install: Discover local substitute servers.

* gnu/installer/substitutes.scm: New file.
* gnu/installer/newt/substitutes.scm: New file.
* gnu/local.mk (INSTALLER_MODULES): Add them.
* po/guix/POTFILES.in: Add gnu/installer/newt/substitutes.scm.
* gnu/installer/proxy.scm (with-silent-shepherd): Move to ...
* gnu/installer/utils.scm: ... here.
* gnu/installer/record.scm (<installer>)[substitutes-page]: New field.
* gnu/installer/newt.scm (substitutes-page): New procedure,
(newt-installer): register it.
* gnu/installer.scm (installer-steps): Add "substitutes-page" step.
* gnu/system/install.scm (%installation-services): Add avahi-service-type and
enable substitute server discover in guix-service-type.
[<name-service-switch>]: Set it to %mdns-host-lookup-nss.

1 files changed, 43 insertions, 0 deletions

diff --git a/gnu/installer/newt/substitutes.scm b/gnu/installer/newt/substitutes.scm
new file mode 100644
index 0000000000..938cb1a53b
--- /dev/null
+++ b/gnu/installer/newt/substitutes.scm
@@ -0,0 +1,43 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2020 Mathieu Othacehe <othacehe@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 (gnu installer newt substitutes)
+  #:use-module (gnu installer substitutes)
+  #:use-module (gnu installer utils)
+  #:use-module (guix i18n)
+  #:use-module (newt)
+  #:use-module (ice-9 match)
+  #:export (run-substitutes-page))
+
+(define* (run-substitutes-page)
+  (match (current-clients)
+    (()
+     (case (choice-window
+            (G_ "Substitute server discovery.")
+            (G_ "Enable") (G_ "Disable")
+            (G_ " By turning this option on, you allow Guix to fetch \
+substitutes (pre-built binaries) during installation from servers \
+discovered on your local area network (LAN) in addition to the official \
+server.  This can increase download throughput.
+
+ There are no security risks: only genuine substitutes may be retrieved from \
+those servers.  However, eavesdroppers on your LAN may be able to see what \
+software you are installing."))
+       ((1) (enable-discovery))
+       ((2) (disable-discovery))))
+    (_ #f)))