This project is broken and has been abandoned.

If you are looking for an alternative (i.e., a daemon / background service to monitor your inbox and trigger an IMAP sync utility whenever new mail arrives), try gnubiff.

Gnubiff’s intended purpose is to provide a GUI widget that lives in the corner of your screen and shows a preview of new emails as they come in. However, you can run it in headless mode and configure it to run whatever command you want when a new incoming message has been detected (e.g., mbsync -a).

You’ll have to launch it in GUI mode at least once to add your IMAP credentials, and then manually edit the config file to tell it how to fetch your mail:

<!-- ~/.gnubiffrc -->

<configuration-file>
  <general>
    <parameter name="newmail_command" value="pgrep mbsync >/dev/null || mbsync --verbose --all > /home/rlue/log/mbsync.log" />
  </general>
</configuration-file>

Note: If your mail fetching utility invokes a password manager like pass to avoid storing passwords in plain text, you might have to set some environment variables at the start of the newmail_command above, like:

value="export GNUPGHOME='/home/rlue/.config/gnupg'; export PASSWORD_STORE_DIR='/home/rlue/.config/pass'; pgrep ..."

Then, you can set it up and launch it as a systemd service:

# ~/.local/share/systemd/user/gnubiff.service

[Unit]
Description=Gnubiff Headless Email Fetcher
After=network.target

[Service]
ExecStart=/usr/bin/gnubiff --noconfigure --nogui
Restart=on-failure

[Install]
WantedBy=default.target

$ systemctl --user enable gnubiff
$ systemctl --user start gnubiff

📬 Little Red Flag

Sync IMAP mail to your machine. Automatically, instantly, all the time.

Requires isync.

isync (mbsync) is a command-line tool for synchronizing IMAP and local Maildir mailboxes. It’s faster and stabler than the next most popular alternative (OfflineIMAP), but still must be invoked manually. Little Red Flag keeps an eye on your mailboxes and runs the appropriate mbsync command anytime changes occur, whether locally or remotely. It also detects the presence of mu / notmuch mail indexers, and re-indexes after each sync.

Little Red Flag is smart: it only syncs once it’s confirmed that the specified IMAP server is reachable. Remote changes are monitored with IMAP IDLE, and dropped connections are renewed within 60 seconds.

(In fact, it would be ideal if isync implemented this functionality itself, but according to the project maintainer, such plans are vague and indefinitely postponed. If I knew the first thing about C, I’d have taken a stab at improving isync myself; this utility is the next best thing I knew how to make.)

Installation

$ gem install little_red_flag

Usage

Call littleredflag with same arguments you would use for mbsync:

$ littleredflag -a

listens for changes on all remote IMAP folders. Specify one or more channels/groups (as defined in your .mbsyncrc) to watch all IMAP folders contained in them.

You may find it convenient to define a group for all mailboxes you wish to monitor:

# ~/.mbsyncrc
Group inboxes
Channel gmail-inbox
Channel gmail-drafts
Channel gmail-sent
Channel gmail-starred

Then:

$ littleredflag inboxes

Locally, Little Red Flag watches paths specified in MaildirStore sections of your .mbsyncrc, and thus will detect local changes in any mail folder.

Synchronizations are performed only on mail folders where changes are detected. If you’re only monitoring your INBOX, receiving new mail to it will not cause any other folders to sync. (This behavior can be reversed with the -g command line option.)

In .bash_profile

For best results, run Little Red Flag on login.

One way to do that is to add it to your .bash_profile. The following script will launch Little Red Flag idempotently (that is, it will only launch if there is no other instance of Little Red Flag running that was originated by this same script):

mkdir -p "$HOME/tmp"
PIDFILE="$HOME/tmp/littleredflag.pid"

if [ -e "${PIDFILE}" ] && (ps -u $(whoami) -opid= |
                           grep "$(cat ${PIDFILE})" &> /dev/null); then
  :
else
  littleredflag > "$HOME/tmp/littleredflag.log" 2>&1 &

  echo $! > "${PIDFILE}"
  chmod 644 "${PIDFILE}"
fi

Config

Little Red Flag does not accept a configuration dotfile. It extracts the relevant settings from the ~/.mbsyncrc file, and detects mu and notmuch on the basis of their respective dotfiles, as well.

Currently, Little Red Flag only looks for these dotfiles in their default location. Future versions may support a command line option to specify config file locations.

License

The MIT License (MIT)

Copyright © 2017 Ryan Lue