From e765cc1ed217c063766f0f3abf0112edb432df3d Mon Sep 17 00:00:00 2001
From: Martin Mares <mj@ucw.cz>
Date: Mon, 31 Oct 2011 14:47:54 +0100
Subject: [PATCH] Updates of job status are atomic

---
 TODO             | 2 --
 lib/BEX/Queue.pm | 3 ++-
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/TODO b/TODO
index 637c805..e6fca02 100644
--- a/TODO
+++ b/TODO
@@ -3,5 +3,3 @@
 - bprun --curses
 - Terminology: machine vs. host
 - Detector of orphans (unused queue dirs, jobs on non-existent machines, non-queued jobs)
-- job failed => give a more explanatory message
-- write_job_status should be atomic
diff --git a/lib/BEX/Queue.pm b/lib/BEX/Queue.pm
index 84e8590..355f649 100644
--- a/lib/BEX/Queue.pm
+++ b/lib/BEX/Queue.pm
@@ -151,11 +151,12 @@ sub read_job_status($$$) {
 sub write_job_status($$$$) {
 	my ($queue, $machine, $jid, $stat) = @_;
 	my $sf = $queue->status_file($machine, $jid);
-	open S, '>', $sf or die "Cannot create $sf: $!";
+	open S, '>', "$sf.$$" or die "Cannot create $sf.$$: $!";
 	for my $k (sort keys %$stat) {
 		print S "$k: ", $stat->{$k}, "\n" if defined $stat->{$k};
 	}
 	close S;
+	rename "$sf.$$", $sf or die "Cannot rename $sf.$$ to $sf: $!";
 }
 
 sub lock_name($$$) {
-- 
2.39.2