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imapsql.md

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SQL-indexed storage

The imapsql module implements database for IMAP index and message metadata using SQL-based relational database.

Message contents are stored in an "blob store" defined by msg_store directive. By default this is a file system directory under /var/lib/maddy.

Supported RDBMS:

  • SQLite 3.25.0
  • PostgreSQL 9.6 or newer
  • CockroachDB 20.1.5 or newer

Account names are required to have the form of a email address (unless configured otherwise) and are case-insensitive. UTF-8 names are supported with restrictions defined in the PRECIS UsernameCaseMapped profile.

storage.imapsql {
	driver sqlite3
	dsn imapsql.db
	msg_store fs messages/
}

imapsql module also can be used as a lookup table. It returns empty string values for existing usernames. This might be useful with destination_in directive e.g. to implement catch-all addresses (this is a bad idea to do so, this is just an example):

destination_in &local_mailboxes {
	deliver_to &local_mailboxes
}
destination example.org {
	modify {
		replace_rcpt regexp ".*" "[email protected]"
	}
	deliver_to &local_mailboxes
}

Arguments

Specify the driver and DSN.

Configuration directives

driver string

Required.
Default: not specified

Use a specified driver to communicate with the database. Supported values: sqlite3, postgres.

Should be specified either via an argument or via this directive.

dsn string

Required.
Default: not specified

Data Source Name, the driver-specific value that specifies the database to use.

For SQLite3 this is just a file path. For PostgreSQL: https://godoc.org/github.com/lib/pq#hdr-Connection_String_Parameters

Should be specified either via an argument or via this directive.

msg_store store

Default: fs messages/

Module to use for message bodies storage.

See "Blob storage" section for what you can use here.

compression off
compression algorithm
compression algorithm level

Default: off

Apply compression to message contents. Supported algorithms: lz4, zstd.

appendlimit size

Default: 32M

Don't allow users to add new messages larger than 'size'.

This does not affect messages added when using module as a delivery target. Use max_message_size directive in SMTP endpoint module to restrict it too.

debug boolean

Default: global directive value

Enable verbose logging.

junk_mailbox name

Default: Junk

The folder to put quarantined messages in. Thishis setting is not used if user does have a folder with "Junk" special-use attribute.

disable_recent boolean

Default: true

Disable RFC 3501-conforming handling of \Recent flag.

This significantly improves storage performance when SQLite3 or CockroackDB is used at the cost of confusing clients that use this flag.

sqlite_cache_size integer

Default: defined by SQLite

SQLite page cache size. If positive - specifies amount of pages (1 page - 4 KiB) to keep in cache. If negative - specifies approximate upper bound of cache size in KiB.

sqlite_busy_timeout integer

Default: 5000000

SQLite-specific performance tuning option. Amount of milliseconds to wait before giving up on DB lock.

imap_filter { ... }

Default: not set

Specifies IMAP filters to apply for messages delivered from SMTP pipeline.

Ex.

imap_filter {
	command /etc/maddy/sieve.sh {account_name}
}

delivery_map table

Default: identity

Use specified table module to map recipient addresses from incoming messages to mailbox names.

Normalization algorithm specified in delivery_normalize is appied before delivery_map.

delivery_normalize name

Default: precis_casefold_email

Normalization function to apply to email addresses before mapping them to mailboxes.

See auth_normalize.

auth_map table

Deprecated: Use storage_map in imap config instead.
Default: identity

Use specified table module to map authentication usernames to mailbox names.

Normalization algorithm specified in auth_normalize is applied before auth_map.

auth_normalize name

Deprecated: Use storage_map_normalize in imap config instead.
Default: precis_casefold_email

Normalization function to apply to authentication usernames before mapping them to mailboxes.

Available options:

  • precis_casefold_email PRECIS UsernameCaseMapped profile + U-labels form for domain
  • precis_casefold PRECIS UsernameCaseMapped profile for the entire string
  • precis_email PRECIS UsernameCasePreserved profile + U-labels form for domain
  • precis PRECIS UsernameCasePreserved profile for the entire string
  • casefold Convert to lower case
  • noop Nothing

Note: On message delivery, recipient address is unconditionally normalized using precis_casefold_email function.