Send email messages from local /var/mail spool folder to IMAP folder (on GMail) avoiding all spam filtering. Script user must have "mail" group.

imapdrop.py

import imaplib
import logging
import mailbox
import netrc
import getpass

from datetime import datetime, timezone

logging.basicConfig(level=logging.DEBUG)

# Find GMail login and password in .netrc
M = imaplib.IMAP4_SSL(host="imap.gmail.com", timeout=10)
login, _, password = netrc.netrc().authenticators("imap.gmail.com")

# Take messages from normal local mailbox
mbox = mailbox.mbox("/var/mail/" + getpass.getuser())

M.login(login, password)
M.select()

try:
    for msg in mbox.keys():
        # Append the message as raw bytes to GMail
        # inbox via IMAP
        M.append(
            "INBOX", 
            "", 
            datetime.now(timezone.utc), 
            message=mbox.get_bytes(msg),
        )
        # And remove it from local mbox
        mbox.remove(msg)
finally:
    # Unlocks and flushes the mailbox
    mbox.close()
    M.close()
    M.logout()