guix/gnu/machine.scm

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;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2019 David Thompson <davet@gnu.org>
;;; Copyright © 2019 Jakob L. Kreuze <zerodaysfordays@sdf.lonestar.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 machine)
#:use-module (gnu system)
#:use-module (guix derivations)
#:use-module (guix monads)
#:use-module (guix records)
#:use-module (guix store)
#:use-module ((guix utils) #:select (source-properties->location))
#:export (environment-type
environment-type?
environment-type-name
environment-type-description
environment-type-location
machine
machine?
this-machine
machine-system
machine-environment
machine-configuration
machine-display-name
deploy-machine
machine-remote-eval))
;;; Commentary:
;;;
;;; This module provides the types used to declare individual machines in a
;;; heterogeneous Guix deployment. The interface allows users of specify system
;;; configurations and the means by which resources should be provisioned on a
;;; per-host basis.
;;;
;;; Code:
;;;
;;; Declarations for resources that can be provisioned.
;;;
(define-record-type* <environment-type> environment-type
make-environment-type
environment-type?
;; Interface to the environment type's deployment code. Each procedure
;; should take the same arguments as the top-level procedure of this file
;; that shares the same name. For example, 'machine-remote-eval' should be
;; of the form '(machine-remote-eval machine exp)'.
(machine-remote-eval environment-type-machine-remote-eval) ; procedure
(deploy-machine environment-type-deploy-machine) ; procedure
;; Metadata.
(name environment-type-name) ; symbol
(description environment-type-description ; string
(default #f))
(location environment-type-location ; <location>
(default (and=> (current-source-location)
source-properties->location))
(innate)))
;;;
;;; Declarations for machines in a deployment.
;;;
(define-record-type* <machine> machine
make-machine
machine?
this-machine
(system machine-system) ; <operating-system>
(environment machine-environment) ; symbol
(configuration machine-configuration ; configuration object
(default #f))) ; specific to environment
(define (machine-display-name machine)
"Return the host-name identifying MACHINE."
(operating-system-host-name (machine-system machine)))
(define (machine-remote-eval machine exp)
"Evaluate EXP, a gexp, on MACHINE. Ensure that all the elements EXP refers to
are built and deployed to MACHINE beforehand."
(let ((environment (machine-environment machine)))
((environment-type-machine-remote-eval environment) machine exp)))
(define (deploy-machine machine)
"Monadic procedure transferring the new system's OS closure to the remote
MACHINE, activating it on MACHINE and switching MACHINE to the new generation."
(let ((environment (machine-environment machine)))
((environment-type-deploy-machine environment) machine)))