;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2019 Jakob L. Kreuze <zerodaysfordays@sdf.org>
;;;
;;; 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 tests reconfigure)
  #:use-module (gnu bootloader)
  #:use-module (gnu services shepherd)
  #:use-module (gnu system)
  #:use-module (gnu system accounts)
  #:use-module (gnu system shadow)
  #:use-module (gnu system vm)
  #:use-module (gnu tests)
  #:use-module (guix derivations)
  #:use-module (guix gexp)
  #:use-module (guix monads)
  #:use-module (guix scripts system reconfigure)
  #:use-module (guix store)
  #:export (%test-switch-to-system
            %test-upgrade-services))

;;; Commentary:
;;;
;;; Test in-place system reconfiguration: advancing the system generation on a
;;; running instance of the Guix System.
;;;
;;; Code:

(define* (run-switch-to-system-test)
  "Run a test of an OS running SWITCH-SYSTEM-PROGRAM, which creates a new
generation of the system profile."
  (define os
    (marionette-operating-system
     (operating-system
       (inherit (simple-operating-system))
       (users (cons (user-account
                     (name "jakob")
                     (group "users")
                     (home-directory "/home/jakob"))
                    %base-user-accounts)))
     #:imported-modules '((gnu services herd)
                          (guix combinators))))

  (define vm (virtual-machine os))

  (define (test script)
    (with-imported-modules '((gnu build marionette))
      #~(begin
          (use-modules (gnu build marionette)
                       (srfi srfi-64))

          (define marionette
            (make-marionette (list #$vm)))

          ;; Return the names of the generation symlinks on MARIONETTE.
          (define (system-generations marionette)
            (marionette-eval
             '(begin
                (use-modules (ice-9 ftw)
                             (srfi srfi-1))
                (let* ((profile-dir "/var/guix/profiles/")
                       (entries (map first (cddr (file-system-tree profile-dir)))))
                  (remove (lambda (entry)
                            (member entry '("per-user" "system")))
                          entries)))
             marionette))

          (test-runner-current (system-test-runner #$output))
          (test-begin "switch-to-system")

          (let ((generations-prior (system-generations marionette)))
            (test-assert "script successfully evaluated"
              (marionette-eval
               '(primitive-load #$script)
               marionette))

            (test-equal "script created new generation"
              (length (system-generations marionette))
              (1+ (length generations-prior)))

            (test-equal "script activated the new generation"
              (string-append "/var/guix/profiles/system-"
                             (number->string (+ 1 (length generations-prior)))
                             "-link")
              (marionette-eval '(readlink "/run/current-system")
                               marionette))

            (test-assert "script activated user accounts"
              (marionette-eval
               '(begin
                  (use-modules (rnrs io ports))
                  (string-contains (call-with-input-file "/etc/passwd"
                                     get-string-all)
                                   "jakob"))
               marionette)))

          (test-end))))

  (gexp->derivation "switch-to-system" (test (switch-system-program os))))

(define* (run-upgrade-services-test)
  "Run a test of an OS running UPGRADE-SERVICES-PROGRAM, which upgrades the
Shepherd (PID 1) by unloading obsolete services and loading new services."
  (define os
    (marionette-operating-system
     (simple-operating-system)
     #:imported-modules '((gnu services herd)
                          (guix combinators))))

  (define vm (virtual-machine os))

  (define dummy-service
    ;; Shepherd service that does nothing, for the sole purpose of ensuring
    ;; that it is properly installed and started by the script.
    (shepherd-service (provision '(dummy))
                      (start #~(const #t))
                      (stop #~(const #t))
                      (respawn? #f)))

  (define (test enable-dummy disable-dummy)
    (with-imported-modules '((gnu build marionette))
      #~(begin
          (use-modules (gnu build marionette)
                       (srfi srfi-64))

          (define marionette
            (make-marionette (list #$vm)))

          ;; Return the names of the running services on MARIONETTE.
          (define (running-services marionette)
            (marionette-eval
             '(begin
                (use-modules (gnu services herd))
                (map live-service-canonical-name (current-services)))
             marionette))

          (test-runner-current (system-test-runner #$output))
          (test-begin "upgrade-services")

          (let ((services-prior (running-services marionette)))
            (test-assert "script successfully evaluated"
              (marionette-eval
               '(primitive-load #$enable-dummy)
               marionette))

            (test-assert "script started new service"
              (and (not (memq 'dummy services-prior))
                   (memq 'dummy (running-services marionette))))

            (test-assert "script successfully evaluated"
              (marionette-eval
               '(primitive-load #$disable-dummy)
               marionette))

            (test-assert "script stopped obsolete service"
              (not (memq 'dummy (running-services marionette)))))

          (test-end))))

  (gexp->derivation
   "upgrade-services"
   (let* ((file (shepherd-service-file dummy-service))
          (enable (upgrade-services-program (list file) '(dummy) '() '()))
          (disable (upgrade-services-program '() '() '(dummy) '())))
     (test enable disable))))

(define %test-switch-to-system
  (system-test
   (name "switch-to-system")
   (description "Create a new generation of the system profile.")
   (value (run-switch-to-system-test))))

(define %test-upgrade-services
  (system-test
   (name "upgrade-services")
   (description "Upgrade the Shepherd by unloading obsolete services and
loading new services.")
   (value (run-upgrade-services-test))))