Docker Mailbox Sync

A Docker container which runs the mbsync tool automatically to synchronize your email.

Setup

Select and create two directories:

The "mail" directory where email will be stored. (From now on referred to as /path/to/mail)
The "config" directory where your configuration file will be stored. (From now on referred to as /path/to/config)

Config

In /path/to/config, create a file mbsync.rc for configuration. See the mbsync documentation for the syntax of this file.

The examples in this README mount the destination /path/to/mail directory as /mail inside of the container. If you are going to follow that, you should use /mail as the path in your configuration.

Here is an example, minimal configuration for synchronizing everything in a mailbox:

IMAPAccount example
Host imap.example.com
User me@example.com
Pass abc123
AuthMechs LOGIN
SSLType IMAPS
PipelineDepth 50

IMAPStore example-remote
Account example

MaildirStore example-local
Path /mail/
Inbox /mail/Inbox
SubFolders Verbatim

Channel example
Master :example-remote:
Slave :example-local:
Patterns *
Create Slave
Expunge Slave
SyncState *
Sync Pull

Initial Sync

The first time this container runs, it will download all of your historical emails.

It is not required, but if you'd like to run this sync manually you can choose to do so. This allows you to temporarily interrupt it at any point and also restart if it gets stuck.

$ docker run -it --rm
    -v /path/to/config:/config \
    -v /path/to/mail:/mail \
    jakewharton/mbsync:1 \
    /app/sync.sh

This will run until all emails have been downloaded. At this point, you should set it up to run automatically on a schedule.

Running Automatically

To run the sync automatically on a schedule, pass a valid cron specifier as the CRON environment variable.

$ docker run -it --rm
    -v /path/to/config:/config \
    -v /path/to/mail:/mail \
    -e "CRON=0 * * * *" \
    jakewharton/mbsync:1

The above version will run every hour and download any new emails. For help creating a valid cron specifier, visit cron.help.

To be notified when sync is failing visit https://healthchecks.io, create a check, and specify the ID to the container using the HEALTHCHECK_ID environment variable.

Because the sync can occasionally fail, it's best to set a grace period on the check which is a multiple of your cron period. For example, if you run sync hourly give a grace period of two hours.

To write data as a particular user, the PUID and PGID environment variables can be set to your user ID and group ID, respectively.

Docker Compose

version: '2'
services:
  mbsync:
    image: jakewharton/mbsync:1
    restart: unless-stopped
    volumes:
      - /path/to/config:/config
      - /path/to/mail:/mail
    environment:
      - "CRON=0 * * * *"
      #Optional:
      - "HEALTHCHECK_ID=..."
      - "PUID=..."
      - "PGID=..."

See https://hub.docker.com/r/jakewharton/mbsync/tags for other tags.

LICENSE

MIT. See LICENSE.txt.

Copyright 2020 Jake Wharton

JakeWharton/docker-mbsync