Fetch email from S3 bucket written to by SES "receive email" feature

fetch_email.py

#!/usr/bin/env python3
import os
import subprocess
import json
import glob
from pathlib import Path

RCLONE_REMOTE = 'my-s3-remote'
S3_BUCKET = 'my-ses-email-bucket'
RCLONE_REMOTE_S3 = f'{RCLONE_REMOTE}:{S3_BUCKET}'
MAILDIR = Path.home() / 'maildir'
MAILDIR_TMP = MAILDIR / 'tmp'
MAILDIR_NEW = MAILDIR / 'new'
MAILDIR_CUR = MAILDIR / 'cur'


def list_emails():
    p = subprocess.run(['rclone', 'lsjson', RCLONE_REMOTE_S3], capture_output=True, encoding='utf-8')
    emails = json.loads(p.stdout.strip())
    print('fetched emails:', len(emails))
    imported = 0
    for email in emails:
        if email['IsDir']:
            continue
        n = email['Name']
        p = email['Path']
        mod_raw = email['ModTime']
        mod = mod_raw[:19].replace(':', '-')
        ha = n[:10]
        f_base = f'{mod}-{ha}'
        f = f'{f_base}:2,'
        g = glob.glob(f'{MAILDIR_CUR}/{f_base}*')
        if len(g) == 0:
            print('download from S3 ...')
            os.system(f'rclone copyto {RCLONE_REMOTE_S3}/{p} {MAILDIR_TMP}/{f}')
            print('atomic rename ...')
            os.rename(f'{MAILDIR_TMP}/{f}', f'{MAILDIR_CUR}/{f}')
            imported += 1
        else:
            print(f'email already imported: {f_base}')
        # Delete regardless of whether the email was already imported, in case the process was interrupted last time
        print('delete email from S3 ...')
        shell(f'{RCLONE_BIN} --config {RCLONE_CONF} delete {RCLONE_REMOTE_S3}/{p}')

    print('emails imported:', imported)
    print(f'open using command: mutt -f {MAILDIR}')


if __name__ == '__main__':
    list_emails()