From dcfc6f213b287778b5dc6ea4a8d34f5e1368752b Mon Sep 17 00:00:00 2001
From: Ludovic Courtès <ludo@gnu.org>
Date: Wed, 31 May 2017 15:26:21 +0200
Subject: ui: 'show-what-to-build' warns when we don't have enough disk space.

* guix/ui.scm (check-available-space): New procedure.
(show-what-to-build): Compute 'installed-size' and call
'check-available-space'.
---
 guix/ui.scm | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

(limited to 'guix/ui.scm')

diff --git a/guix/ui.scm b/guix/ui.scm
index 04700a6d20..5060fd6dc7 100644
--- a/guix/ui.scm
+++ b/guix/ui.scm
@@ -38,7 +38,8 @@ (define-module (guix ui)
   #:use-module (guix serialization)
   #:use-module ((guix build utils) #:select (mkdir-p))
   #:use-module ((guix licenses) #:select (license? license-name))
-  #:use-module ((guix build syscalls) #:select (terminal-columns))
+  #:use-module ((guix build syscalls)
+                #:select (free-disk-space terminal-columns))
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-11)
   #:use-module (srfi srfi-19)
@@ -581,6 +582,17 @@ (define (show-derivation-outputs derivation)
                   (derivation->output-path derivation out-name)))
                (derivation-outputs derivation))))
 
+(define (check-available-space need)
+  "Make sure at least NEED bytes are available in the store.  Otherwise emit a
+warning."
+  (let ((free (catch 'system-error
+                (lambda ()
+                  (free-disk-space (%store-prefix)))
+                (const #f))))
+    (when (and free (>= need free))
+      (warning (G_ "at least ~,1h MB needed but only ~,1h MB available in ~a~%")
+               (/ need 1e6) (/ free 1e6) (%store-prefix)))))
+
 (define* (show-what-to-build store drv
                              #:key dry-run? (use-substitutes? #t)
                              (mode (build-mode normal)))
@@ -631,7 +643,9 @@ (define (built-or-substitutable? drv)
                                            substitutable-references
                                            download))))
                      download)))
-    ;; TODO: Show the installed size of DOWNLOAD.
+    (define installed-size
+      (reduce + 0 (map substitutable-nar-size download)))
+
     (define download-size
       (/ (reduce + 0 (map substitutable-download-size download))
          1e6))
@@ -682,6 +696,9 @@ (define display-download-size?
                           (length download))
                       (null? download)
                       (map substitutable-path download)))))
+
+    (check-available-space installed-size)
+
     (pair? build)))
 
 (define show-what-to-build*
-- 
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