MONGODB_TABLE(5)

NAME
mongodb_table - Postfix MongoDB client configuration

SYNOPSIS
postmap -q "string" mongodb:/etc/postfix/filename

postmap -q - mongodb:/etc/postfix/filename <inputfile

DESCRIPTION
The Postfix mail system uses optional tables for address rewriting or mail routing. These tables are usually in lmdb:, cdb:, hash:, or dbm: format.

Alternatively, lookup tables can be specified as MongoDB databases. To find out what types of lookup tables your Postfix system supports use the "postconf -m" command.

In order to use MongoDB lookups, define a MongoDB source as a lookup table in main.cf, for example:
    alias_maps = mongodb:/etc/postfix/mongodb-aliases.cf

In this example, the file /etc/postfix/mongodb-aliases.cf has the same format as the Postfix main.cf file, and can specify the parameters described below. It is also possible to have the configuration in main.cf; see "OBSOLETE MAIN.CF PARAMETERS" below.

It is strongly recommended to use proxy:mongodb, in order to reduce the number of database connections. For example:
    alias_maps = proxy:mongodb:/etc/postfix/mongodb-aliases.cf

Note: when using proxy:mongodb:/file, the file must be readable by the unprivileged postfix user (specified with the Postfix mail_owner configuration parameter).

MONGODB PARAMETERS

uri The URI of mongo server/cluster that Postfix will try to connect to and query from. Please see
    https://www.mongodb.com/docs/manual/reference/connection-string/

    Example:
        uri = mongodb+srv://user:pass@loclhost:27017/mail

dbname
    Name of the database to read the information from. Example:
        dbname = mail

collection
    Name of the collection (table) to read the information from. Example:
        collection = mailbox

query_filter
    The MongoDB query template used to search the database, where %s is a substitute for the email address that Postfix is trying to resolve. Please see:
    https://www.mongodb.com/docs/manual/tutorial/query-documents/

    Example:
        query_filter = {"$or": [{"username": "%s"}, {"alias.address": "%s"}], "active": 1}

    This parameter supports the following '%' expansions:

    %%  This is replaced by a literal '%' character.

    %s  This is replaced by the input key. The %s must appear in quotes, because all Postfix queries are strings containing (parts from) a domain or email address. Postfix makes no numerical queries.

    %u  When the input key is an address of the form user@domain, %u is replaced by the local part of the address. Otherwise, %u is replaced by the entire search string.

    %d  When the input key is an address of the form user@domain, %d is replaced by the domain part of the address.

    %[1-9]
        The patterns %1, %2, ... %9 are replaced by the corresponding most significant component of the input key's domain. If the input key is user@mail.example.com, then %1 is com, %2 is example and %3 is mail.

    In the above substitutions, characters will be quoted as required by RFC 4627. For example, each double quote or backslash character will be escaped with a backslash characacter.

projection
    Advanced MongoDB query projections. Please see:
    https://www.mongodb.com/docs/manual/tutorial/project-fields-from-query-results/

    •   If projection is non-empty, then result_attribute must be empty.

    •   This implementation can extract information only from result fields that have type string (UTF8), integer (int32, int64) and array. Other result fields will be ignored with a warning. Please see:
        https://mongoc.org/libbson/current/bson_type_t.html

    •   As with result_attribute, the top-level _id field (type OID) is automatically removed from projection results.

result_attribute
    Comma or whitespace separated list with the names of fields to be returned in a lookup result.

    •   If result_attribute is non-empty, then projection must be empty.

    •   As with projection, the top-level _id field (type OID) is automatically removed from lookup results.

result_format (default: %s)
    Format template applied to the result from projection or result_attribute. Most commonly used to append (or prepend) text to the result. This parameter supports the following '%' expansions:

    %%  This is replaced by a literal '%' character.

    %s  This is replaced by the value of the result attribute. When result is empty it is skipped.

    %u  When the result attribute value is an address of the form user@domain, %u is replaced by the local part of the address. When the result has an empty localpart it is skipped.

    %d  When a result attribute value is an address of the form user@domain, %d is replaced by the domain part of the attribute value. When the result is unqualified it is skipped.

    %[SUD1-9]
        The upper-case and decimal digit expansions interpolate the parts of the input key rather than the result. Their behavior is identical to that described with query_filter, and in fact because the input key is known in advance, lookups whose key does not contain all the information specified in the result template are suppressed and return no results.

    For example, using "result_format = smtp:[%s]" allows one to use a mailHost attribute as the basis of a transport(5) table. After applying the result format, multiple values are concatenated as comma separated strings. The expansion_limit parameter explained below allows one to restrict the number of values in the result, which is especially useful for maps that should return a single value.

    The default value %s specifies that each attribute value should be used as is.

    NOTE: DO NOT put quotes around the result format! The result is not a JSON string.

domain (default: no domain list)
    This is a list of domain names, paths to files, or "type:table" databases. When specified, only fully qualified search keys with a *non-empty* localpart and a matching domain are eligible for lookup: 'user' lookups, bare domain lookups and "@domain" lookups are not performed. This can significantly reduce the query load on the backend database. Example:
        domain = postfix.org, hash:/etc/postfix/searchdomains

expansion_limit (default: 0)
    A limit on the total number of result elements returned (as a comma separated list) by a lookup against the map. A setting of zero disables the limit. Lookups fail with a temporary error if the limit is exceeded. Setting the limit to 1 ensures that lookups do not return multiple values.

OBSOLETE MAIN.CF PARAMETERS
MongoDB parameters can also be defined in main.cf. Specify as MongoDB source a name that doesn't begin with a slash or a dot. The MongoDB parameters will then be accessible as the name you've given the source in its definition, an underscore, and the name of the parameter. For example, if a map is specified as "mongodb:mongodb_source", the "uri" parameter would be defined in main.cf as "mongodb_source_uri".

Note: with this form, passwords are written in main.cf, which is normally world-readable, and '$' in a mongodb parameter setting needs to be written as '$$'.

SEE ALSO
postmap(1), Postfix lookup table maintenance
postconf(5), configuration parameters

README FILES
Use "postconf readme_directory" or "postconf html_directory" to locate this information.
DATABASE_README, Postfix lookup table overview
MONGODB_README, Postfix MONGODB client guide

LICENSE
The Secure Mailer license must be distributed with this software.

HISTORY
MongoDB support was introduced with Postfix version 3.9.

AUTHOR(S)
Hamid Maadani (hamid@dexo.tech)
Dextrous Technologies, LLC

Edited by:
Wietse Venema
porcupine.org

Based on prior work by:
Stephan Ferraro
Aionda GmbH