exim2sieve

exim2sieve is a small Go utility that helps you migrate cPanel Exim filters and mailboxes to modern, Sieve‑capable mail platforms such as Mailcow, DirectAdmin, or any other Dovecot/Sieve setup.

It focuses on:

• Exporting cPanel filter definitions (filter.yaml / filter) per mailbox.
• Converting those filters to Sieve scripts with sane names and comments.
• Importing Sieve scripts into the target server via doveadm.
• Optionally exporting & importing full Maildir contents.
• Creating Mailcow mailboxes via API based on the exported backup tree.

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High‑level workflow

Typical migration flow from cPanel → Mailcow / other Dovecot:

1. Export filters (and optionally maildirs) from the cPanel server:

   ./exim2sieve -cpanel-user myipgr -dest ./backup -maildir

2. (Optional) Create mailboxes in Mailcow based on the export tree:

   ./exim2sieve -config exim2sieve.conf      -create-mailcow-mailboxes      -backup ./backup/myipgr      -domain myip.gr

3. Import Sieve into the target Dovecot:

   ./exim2sieve -config exim2sieve.conf      -import-sieve      -backup ./backup/myipgr      -domain myip.gr

4. Import Maildir contents (message migration):

   ./exim2sieve -config exim2sieve.conf      -import-maildir      -backup ./backup/myipgr      -domain myip.gr

You can also work per single mailbox using -mailbox chris or -mailbox [email protected].

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Features (current)

1. cPanel export

• Export all filters for a single cPanel account:
  • Per‑domain _domain.filter + _domain.sieve.
  • Per‑mailbox filter.yaml / filter + converted *.sieve.
• Optional Maildir export for each mailbox.

Command:

./exim2sieve -cpanel-user myipgr -dest ./backup
./exim2sieve -cpanel-user myipgr -dest ./backup -maildir   # include Maildir data

Export layout:

backup/
  myipgr/                     ← cPanel user
    mailcow_mailboxes.log     ← optional log from Mailcow creation step
    myip.gr/                  ← domain
      _domain.filter          ← raw /etc/vfilters/myip.gr (optional)
      _domain.sieve           ← converted domain-wide Sieve (if present)
      chris/
        filter.yaml           ← original cPanel YAML filter
        chris.sieve           ← combined Sieve for this mailbox
        maildir/              ← optional Maildir copy (if -maildir used)
      admin/
        filter.yaml
        admin.sieve
        maildir/
      ...

2. Filter parsing & Sieve conversion

Supported inputs:

• filter.yaml (cPanel YAML filter format).
• Text filter files (cPanel Exim filter syntax).

The internal sieve package:

• Parses cPanel rules into a neutral Filter format.
• Converts each enabled filter entry into a SieveScript.
• Combines multiple rules into a single, clean Sieve script per mailbox using CombineScripts.

Names & comments

• Each Exim filter rule has a filtername (from YAML) or #Name (from text file).
• The combined Sieve script:
  • Deduplicates all require [...] lines and puts them at the top.
  • For each rule, adds:

    # Filter: Nixpal
    if address :is "from" "[email protected]" {
        fileinto "Nixpal";
        stop;
    }

• Roundcube / Sieve UIs often encode rule names as:

  # rule:[Nixpal]

  The converter already preserves human‑readable block labels via # Filter: ....
  You can later extend it to emit # rule:[name] if you want Roundcube‑style naming.

Example YAML → Sieve:

filter:
  -
    enabled: 1
    filtername: Nixpal
    rules:
      - part: "$header_from:"
        match: is
        opt: or
        val: [email protected]
    actions:
      - action: save
        dest: Nixpal
      - action: finish
        dest: ~

Becomes:

require ["fileinto"];

# Filter: Nixpal
if address :is "from" "[email protected]"
{
    fileinto "Nixpal";
    stop;
}

3. Single file conversion mode (-path)

You can convert a single filter.yaml or filter file to Sieve as a quick test or standalone tool:

./exim2sieve -path /home/myipgr/etc/myip.gr/chris/filter.yaml -dest ./out

The tool auto‑detects YAML vs text:

• If it looks like filter.yaml → parse YAML.
• Otherwise → parse text Exim filter.

Output:

out/
  filters.sieve   ← combined Sieve script for that YAML/filter file

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4. Sieve import via doveadm (-import-sieve)

After you have a backup tree (e.g. ./backup/myipgr), you can import Sieve into the target Dovecot using doveadm.

Config (exim2sieve.conf)

Basic example:

[doveadm]
# Bare metal dovecot:
command = doveadm

# Mailcow (dovecot in Docker), e.g.:
# command = docker exec -i mailcowdockerized-dovecot-mailcow-1 doveadm

[mailcow]
# Optional, used only by -create-mailcow-mailboxes mode
api_url = https://mail.example.com
api_key = your-mailcow-api-key
default_quota = 5GB

[paths]
# Optional, for Maildir import mapping (see below)
# maildir_host_base = /root/chris/backup
# maildir_container_base = /backup

Import all Sieve scripts for a domain

./exim2sieve -config exim2sieve.conf   -import-sieve   -backup ./backup/myipgr   -domain myip.gr

What it does:

• Walks ./backup/myipgr/myip.gr/<localpart>/.
• For each mailbox (e.g. chris):
  • Finds chris.sieve (or first *.sieve).
  • Checks if user exists on the target:

    doveadm user -u [email protected]

  • If the user exists:
    • Runs:

      doveadm sieve put -u [email protected] cpanel-migrated < chris.sieve
      doveadm sieve activate -u [email protected] cpanel-migrated

    • Logs:

      Imported sieve for [email protected] from .../chris.sieve as cpanel-migrated
      

Import Sieve for a single mailbox

Use the -mailbox filter:

# by localpart
./exim2sieve -config exim2sieve.conf   -import-sieve   -backup ./backup/myipgr   -domain myip.gr   -mailbox chris

# or full address
./exim2sieve -config exim2sieve.conf   -import-sieve   -backup ./backup/myipgr   -domain myip.gr   -mailbox [email protected]

The importer will match either uname == "chris" or address [email protected].

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5. Maildir export (-maildir) & import (-import-maildir)

Export side (on cPanel)

When you export with -maildir, ExportUser additionally copies each mailbox’s Maildir:

./exim2sieve -cpanel-user myipgr -dest ./backup -maildir

Layout example:

backup/myipgr/myip.gr/chris/
  filter.yaml
  chris.sieve
  maildir/
    cur/
    new/
    tmp/
backup/myipgr/myip.gr/admin/
  filter.yaml
  admin.sieve
  maildir/
    ...

The Maildir copy is a straightforward directory copy (retaining cur/, new/, tmp/).

Import side (on destination Dovecot)

Use -import-maildir:

./exim2sieve -config exim2sieve.conf   -import-maildir   -backup ./backup/myipgr   -domain myip.gr

For each mailbox:

• Verifies that maildir/ exists and looks like Maildir (at least cur/ or new/).

• Checks if the user exists via doveadm user -u addr.

• If yes, runs:

  doveadm import -u addr maildir:/path/to/maildir "" ALL

• Logs:

  Imported maildir for [email protected] from backup/myipgr/myip.gr/chris/maildir
  

Docker‑safe Maildir path mapping

When Dovecot runs inside Docker (e.g. Mailcow), the host path where backups live may not be visible directly.
To handle this, ImportMaildir supports host→container mapping via [paths] config:

[paths]
maildir_host_base = /root/chris/backup
maildir_container_base = /backup

Assuming you mount your backup into the Dovecot container:

# docker-compose override example
dovecot-mailcow:
  volumes:
    - /root/chris/backup:/backup:ro

Then host path:

/root/chris/backup/myipgr/myip.gr/chris/maildir

is automatically mapped to:

/backup/myipgr/myip.gr/chris/maildir

So the actual doveadm command becomes:

doveadm import -u [email protected] maildir:/backup/myipgr/myip.gr/chris/maildir "" ALL

If maildir_host_base / maildir_container_base are empty, the tool simply uses the host path as‑is (good for DirectAdmin / bare metal Dovecot).

You can also limit to a single mailbox:

./exim2sieve -config exim2sieve.conf   -import-maildir   -backup ./backup/myipgr   -domain myip.gr   -mailbox chris

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6. Mailcow mailbox creation (-create-mailcow-mailboxes)

exim2sieve can read the backup tree and create Mailcow mailboxes via API before you import filters/Maildir.

Config

In exim2sieve.conf:

[mailcow]
api_url = https://mail.example.com
api_key = your-mailcow-api-key
default_quota = 10GB   ; mailbox quota (MB/GB syntax supported)

Command

./exim2sieve -config exim2sieve.conf   -create-mailcow-mailboxes   -backup ./backup/myipgr   -domain myip.gr

Behavior:

• Walks ./backup/myipgr/myip.gr/<localpart>/ and builds a mailbox list.
• Uses the Mailcow API client to:
  • Ensure the domain exists (or create it if needed, depending on your Mailcow config/permissions).
  • Create each mailbox with the configured default quota.
• Logs a summary to mailcow_mailboxes.log under backup/myipgr.

You can then run -import-sieve and -import-maildir to attach filters and messages to those mailboxes.

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7. CLI reference (current flags)

exim2sieve is mode‑based: exactly one of the main modes should be active per run.

Main modes

• -cpanel-user <user> / -account <user>
  Export filters (and optionally Maildir) for a cPanel account:

  ./exim2sieve -cpanel-user myipgr -dest ./backup
  ./exim2sieve -cpanel-user myipgr -dest ./backup -maildir

• -path <file>
  Convert a single filter.yaml or filter to filters.sieve in -dest.

• -import-sieve
  Import Sieve scripts from a backup using doveadm.

• -import-maildir
  Import Maildir contents from a backup using doveadm import.

• -create-mailcow-mailboxes
  Create Mailcow domains/mailboxes from a backup tree via the Mailcow API.

Common flags

• -dest <dir>
  Destination folder for exports (default: ./backup).

• -maildir
  When exporting from cPanel, also copy each mailbox's Maildir under maildir/.

• -backup <path>
  Root of existing backup tree for import modes (e.g. ./backup/myipgr).

• -domain <domain>
  Limit import/export to a specific domain (myip.gr).
  (Useful when an account has many domains.)

• -mailbox <name or full address>
  Limit Sieve/Maildir import to a single mailbox:

  • -mailbox chris
  • -mailbox [email protected]

• -config <file>
  Path to exim2sieve.conf.
  If omitted, the loader will try ./exim2sieve.conf and /etc/exim2sieve.conf.
  Fallback defaults: doveadm in PATH, Mailcow disabled.

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Example scenarios

A. Full migration from cPanel → Mailcow (single account / domain)

On the cPanel server:

./exim2sieve -cpanel-user myipgr -dest /root/chris/backup -maildir
tar czf myipgr-backup.tgz -C /root/chris/backup myipgr

Move myipgr-backup.tgz to the Mailcow host, extract to /root/chris/backup.

On the Mailcow host:

1. Ensure backup is mounted inside Dovecot container:

   dovecot-mailcow:
     volumes:
       - /root/chris/backup:/backup:ro

2. Configure exim2sieve.conf:

   [doveadm]
   command = docker exec -i mailcowdockerized-dovecot-mailcow-1 doveadm
   
   [mailcow]
   api_url = https://mail.example.com
   api_key = your-mailcow-api-key
   default_quota = 10GB
   
   [paths]
   maildir_host_base = /root/chris/backup
   maildir_container_base = /backup

3. Create Mailcow mailboxes:

   ./exim2sieve -config exim2sieve.conf      -create-mailcow-mailboxes      -backup /root/chris/backup/myipgr      -domain myip.gr

4. Import Sieve:

   ./exim2sieve -config exim2sieve.conf      -import-sieve      -backup /root/chris/backup/myipgr      -domain myip.gr

5. Import Maildir:

   ./exim2sieve -config exim2sieve.conf      -import-maildir      -backup /root/chris/backup/myipgr      -domain myip.gr

B. Partial test migration (single mailbox, filters‑only)

./exim2sieve -cpanel-user myipgr -dest ./backup      # on cPanel side
rsync -av ./backup/myipgr mycow:/srv/exim2sieve/     # copy tree

# On target server (with dovecot):
./exim2sieve -config exim2sieve.conf   -import-sieve   -backup /srv/exim2sieve/myipgr   -domain myip.gr   -mailbox chris

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Contributing

Contributions, bug reports and feature ideas are welcome.

• Add support for more complex Exim constructs.
• Improve Sieve rule naming (e.g. Roundcube‑style # rule:[name]).
• Extend import/export helpers for other control panels.

Please open an issue or PR on GitHub with a clear description and, if possible, sample filter.yaml / filter snippets.

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Usage flow

1. Export from cPanel (creates backup + shadow under per-domain dirs): ./exim2sieve -cpanel-user mycpuser -dest ./backup -maildir

→ ./backup/mycpuser//shadow

2. Create mailboxes in Mailcow via API: ./exim2sieve -config exim2sieve.conf
   -create-mailcow-mailboxes
   -backup ./backup/mycpuser
   -domain myip.gr

3. Patch passwords from shadow into Mailcow MySQL: ./exim2sieve -config exim2sieve.conf
   -mailcow-passwords-from-shadow
   -backup ./backup/mycpuser
   -domain myip.gr