Prewarm

import json
from concurrent.futures import ThreadPoolExecutor
import urllib.request
import urllib.error

def warm(Pop,cf_id,cf_url,file_name):
    try:
        file_url = 'http://' + cf_id + '.' + Pop+ '.cloudfront.net' + file_name
        header = {'Host':cf_url}
        req = urllib.request.Request(url=file_url,headers=header)
        response = urllib.request.urlopen(req)
        #print(response)
    except urllib.error.HTTPError as e:
        print('FAILED: ' + 'POP:' + Pop + ' FILE:' + file_url + ' REASON:' + 'HTTPError: {}'.format(e.code))
    except urllib.error.URLError as e:
        print('FAILED: ' + 'POP:' + Pop + ' FILE:' + file_url + ' REASON:' + 'URLError: {}'.format(e.reason))
    except Exception as e:
        print('FAILED: ' + 'POP:' + Pop + ' FILE:' + file_url + ' REASON:' + e)
    else:
        print('SUCCESS: ' + ' POP:' + Pop + ' FILE:' + file_url)

def lambda_handler(event, context):
    # TODO implement
    #print(event)
    #
    #Cloudfront_Url="d1zi40b7x5dwgb.cloudfront.net"
    #Distributions_Id="d1zi40b7x5dwgb"
    #File_Name='/www/a.txt'
    #Cloudfront_Pops = ["EZE51-C1","MEL50-C1","PER50-C1","SYD1-C1"]
    #
    Cloudfront_Pops = ["EZE51-C1","MEL50-C1","PER50-C1","SYD1-C1","SYD1-C2","SYD4-C1","SYD4-C2","VIE50-C1","BAH53-C1","BRU50-C1","GIG51-C2","GRU1-C1","GRU3-C1","GRU50-C1","SOF50-C1","YUL62-C1","YTO50-C1","YTO50-C3","YVR50-C1","SCL50-C1","HKG54-C1","HKG60-C1","HKG62-C1","HKG62-C2","TPE50-C1","TPE51-C1","TPE52-C1","BOG50-C1","ZAG50-C1","PRG50-C1","CPH50-C1","CPH50-C2","HEL50-C1","HEL50-C2","MRS52-C1","CDG3-C2","CDG50-C1","CDG50-C2","TXL52-C1","DUS51-C1","FRA2-C1","FRA2-C2","FRA6-C1","FRA50-C1","FRA56-C1","HAM50-C1","HAM50-C2","HAM50-C3","MUC50-C1","MUC51-C1","ATH50-C1","BUD50-C1","BLR50-C2","MAA50-C1","MAA50-C2","MAA51-C1","MAA51-C2","HYD50-C1","HYD50-C2","HYD50-C3","CCU50-C1","CCU50-C2","BOM50-C1","BOM51-C1","BOM51-C2","BOM52-C1","DEL51-C1","DEL54-C1","DEL54-C3","DUB2-C1","TLV50-C1","MXP64-C1","MXP64-C2","MXP64-C3","PMO50","FCO50-C1","NRT12-C2","NRT12-C3","NRT12-C4","NRT20-C1","NRT20-C2","NRT20-C3","NRT20-C4","NRT51-C1","NRT51-C2","NRT51-C3","NRT51-C4","NRT57-C2","NRT57-C4","NBO50-C1","KUL50-C1","KUL50-C2","QRO50-C1","QRO51-C1","AKL50-C1","OSL50-C1","MNL50-C1","WAW50-C1","LIS50-C1","OTP50-C1","SIN2-C1","SIN5-C1","SIN52-C2","SIN52-C3","CPT50","JNB50","ICN51-C1","ICN51-C2","ICN54-C1","ICN54-C2","ICN54-C3","ICN55-C1","MAD50-C1","MAD51-C2","ARN1-C1","ARN53","ARN54-C1","ZRH50-C1","BKK50-C2","AMS1-C1","AMS50-C1","AMS54-C1","DXB50-C1","FJR50-C1","LHR3-C1","LHR3-C2","LHR52-C1","LHR61-C2","LHR62-C1","LHR62-C3","LHR62-C4","MAN50-C1","MAN50-C3","IAD50-C2","IAD66-C1","IAD66-C2","IAD79-C2","IAD79-C3","IAD89-C1","ATL50-C1","ATL51-C1","ATL56-C1","ATL56-C2","ATL56-C3","BOS50-C1","BOS50-C3","ORD50-C1","ORD51-C2","ORD51-C3","ORD52-C2","ORD53-C1","DFW3-C1","DFW50-C1","DFW53-C1","DFW55-C3","DEN50-C2","DEN52-C1","HIO50-C1","HIO50-C2","HIO51-C1","IAH50-C1","IAH50-C3","IAH50-C4","JAX1-C1","LAX3-C2","LAX3-C4","LAX50-C1","LAX50-C3","MIA3-C1","MIA3-C2","MIA3-C3","MIA3-C5","MSP50-C1","JFK51-C1","EWR50-C1","EWR52-C2","EWR52-C3","EWR52-C4","PHL50-C1","PHX50-C1","PHX50-C2","SLC50-C1","SFO5-C1","SFO5-C3","SFO20-C1","SFO53-C1","SEA19-C1","SEA19-C2","IND6"]
    file = json.dumps(event)
    File_Name = json.loads(file)['filename']
    Cloudfront_Url = json.loads(file)['cloudfront_url']
    Distributions_Id = Cloudfront_Url.split('.')[0]

    with ThreadPoolExecutor(100) as executor:
        for Pop in Cloudfront_Pops:
            try:
                task = executor.submit(warm,Pop,Distributions_Id,Cloudfront_Url,File_Name)
            except Exception as e:
                print(e)