Mail Rules

A simple IMAP client which continuously applies mail rules to your Inbox. Rules are defined in a file, for example rules.txt.

The language consists of semicolon-delimited rules, each of which is a predicate followed by an action. For example:

if from = "[email protected]" or subject = "Deal!" then move "Archive";

will move any emails from [email protected] or the subject Deal! to your archive.

The predicate is formed of:

• Field equivalence, to = "[email protected]"
• Field regular expression matches, to ~ "@example.com$"
• Boolean operators and, or and not, to ~ "@example.com$" and not to = "[email protected]"
• Parenthesis for grouping

The action can be one of:

• Move the message to a new folder, move "Archive"
• Flag the message, optionally with a custom flag, flag or flag "My Flag"

Regular expressions provide a powerful matching mechanism, for example:

if to ~ "^marketing\+" then move "Marketing";

will move any email sent to custom addresses like [email protected] to the folder Marketing. Likewise the rule:

if from ~ "[@.]llbean.com$" then move "Marketing";

will move any email sent from an llbean.com email addres, or a subdomain of llbean.com (such as [email protected]) to the folder Marketing.

To Do

Possible future features:

• Reload configuration periodically
• Run at least once every x period
• Support reading from mailboxes other than Inbox
  • Support rules that operate on these mailboxes (default to Inbox?)
• Support rules which can use data extracted from the predicate (e.g. regex capture groups can be templated into folder name)

Creds

Use an app-specific password.

Running

To run locally, first install goyacc:

; go install modernc.org/goyacc@latest

Then generate the parser:

go generate ./parse

Then compile and run mailrules:

go run . \
  --host=imap.mail.me.com:993 \
  --username=$(op read op://Personal/mailrules-icloud/username) \
  --password=$(op read op://Personal/mailrules-icloud/password) \
  --rules=rules.txt

To run within a docker image:

; docker build .
; docker run \
  -v $(pwd)/rules.txt:/etc/mailrules/rules.txt \
  sha256:1c2fdd985c6b3fae9e7c5613c249c1f3bfb2c3ae788bfabad3134e9b8ab83e86 \
  --host=imap.mail.me.com:993 \
  --username=$(op read op://Personal/mailrules-icloud/username) \
  --password=$(op read op://Personal/mailrules-icloud/password) \
  --rules=/etc/mailrules/rules.txt

Deploy

1. Create a configmap containing our rules

   ; kubectl create configmap mailrules-rules --from-file=./rules.txt
   

2. Create a secret with login info

   ; kubectl create secret generic mailrules-icloud \
       --from-literal=username=$(op read op://Personal/mailrules-icloud/username) \
       --from-literal=password=$(op read op://Personal/mailrules-icloud/password)
   

3. Run ./deploy to build the image and template the deployment.yaml