daemon: Add '--timeout' and '--max-silent-time'.

* nix/nix-daemon/guix-daemon.cc (GUIX_OPT_TIMEOUT)
(GUIX_OPT_MAX_SILENT_TIME): New macros.
* nix/nix-daemon/guix-daemon.cc (options): Add '--timeout' and
'--max-silent-time'.
(parse_opt): Honor them.
* tests/guix-daemon.sh: Add test.
* doc/guix.texi (Invoking guix-daemon): Document the options.
(Common Build Options): Properly describe default
timeout/max-silent-time value.  Add cross-ref to "Invoking
guix-daemon".

doc/guix.texi

@@ -1146,6 +1146,24 @@ Allow at most @var{n} build jobs in parallel.  The default value is
 locally; instead, the daemon will offload builds (@pxref{Daemon Offload
 Setup}), or simply fail.
 
+@item --max-silent-time=@var{seconds}
+When the build or substitution process remains silent for more than
+@var{seconds}, terminate it and report a build failure.
+
+The default value is @code{0}, which disables the timeout.
+
+The value specified here can be overridden by clients (@pxref{Common
+Build Options, @code{--max-silent-time}}).
+
+@item --timeout=@var{seconds}
+Likewise, when the build or substitution process lasts for more than
+@var{seconds}, terminate it and report a build failure.
+
+The default value is @code{0}, which disables the timeout.
+
+The value specified here can be overridden by clients (@pxref{Common
+Build Options, @code{--timeout}}).
+
 @item --rounds=@var{N}
 Build each derivation @var{n} times in a row, and raise an error if
 consecutive build results are not bit-for-bit identical.  Note that this
@@ -4940,12 +4958,15 @@ instead of offloading builds to remote machines.
 When the build or substitution process remains silent for more than
 @var{seconds}, terminate it and report a build failure.
 
+By default, the daemon's setting is honored (@pxref{Invoking
+guix-daemon, @code{--max-silent-time}}).
+
 @item --timeout=@var{seconds}
 Likewise, when the build or substitution process lasts for more than
 @var{seconds}, terminate it and report a build failure.
 
-By default there is no timeout.  This behavior can be restored with
-@code{--timeout=0}.
+By default, the daemon's setting is honored (@pxref{Invoking
+guix-daemon, @code{--timeout}}).
 
 @item --verbosity=@var{level}
 Use the given verbosity level.  @var{level} must be an integer between 0

nix/nix-daemon/guix-daemon.cc

@@ -81,6 +81,8 @@ builds derivations on behalf of its clients.");
 #define GUIX_OPT_GC_KEEP_OUTPUTS 15
 #define GUIX_OPT_GC_KEEP_DERIVATIONS 16
 #define GUIX_OPT_BUILD_ROUNDS 17
+#define GUIX_OPT_TIMEOUT 18
+#define GUIX_OPT_MAX_SILENT_TIME 19
 
 static const struct argp_option options[] =
   {
@@ -91,6 +93,10 @@ static const struct argp_option options[] =
     },
     { "max-jobs", 'M', n_("N"), 0,
       n_("allow at most N build jobs") },
+    { "timeout", GUIX_OPT_TIMEOUT, n_("SECONDS"), 0,
+      n_("mark builds as failed after SECONDS of activity") },
+    { "max-silent-time", GUIX_OPT_MAX_SILENT_TIME, n_("SECONDS"), 0,
+      n_("mark builds as failed after SECONDS of silence") },
     { "disable-chroot", GUIX_OPT_DISABLE_CHROOT, 0, 0,
       n_("disable chroot builds") },
     { "chroot-directory", GUIX_OPT_CHROOT_DIR, n_("DIR"), 0,
@@ -245,6 +251,12 @@ parse_opt (int key, char *arg, struct argp_state *state)
     case 'M':
       settings.set ("build-max-jobs", arg);
       break;
+    case GUIX_OPT_TIMEOUT:
+      settings.set ("build-timeout", arg);
+      break;
+    case GUIX_OPT_MAX_SILENT_TIME:
+      settings.set ("build-max-silent-time", arg);
+      break;
     case GUIX_OPT_SYSTEM:
       settings.thisSystem = arg;
       break;

tests/guix-daemon.sh

@@ -145,3 +145,39 @@ guile -c '
            (exit
             (= 42 (pk (call-with-input-file (derivation->output-path drv)
                         read)))))))'
+
+
+kill "$daemon_pid"
+
+# Make sure the daemon's default 'timeout' and 'max-silent-time' settings are
+# honored.
+
+client_code='
+  (use-modules (guix) (gnu packages) (guix tests) (srfi srfi-34))
+
+  (with-store store
+    (let* ((build  (add-text-to-store store "build.sh"
+                                      "while true ; do : ; done"))
+           (bash   (add-to-store store "bash" #t "sha256"
+                                 (search-bootstrap-binary "bash"
+                                                          (%current-system))))
+           (drv    (derivation store "the-thing" bash
+                               `("-e" ,build)
+                               #:inputs `((,bash) (,build))
+                               #:env-vars `(("x" . ,(random-text))))))
+      (exit (guard (c ((nix-protocol-error? c)
+                       (->bool
+                        (string-contains (pk (nix-protocol-error-message c))
+                                         "failed"))))
+              (build-derivations store (list drv))
+              #f))))'
+
+
+for option in --max-silent-time=1 --timeout=1
+do
+    guix-daemon --listen="$socket" --disable-chroot "$option" &
+    daemon_pid=$!
+
+    GUIX_DAEMON_SOCKET="$socket" guile -c "$client_code"
+    kill "$daemon_pid"
+done