[bug#28765] [PATCH] config: Conditionally configure daemon offload script.

[Eric Bavier <ericbavier@centurylink.net>]

On Mon, 09 Oct 2017 23:07:10 +0200
ludo@gnu.org (Ludovic Courtès) wrote:

> Eric Bavier <bavier@cray.com> skribis:
> 
> > From 984e324370c2c17d8d1a982adf2884112c9e64b7 Mon Sep 17 00:00:00 2001
> > From: Eric Bavier <bavier@cray.com>
> > Date: Mon, 9 Oct 2017 13:58:04 -0500
> > Subject: [PATCH] config: Conditionally configure daemon offload script.  
>                    ^
> Nitpick: rather “build:”, which is for all things build-related.
> 
> > * config-daemon.ac (nix/scripts/offload): Configure only if offloading enabled.  
> 
> It LGTM, but is it helpful?  guix-daemon does not invoke ‘guix offload’
> when it’s missing, as can be seen in guix-daemon.cc:
> 
>   #ifdef HAVE_DAEMON_OFFLOAD_HOOK
>         /* Use our build hook for distributed builds by default.  */
>   …

Or maybe something like this would be preferable, to avoid exporting
NIX_BUILD_HOOK if Guix has been configured to disable the daemon
offload hook?

--- a/build-aux/pre-inst-env.in
+++ b/build-aux/pre-inst-env.in
@@ -50,13 +50,9 @@ NIX_LIBEXEC_DIR="@abs_top_builddir@/nix/scripts" # for 'guix-authenticate'
 export NIX_ROOT_FINDER NIX_SUBSTITUTERS NIX_LIBEXEC_DIR
 
 NIX_BUILD_HOOK="$abs_top_builddir/nix/scripts/offload"
-if [ -x "$NIX_BUILD_HOOK" ]
-then
-    export NIX_BUILD_HOOK
-else
-    # No offloading support.
-    unset NIX_BUILD_HOOK
-fi
+@BUILD_DAEMON_OFFLOAD_TRUE@export NIX_BUILD_HOOK
+@BUILD_DAEMON_OFFLOAD_FALSE@# No offloading support.
+@BUILD_DAEMON_OFFLOAD_FALSE@unset NIX_BUILD_HOOK
 
 # The 'guix-register' program.
 GUIX_REGISTER="$abs_top_builddir/guix-register"