;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2018 Christopher Baines <mail@cbaines.net>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.

(define-module (gnu services message-broker)
  #:use-module (gnu services)
  #:use-module (gnu services shepherd)
  #:use-module (gnu system shadow)
  #:use-module (gnu packages admin)
  #:use-module ((gnu packages base) #:select (glibc-utf8-locales))
  #:use-module (gnu packages rabbitmq)
  #:use-module (guix modules)
  #:use-module (guix records)
  #:use-module (guix gexp)
  #:use-module (ice-9 match)
  #:export (<rabbitmq-configuration>
            rabbitmq-configuration
            rabbitmq-configuration?
            rabbitmq-configuration-rabbitmq
            rabbitmq-configuration-locale
            rabbitmq-configuration-interfaces
            rabbitmq-configuration-tcp-port
            rabbitmq-configuration-udp-port
            rabbitmq-configuration-additional-options

            rabbitmq-service-type))


;;;
;;; RabbitMQ
;;;

(define-record-type* <rabbitmq-configuration>
  rabbitmq-configuration make-rabbitmq-configuration
  rabbitmq-configuration?
  (rabbitmq           rabbitmq-configuration-rabbitmq ;<package>
                      (default rabbitmq))
  (locale             rabbitmq-configuration-rabbitmq
                      (default "en_US.UTF-8"))
  (interfaces         rabbitmq-configuration-interfaces
                      (default '("0.0.0.0")))
  (tcp-port           rabbitmq-configuration-tcp-port
                      (default 11211))
  (udp-port           rabbitmq-configuration-udp-port
                      (default 11211))
  (additional-options rabbitmq-configuration-additional-options
                      (default '())))

(define %rabbitmq-accounts
  (list (user-group (name "rabbitmq") (system? #t))
        (user-account
         (name "rabbitmq")
         (group "rabbitmq")
         (system? #t)
         (comment "Rabbitmq server user")
         (home-directory "/var/lib/rabbitmq")
         (shell (file-append shadow "/sbin/nologin")))))

(define rabbitmq-activation
  #~(begin
      (use-modules (guix build utils))
      (let ((user (getpwnam "rabbitmq")))
        (mkdir-p "/var/run/rabbitmq")
        (chown "/var/run/rabbitmq"
               (passwd:uid user) (passwd:gid user)))))

(define rabbitmq-shepherd-service
  (match-lambda
    (($ <rabbitmq-configuration> rabbitmq locale interfaces tcp-port udp-port
                                 additional-options)
     (with-imported-modules (source-module-closure
                             '((gnu build shepherd)))
       (list (shepherd-service
              (provision '(rabbitmq))
              (documentation "Run the Rabbitmq daemon.")
              (requirement '(user-processes loopback))
              (modules '((gnu build shepherd)))
              (start #~(make-forkexec-constructor
                        '(#$(file-append rabbitmq "/sbin/rabbitmq-server"))
                        #:pid-file "/var/run/rabbitmq/pid"
                        #:environment-variables
                        `("RABBITMQ_PID_FILE=/var/run/rabbitmq/pid"
                          "HOME=/var/lib/rabbitmq"
                          ;; Elixir, the language used by RabbitMQ requires a
                          ;; UTF8 locale to function properly
                          ,(string-append "GUIX_LOCPATH="
                                          #$glibc-utf8-locales "/lib/locale")
                          ,#$(string-append "LC_ALL=" locale))))
              (stop #~(make-kill-destructor))))))))

(define rabbitmq-service-type
  (service-type (name 'rabbitmq)
                (extensions
                 (list (service-extension shepherd-root-service-type
                                          rabbitmq-shepherd-service)
                       (service-extension activation-service-type
                                          (const rabbitmq-activation))
                       (service-extension account-service-type
                                          (const %rabbitmq-accounts))))
                (default-value (rabbitmq-configuration))))