About

This image runs imapfilter, a tool for email filtering. It serves similar purposes as Sieve, but no server-side support is required.

NOTE: Originally based on a fork of https://github.com/eikendev/imapfilter-docker

Running the image

Create a directory to put your imapfilter config in. Since the configuration might have passwords, you should apply appropriate permissions on it restricting it to a specific uid.

$ docker run  --rm --init  --user 1025:1025  --name=imapfilter \
              -v /etc/imapfilter:/config \
              -e IMAPFILTER_CONFIG=/config/config.lua \
              ghcr.io/sandipb/imapfilter
Running: /usr/bin/imapfilter -c /config/config.lua
...

The behavior of imapfilter can be customized by setting the following environment variables:

• IMAPFILTER_CONFIG_DIR: If this is provided and IMAPFILTER_CONFIG is not provided, then imapfilter will look for the config file ${IMAPFILTER_CONFIG_DIR}/.imapfilter/config.lua. This will also set the environment variable IMAPFILTER_HOME to this value.

• IMAPFILTER_CONFIG: Path to the config file. Usually this is the minimum environment variable you need to set. Make sure this path is readable by the userid the docker runs with (default 2000:2000)

• IMAPFILTER_VERBOSE: Adds -v parameter to imapfilter causing the imap protocol details to be dumped to stdout.

• IMAPFILTER_DEBUG_FILE: Path to a file where debug information will be dumped. Adds the -d DEBUGFILE parameter to imapfilter invocation.

• IMAPFILTER_DRY_RUN: Run imapfilter in dry-run mode (parameter -n).

• IMAPFILTER_LOG_DIR: Path to a directory where the imapfilter process will write its stdout and stderr output. Specifically, in ${IMAPFILTER_LOG_DIR}/imapfilter-stdout.log and ${IMAPFILTER_LOG_DIR}/imapfilter-errors.log respectively.

  Note: When using this feature, it is best to mount a tmpfs filesystem on /tmp by passing the parameter --tmpfs /tmp to docker run. This avoids reusing tmp space in the container across invocations and possible clash of temporary files.

• IMAPFILTER_EXTRA_ARGS: Any extra parameters that you would like to add to the imapfilter invocation.

imapfilter resources

These are some resources I found useful for writing imapfilter rules:

• imapfilter configuration man page: https://linux.die.net/man/5/imapfilter_config
• Official imapfilter sample recipes: https://github.com/lefcha/imapfilter/tree/master/samples
• https://moiristo.wordpress.com/2008/11/18/sorting-imap-mail-with-imapfilter/
• https://www.npcglib.org/~stathis/blog/2012/07/09/linux-task-sorting-mail-with-imapfilter/
• https://raymii.org/s/blog/Filtering_IMAP_mail_with_imapfilter.html
• https://ineed.coffee/Old+Posts/Imapfilter+for+remote+rules+to+an+IMAP