Take another stab at this whole guix deploy thing.

Makefile.am

@@ -250,6 +250,7 @@ MODULES =					\
   guix/scripts/weather.scm			\
   guix/scripts/container.scm			\
   guix/scripts/container/exec.scm		\
+  guix/scripts/deploy.scm			\
   guix.scm					\
   $(GNU_SYSTEM_MODULES)
 

gnu/local.mk

@@ -545,6 +545,7 @@ GNU_SYSTEM_MODULES =				\
   %D%/system/shadow.scm				\
   %D%/system/uuid.scm				\
   %D%/system/vm.scm				\
+  %D%/machine.scm			\
 						\
   %D%/build/accounts.scm			\
   %D%/build/activation.scm			\

gnu/machine.scm

@@ -0,0 +1,59 @@
+(define-module (gnu machine)
+  #:use-module ((gnu packages package-management) #:select (guix))
+  #:use-module (gnu system)
+  #:use-module (guix derivations)
+  #:use-module (guix inferior)
+  #:use-module (guix packages)
+  #:use-module (guix ssh)
+  #:use-module (guix store)
+  #:use-module (oop goops)
+  #:use-module (ssh session)
+  #:export (<machine>
+            system
+            display-name
+            build-os
+            deploy-os
+            remote-eval
+
+            <sshable-machine>
+            host-name
+            ssh-port
+            ssh-user))
+
+(define-class <machine> ()
+  (system #:getter system #:init-keyword #:system))
+
+(define-method (display-name (machine <machine>))
+  (operating-system-host-name (system machine)))
+
+(define-method (build-os (machine <machine>) store)
+  (let* ((guixdrv (run-with-store store (package->derivation guix)))
+         (guixdir (and (build-derivations store (list guixdrv))
+                       (derivation->output-path guixdrv)))
+         (osdrv (run-with-store store (operating-system-derivation
+                                       (system machine)))))
+    (and (build-derivations store (list osdrv))
+         (list (derivation-file-name osdrv)
+               (derivation->output-path osdrv)))))
+
+(define-method (deploy-os (machine <machine>) store osdrv)
+  (error "not implemented"))
+
+(define-method (remote-eval (machine <machine>) exp)
+  (error "not implemented"))
+
+(define-class <sshable-machine> (<machine>)
+  (host-name #:getter host-name #:init-keyword #:host-name)
+  (ssh-port #:getter ssh-port #:init-keyword #:ssh-port #:init-form 22)
+  (ssh-user #:getter ssh-user #:init-keyword #:ssh-user #:init-form "root")
+  ;; ??? - SSH key config?
+  )
+
+(define-method (deploy-os (machine <sshable-machine>) store osdrvs)
+  (let ((session (open-ssh-session (host-name machine)
+                                   #:user (ssh-user machine)
+                                   #:port (ssh-port machine))))
+    (with-store store (send-files store osdrvs
+                                  (connect-to-remote-daemon session)
+                                  #:recursive? #t))
+    #t))

guix/scripts/deploy.scm

@@ -0,0 +1,76 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2019 David Thompson <davet@gnu.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 (guix scripts deploy)
+  #:use-module (gnu machine)
+  #:use-module (guix ui)
+  #:use-module (guix scripts)
+  #:use-module (guix scripts build)
+  #:use-module (guix store)
+  #:use-module (ice-9 format)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-37)
+  #:export (guix-deploy))
+
+(define (show-help)
+  (display (G_ "Usage: guix deploy WHATEVER\n")))
+
+(define %options
+  (cons* (option '(#\h "help") #f #f
+                 (lambda args
+                   (show-help)
+                   (exit 0)))
+         %standard-build-options))
+
+(define %default-options
+  '((system . ,(%current-system))
+    (substitutes? . #t)
+    (build-hook? . #t)
+    (graft? . #t)
+    (print-build-trace? . #t)
+    (print-extended-build-trace? . #t)
+    (multiplexed-build-output? . #t)
+    (debug . 0)
+    (verbosity . 2)))
+
+(define (load-source-file file)
+  (let ((module (make-user-module '())))
+    (load* file module)))
+
+(define (guix-deploy . args)
+  (define (handle-argument arg result)
+    (alist-cons 'file arg result))
+  (let* ((opts (parse-command-line args %options (list %default-options)
+                                   #:argument-handler handle-argument))
+         (file (assq-ref opts 'file))
+         (machines (load-source-file file)))
+    (with-store store
+      (set-build-options-from-command-line store opts)
+      ;; Build all the OSes and create a mapping from machine to OS derivation
+      ;; for use in the deploy step.
+      (let ((osdrvs (map (lambda (machine)
+                           (format #t "building ~a... " (display-name machine))
+                           (let ((osdrv (build-os machine store)))
+                             (display "done\n")
+                             (cons machine osdrv)))
+                         machines)))
+        (for-each (lambda (machine)
+                    (format #t "deploying to ~a... " (display-name machine))
+                    (deploy-os machine store (assq-ref osdrvs machine))
+                    (display "done\n"))
+                  machines)))))