如何创建 python 脚本，以便当目录中的 csv 文件在过去 24 小时内未更新时发送 email？

Question

I am new to python and trying to understanding how to automate stuff. I have a folder in which 5 csv files get updated daily, however sometimes one of them or two dont on particular days. Im having to manually check this folder. Instead I want to automate this in such a way that if a csv file does not update in the last 24hours, It can send an email to myself alerting me of this.

My code:

import datetime
import glob
import os
import smtplib
import string
 
now  = datetime.datetime.today() #Get current date

list_of_files = glob.glob('c:/Python/*.csv') # * means all if need specific format then *.csv
latest_file = max(list_of_files, key=os.path.getctime) #get latest file created in folder

newestFileCreationDate = datetime.datetime.utcfromtimestamp(os.path.getctime(latest_file)) # get creation datetime of last file

dif = (now - newestFileCreationDate) #calculating days between actual date and last creation date

logFile = "c:/Python/log.log" #defining a log file

def checkFolder(dif, now, logFile):
    if dif > datetime.timedelta(days = 1): #Check if difference between today and last created file is greater than 1 days
        
        HOST = "12.55.13.12" #This must be your smtp server ip
        SUBJECT = "Alert! At least 1 day wthout a new file in folder xxxxxxx"
        TO = "xx.t@gmail.com"
        FROM = "xx.t@gmail.com"
        text = "%s - The oldest file in folder it's %s old " %(now, dif) 
        BODY = string.join((
            "From: %s" % FROM,
            "To: %s" % TO,
            "Subject: %s" % SUBJECT ,
            "",
            text
            ), "\r\n")
        server = smtplib.SMTP(HOST)
        server.sendmail(FROM, [TO], BODY)
        server.quit()
        
        file = open(logFile,"a") #Open log file in append mode
 
        file.write("%s - [WARNING] The oldest file in folder it's %s old \n" %(now, dif)) #Write a log
 
        file.close() 
        
    else : # If difference between today and last creation file is less than 1 days
                
        file = open(logFile,"a")  #Open log file in append mode
 
        file.write("%s - [OK] The oldest file in folder it's %s old \n" %(now, dif)) #write a log
 
        file.close() 

checkFolder(dif,now,logFile) #Call function and pass 3 arguments defined before
 

However, this does not run without error and I just want to be notified by mail of those files in the folder that havent been updated. even if it is one of out 5 files of them or 5 out of 5 that havent updated.

Answer 1

Use pure python and concise way

import hashlib
import glob
import json
import smtplib
from email.message import EmailMessage
import time
import schedule #pip install schedule
hasher = hashlib.md5()
size = 65536 #to read large files in chunks 
list_of_files = glob.glob('./*.csv') #absolute path for crontab

Part 1) Run this script first then comment it out. It will create a json file with hashes of your files.

first_hashes = {}
for x in list_of_files:

    with open(x, 'rb') as f:
        buf = f.read(size)
        while len(buf) > 0:
            hasher.update(buf)
            buf = f.read(size)
            first_hashes[x] = hasher.hexdigest()

with open('hash.json', 'w') as file:
     file.write(json.dumps(first_hashes, indent=2))

Now comment it out or even delete it.

Part 2) Automation script:

def send_email():


    check_hash = {} #Contain hashes that have not changed
    
    with open('hash.json') as f: #absolute path for crontab
         data = json.load(f)

    for x in list_of_files:

        with open(x, 'rb') as f:
            buf = f.read(size)
            while len(buf) > 0:
                hasher.update(buf)
                buf = f.read(size)
                new_hash = hasher.hexdigest()
                #if a hash match with one in data, that file has not changed
                if new_hash in data.values():
                    check_hash[x] = new_hash
                data[x] = new_hash


    #update our hashes
    with open('hash.json', 'w') as file:  #absolute path for crontab
         file.write(json.dumps(data, indent=2))

    if len(check_hash) > 0: #check if there's anything in check_hash

        filename="check_hash.txt" #absolute path for crontab

        #write to a text file named "check_hash.txt"
        with open(filename, 'w') as f: #absolute path for crontab
            f.write(json.dumps(check_hash, indent=2))

        
        # for gmail smtp setup watch youtu.be/JRCJ6RtE3xU 
        EMAIL_ADDRESS = 'SMTPAddress@gmail.com' 
        EMAIL_PASSWORD = 'SMTPPassWord'

        msg = EmailMessage()

        msg['Subject'] = 'Unupdated files'
        msg['From'] = EMAIL_ADDRESS
        msg['To'] = 'receive@gmail.com'
        msg.set_content('These file(s) did not update:')
        msg.add_attachment(open(filename, "r").read(), filename=filename)



        with smtplib.SMTP_SSL('smtp.gmail.com', 465) as smtp:
            smtp.login(EMAIL_ADDRESS, EMAIL_PASSWORD)
            smtp.send_message(msg)
 

#for faster testing check other options here github.com/dbader/schedule
schedule.every().day.at("10:30").do(send_email) 
while 1:
    schedule.run_pending()
    time.sleep(1)

EDIT: If you restart your pc, you will need to run this file again to restart schedule, to avoid that, you can use crontab as follows (learn how from youtu.be/j-KgGVbyU08):

# mm hh DOM MON DOW command 
30 10 * * *  python3 path-to-file/email-script.py #Linux
30 10 * * *  python path-to-file/email-script.py #Windows

This will run the script everyday at 10:30 AM IF the pc is ON at that time. For faster testing (run every 1 minute) use:

* * * * *  python3 path-to-file/email-script.py

NOTE: If you gonna use crontab, you MUST use absolute path for all file references and replace

schedule.every().day.at("10:30").do(send_email) 
while 1:
    schedule.run_pending()
    time.sleep(1)

with

if __name__ == "__main__":
    send_email()

Tested and it's working great!

Answer 2

Are you thinking of something like this?

import os
from datetime import datetime
import smtplib
import textwrap

def send_email_failure():
    SERVER = "12.55.13.12" #This must be your smtp server ip
    SUBJECT = "Alert! At least 1 day without a new file in folder xxxxxxx"
    TO = "xx.t@gmail.com"
    FROM = "xx.t@gmail.com"
    TEXT = "%s - The oldest file in folder it's %sh old " %(datetime.now(), oldest_time_hour)
    """this is some test documentation in the function"""
    message = textwrap.dedent("""\
        From: %s
        To: %s
        Subject: %s
        %s
        """ % (FROM, ", ".join(TO), SUBJECT, TEXT))
    print(message)
    # Send the mail
    server = smtplib.SMTP(SERVER)
    server.sendmail(FROM, TO, message)
    server.quit()
    

def save_log(logFile, ok_or_failure, time_now, delta):
  file = open(logFile,"a") #Open log file in append mode
  if ok_or_failure != 'ok':
    file.write("%s - [WARNING] The oldest file in folder it's %s old \n" %(time_now, delta)) 
  else:
    file.write("%s - [OK] The oldest file in folder it's %s old \n" %(time_now, delta)) 
  file.close() 



def check_file(filename):
  print(filename)
  if filename.endswith('.csv'):
    print('csv')
    try:
        mtime = os.path.getmtime(filename) # get modified time
    except OSError:
        mtime = 0
    last_modified_date = datetime.fromtimestamp(mtime)
    tdelta = datetime.now() - last_modified_date
    hours =  tdelta.seconds // 3600 # convert to hours
    return hours
  else:
    return 0


# we check what files are in the dir 'files' 
# and their modification time
oldest_time_hour = 0
for path, dirs, files in os.walk('./files'): # this need to be modified by case
  for file in files:
      # get each file time of modification
    time = check_file(path+'/'+file)
    if time > 0:
        # save the oldest time
      if time > oldest_time_hour:
        oldest_time_hour = time
    
# if it is older that 24h
if oldest_time_hour > 24:
  save_log('log.log', 'failure', datetime.now(), oldest_time_hour)
  send_email_failure()
else:
  save_log('log.log', 'ok', datetime.now(), oldest_time_hour)

also you will need an end-less loop to run the python script or a chronjob to run this python script every hour or so

Answer 3

Why are you checking the last_modified_date? I suggest you to check the modification of the file with md5 checksum. My Idea is, if you have following files:

file1.csv
file2.csv
file3.csv
file4.csv
file5.csv

You can check their md5 checksum and write the result + DateTime into a file next to the original file. like following:

file1.csv
file1.csv_checksum

Content of file1.csv_checksum

timestamp,checksum

1612820511,d41d8cd98f00b204e9800998ecf8427e

you can check md5 of a file with following code:

>>> import hashlib
>>> hashlib.md5(open('filename.exe','rb').read()).hexdigest()

then you can check the result with the provided one in the checksum file ( and if the checksum file does not exist, just create it for the first time )

I think you can easily handle it with this approach.

Answer 4

At first i started with a task scheduler decorator which will enable you to poll a directory for a fixed delay:

import time
import functools


def scheduled(fixed_delay):
    def decorator_scheduled(func):
        functools.wraps(func)

        def wrapper_schedule(*args, **kwargs):
            result = func(*args, **kwargs)
            self = args[0]
            delay = getattr(self, fixed_delay)
            time.sleep(delay)
            return result
        return wrapper_schedule
    return decorator_scheduled

Saved it as a seperate module named task_scheduler.py . I will use it in my file watcher:

import os
from task_scheduler import scheduled
import smtplib, ssl

class FileWatcher:
    def __init__(self, 
                 files_path='./myFiles',
                 extension='.csv',
                 poll_delay=2):
        self.files_path = files_path
        self.extension = extension
        self.poll_delay = poll_delay

    def notify_host_on_nonchange(self, file_path):
        port = 465  
        smtp_server = "smtp.gmail.com"
        sender_email = "sender@gmail.com" 
        receiver_email = "receiver@gmail.com"  
        password = "Your password here" #You may want to read it from file 
        message = f"No change in file: {file_path} for 24 hurs!"

        context = ssl.create_default_context()
        with smtplib.SMTP_SSL(smtp_server, port, context=context) as server:
            server.login(sender_email, password)
            server.sendmail(sender_email, receiver_email, message)

    def watch(self):
        try:
            while True:
                self.poll_()
        except KeyboardInterrupt:
            log.debug('Polling interrupted by user.')

    @scheduled("poll_delay")
    def poll_(self,):
        for f in os.listdir(self.files_path):
            full_path = os.path.join(self.files_path, f)
            path_stat = os.stat(full_path)
            _, file_ext = os.path.splitext(f)
            ctime = path_stat.st_ctime
            diff = time.time() - ctime/3600
            if diff<=24 or not S_ISREG(path_stat.st_mode) or str(file_ext) != self.extension:
                continue
            self.notify_host_on_nonchange(full_path)
            


if __name__ == "__main__":
    file_listener = FileWatcher()
    file_listener.watch()

Above class defines a poll_ function which benefits from os.stat module to check the modification time. If modification time smaller than or equal to 24 or the file is not a regular file (means that it is a directory) or it does not have the extension you look for polling will skip it, otherwise calls the notify function to send e-mail. It uses the gmail smtp server example but you can change it as appropriate for your environment. Watch function is a wrapper for continous polling.

This class is adapted from my machine learning model watcher and loader, you can access that version and project from my github . For further explanation about decorator and script you can check out my medium post .

Answer 5

Granted I don't know CSV but I would import time and using the format and time. Sleep function create a timer. What's good about time module is that you can configure it to set a value to a variable after time is up. SO maybe if you do that and put into an if statement, when the variable reaches a value, send the email.