_handler('','')

Quicksort Algorithm Implementation with Python

QuickSort is an O(nlogn) efficient sorting algorithm, serving as systematic method for placing elements of an array in order. Quicksort is a comparison sort, meaning that it can sort items of any type for which a “less-than” relation (formally, a total order) is defined. In efficient implementations it is not a stable sort, meaning that the relative order of equal sort items is not preserved. Quicksort can operate in-place on an array, requiring small additional amounts of memory to perform the sorting. It is very similar to selection sort, except that it does not always choose worst-case partition.
Source: https://en.wikipedia.org/wiki/Quicksort
Below are 2 versions of the Quicksort Algorithm Implementation with Python. The first version is easy, but use more memory. The second version use the memory very efficiently.




I- QuickSort Algorithm Implementation with Python (Memory intensive version)

QuickSort Algorithm Implementation with Python method1

Output:

II- Quicksort Algorithm Implementation with Python (with Memory Optimisation)

III- QuickSort Algorithm Implementation with Python for Both Methods with duration captured

Output

Binary Search Algorithm Implementation with Python

Binary Search  is an algorithm that finds the position of a target in a sorted array. Binary search compares the target value to the middle element of the array. If they are not equal, the half in which the target cannot lie is eliminated and the search continues on the remaining half, again taking the middle element to compare to the target value, and repeating this until the target value is found. If the search ends with the remaining half being empty, the target is not in the array. Even though the idea is simple, implementing binary search correctly requires attention to some subtleties about its exit conditions and midpoint calculation, particularly if the values in the array are not all of the whole numbers in the range.

Source: https://en.wikipedia.org/wiki/Binary_search_algorithm

Below the binary search algorithm implementation  with python:





#Test_Binary_Search.py
Array=[-2,1,0,4,7,8,10,13,16,17, 21,30,45,100,150,160,191,200]
Target=201
n=len(Array)
def binarySearch(A,T):
L=0
R=n-1
while (L <= R):
m=int((L + R)/2)
if ( A[m] < T ):
L = m +1
elif (A[m] > T):
R = m-1
else:
print("Target is at %s:" % m)
return m
print("Target not found")
return "unsuccessful"

binarySearch(Array, Target)

Binary Search Algorithm implementation with python

Script with hash tables on windows and Linux

How to declare and write a script with hash tables on windows and linux

  • Hash tables with powershell on windows

    Declaration:
    $states=@{“Alberta” = “Calgary”; “British Columbia” = “Vancouver”; “Ontario” = “Toronto” ; “Quebec” = “Montreal”}

    Name
    _____
    Value
    _______
    Alberta Calgary
    British Columbia Vancouver
    Ontario Toronto
    Quebec Montreal

    Add new key-value in hashtable:
    $states.Add(“Manitoba”,”Winnipeg”)

    Remove key-value in hashtable:
    $states.Remove(“Manitoba”,”Winnipeg”)
    Change value in hashtable:
    $states.Set_Item(“Ontario”,”Ottawa”)
    Retrieve value in hashtable:
    $states.Get_Item(“Alberta”)
    Find key in hashtable:
    $states.ContainsKey(“Alberta”)
    Find Value in hashtable:
    $states.ContainsValue(“Calgary”)
    Count items in hashtable:
    $states.Count
    Sort items by Name in hashtable:
    $states.GetEnumerator() | Sort-Object Name -descending
    Sort items by Value in hashtable:
    $states.GetEnumerator() | Sort-Object Value -descending

  • Hash tables with perl on linux or windows

     
    Declaration:
    my %hash = (); #Initialize a hash
    my $hash_ref = {}; # Initialize a hash reference. ref will return HASH
    Clear (or empty) a hash
    for (keys %hash)
    {
    delete $hash{$_};
    }
    Clear (or empty) a hash reference
    for (keys %$href)
    {
    delete $href->{$_};
    }
    Add a key/value pair to a hash
    $hash{ ‘key’ } = ‘value’; # hash
    $hash{ $key } = $value; # hash, using variables
    Using Hash Reference
    $href->{ ‘key’ } = ‘value’; # hash ref
    $href->{ $key } = $value; # hash ref, using variables
    Add several key/value pairs to a hash
    %hash = ( ‘key1’, ‘value1’, ‘key2’, ‘value2’, ‘key3’, ‘value3’ );
    %hash = (
    key1 => ‘value1’,
    key2 => ‘value2’,
    key3 => ‘value3’,
    );

    Copy a hash
    my %hash_copy = %hash; # copy a hash
    my $href_copy = $href; # copy a hash ref
    Delete a single key/value pair
    delete $hash{$key};
    delete $hash_ref->{$key};

  • Hash tables with python on linux or windows

    Hash tables are called dictionary in python.
    Declaration:
    dict = {‘Name’: ‘Zara’, ‘Age’: 7, ‘Class’: ‘First’}
    Accessing Values
    print “dict[‘Name’]: “, dict[‘Name’]
    print “dict[‘Age’]: “, dict[‘Age’]
    Output:
    dict[‘Name’]: Zara
    dict[‘Age’]: 7
    Updating Dictionary
    dict = {‘Name’: ‘Zara’, ‘Age’: 7, ‘Class’: ‘First’}

    dict[‘Age’] = 8; # update existing entry
    dict[‘School’] = “DPS School”; # Add new entry
    Delete Dictionary Elements
    #!/usr/bin/python

    dict = {‘Name’: ‘Zara’, ‘Age’: 7, ‘Class’: ‘First’}

    del dict[‘Name’]; # remove entry with key ‘Name’
    dict.clear(); # remove all entries in dict
    del dict ; # delete entire dictionary

Source:

  1. https://technet.microsoft.com/en-us/library/ee692803.aspx
  2. http://www.cs.mcgill.ca/~abatko/computers/programming/perl/howto/hash/
  3. http://www.tutorialspoint.com/python/python_dictionary.htm

reverse a string on Linux and Windows

How to reverse a string on Linux and Windows

Via shell script on Linux

reverse a string on Linux and Windows

sh-3.2# vi reverse.sh
#### Start Script #####
#!/bin/bash
input_string=”$1″
reverse_string=””

input_string_length=${#input_string}
for (( i=$input_string_length-1; i>=0; i– ))
do
reverse_string=”$reverse_string${input_string:$i:1}”
done

echo “$reverse_string”
##### End Script #####

Let’s run it:

sh-3.2# chmod 775 reverse.sh
sh-3.2# ./reverse.sh Etienne
enneitE

Via powershell script on Windows

#Let’s use the script reverse.ps1 below.
######
$string=”Etienne”
$string_array=$string -split “”
[array]::Reverse($string_array)
$string_array -join ”

#####Output#####
PS C:\Users\etienne_noumen\Documents\Etienne\Scripting> .\reverse.ps1

E t i e n n e

enneitE

Via powershell script on Windows in one line

([regex]::Matches($String,’.’,’RightToLeft’) | ForEach {$_.value}) -join ”

Via batch script on Windows

::Note: ReverseStr also calls StrLen
::and string length is not greater than 80 chars
:: but can be changed.

@echo off
SetLocal EnableDelayedExpansion
cls
set Str=Etienne
call :StrLen %Str%
echo Length=%Len%
call :ReverseStr %Str%
echo String=%Str%
echo Reverse Str=%Reverse%
exit /b

::—————-
:: Calc Var Length
::—————-
:: %*=Str to Check
:: Returns %Len%
:: —————
:StrLen %*
set Data=%*
for /L %%a in (0,1,80) do (
set Char=!Data:~%%a,1!
if not “!Char!”==”” (
set /a Len=%%a+1
) else (exit /b)
)
exit /b

::—————
:: Reverse String
::—————
:: %* Str to Reverse
:: Returns %Reverse%
::——————
:ReverseStr %*
set Data=%*
call :StrLen %Data%
for /L %%a in (!Len!,-1,0) do (
set Char=!Data:~%%a,1!
set Reverse=!Reverse!!Char!
)
exit /b

Via perl script on Windows or Linux

Via python script on Windows or Linux

def reverse_string(a_string)
return a_string[::-1]
reverse_string(“etienne”) returns “enneite”
Source:

  1. http://www.computing.net/answers/programming/reverse-a-string-in-dos/26004.html

prompt and read input variables from keyboard

Let’s find how to prompt and read input variables from keyboard while executing a script using shell, perl, python, batch and powershell (windows and Linux)

  • On Linux via shell

    read -p “Enter your name: ” name
    echo “Hi, $name. Let’s be friend!”

  • On Windows via powershell

    $name=read-host “Enter your name:”
    write-host “Hi $name, Let’s be friend!”

  • On Windows via batch

    Set /p Name=”Enter your name:”
    echo “Hi %name%, Let’s be friend!”

  • On Windows or Linux via perl

    print “Enter your name “;
    my $name = ;
    chomp $name; # Get rid of newline character at the end
    print “Hello $name, let’s be friend”;

  • On Windows or Linux via python

    name=input(“Enter your name: “)
    print (“Hello ” + name + ” let’s be friend”)