PL/ruby

PL/Ruby is a loadable procedural language for the PostgreSQL database system that enables the Ruby language to create functions and trigger procedures.

Prerequisite

ruby 1.8.7 or later

postgresql >= 7.3

All PostgreSQL development headers need to be installed. If you installed using a package manager of some sort, be sure to install the "dev" package.

If you built from source you can run the following command:

    make install-all-headers

Installation

If you're installing the gem:

    gem install postgresql-plruby

If you want to allow the ability to require external libraries:

    gem install postgresql-plruby -- --with-safe-level=0

If you're doing things the old fashioned way:

    ruby extconf.rb
    make
    make install

You may need to specify some of the following extconf.rb options:

    --with-pg-config=<location of the pg_config command of PostgreSQL>

Specifies the location of pg_config. e.g. --with-pg-config=/usr/local/bin/pg_config

    --with-greenplum

Builds plruby for Greenplum instead of PostgreSQL.

    --disable-conversion

By default plruby tries to convert a postgres type to a ruby class. This option gives the possibility to disable all conversions.

   --with-suffix=<suffix to add>

Specifies a suffix to add to the extension module file. e.g. ruby extconf.rb --with-suffix=_geo will create plruby_geo.so.

    --with-safe-level

Lowers the safe level which the plruby functions are run under. (default: 12; meaning the maximum)

    --with-timeout=<seconds>

Sets the timeout for each function call. (default: none)

    --with-main-safe-level

Lowers the safe level which the main thread waiting for timeouts is run under. (default: 3) This option is read only when --with-timeout is given.

Test (and examples)

WARNING: if plruby was compiled without --disable-conversion you must FIRST run make install before make test.

    make test

This will run the following two commands:

    ( cd test/plt; ./runtest )
    ( cd test/plp; ./runtest )

The database plruby_test is created and then destroyed. Don't use it if you have such a database.

Now you are ready to create the PL/Ruby language in PostgreSQL.

Since the pg_language system catalog is private to each database, the new language can be created only for individual databases, or in the template1 database. In the latter case, it is automatically available in all newly created databases.

The commands to create the new language are:

    create function plruby_call_handler () returns language_handler
    as 'path-to-plruby-shared-lib'
    language 'C';

    create trusted language 'plruby'
    handler plruby_call_handler
    lancompiler 'PL/Ruby';

The trusted keyword on create language tells PostgreSQL, that all users (not only those with superuser privilege) are permitted to create functions with LANGUAGE 'plruby'. This is absolutely safe, because there is nothing a normal user can do with PL/Ruby, to get around access restrictions he/she has.

Sample Functions

CREATE FUNCTION ruby_max(int4, int4) RETURNS int4 AS '
   if args[0] > args[1]
       return args[0]
   else
       return args[1]
   end
' LANGUAGE 'plruby';

select ruby_max(1,2);

CREATE FUNCTION ruby_max2(x int4, y int4) RETURNS int4 AS '
   return x > y ? x : y
' LANGUAGE 'plruby';

select ruby_max2(7,8);

Documentation

see plruby.rd and plruby.html

Development

New releases and sources can be obtained from http://github.com/knu/postgresql-plruby

Copying

This extension module is copyrighted free software by Guy Decoux.

You can redistribute it and/or modify it under the same term as Ruby.

Guy Decoux [email protected] (original author, deceased in July 2008) Akinori MUSHA [email protected] (current maintainer)