* [PATCH ssoma] extractor: backup state file when updating and fsync
@ 2017-03-21 21:15 Eric Wong
2017-03-21 22:50 ` [PATCH ssoma] extractor: do not needlessly update config file Eric Wong
0 siblings, 1 reply; 2+ messages in thread
From: Eric Wong @ 2017-03-21 21:15 UTC (permalink / raw)
To: meta
The state file is important, so try not to lose it by
creating a backup before git writes it, and fsync the
result ASAP since git does not consider the config file
important enough.
---
| 26 +++++++++++++++++++++++++-
1 file changed, 25 insertions(+), 1 deletion(-)
--git a/lib/Ssoma/Extractor.pm b/lib/Ssoma/Extractor.pm
index afc9afd..7e2b5d1 100644
--- a/lib/Ssoma/Extractor.pm
+++ b/lib/Ssoma/Extractor.pm
@@ -7,6 +7,7 @@ use strict;
use warnings;
use Ssoma::Git;
use Email::LocalDelivery;
+use IO::File;
sub new {
my ($class, $git) = @_;
@@ -106,9 +107,32 @@ sub _extract {
# update the last-imported var
{
+ # This state file is important, and git does not fsync it.
+ if (open my $st, '<', $state) {
+ # clobber existing backup
+ my $bak = "$state.bak";
+ open my $bk, '>', $bak or die
+ "failed to open backup ($bak): $!";
+ my $size = -s $st;
+ my $r = read($st, my $buf, $size);
+ $st->close or die "close $state failed for copy: $!";
+ defined $r or die "failed read $size from $state: $!";
+ $r == $size or die "read ($r != $size) from $state";
+ $bk->write($buf) or die "failed to write $bak: $!";
+ defined($bk->flush) or die "flush $bak failed: $!";
+ defined($bk->sync) or die "fsync $bak failed: $!";
+ $bk->close or die "close $bak failed: $!";
+ }
+
local $ENV{GIT_CONFIG} = $state;
my $rv = system(qw/git config/, $lkey, $tip);
- $rv == 0 or die "git config $lkey $tip failed: $? ($rv)\n";
+ $rv == 0 or die "git config $lkey $tip failed: $? ($rv)";
+
+ # git-config(1) does not fsync state files by default
+ open my $st, '+<', $state or
+ die "failed to open state ($state): $!";
+ defined($st->sync) or die "fsync $state failed: $!";
+ $st->close or die "close $state failed for fsync: $!";
}
}
--
EW
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [PATCH ssoma] extractor: do not needlessly update config file
2017-03-21 21:15 [PATCH ssoma] extractor: backup state file when updating and fsync Eric Wong
@ 2017-03-21 22:50 ` Eric Wong
0 siblings, 0 replies; 2+ messages in thread
From: Eric Wong @ 2017-03-21 22:50 UTC (permalink / raw)
To: meta
No reason to trigger excessive writes when nothing is done.
---
| 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--git a/lib/Ssoma/Extractor.pm b/lib/Ssoma/Extractor.pm
index 7e2b5d1..baf9adb 100644
--- a/lib/Ssoma/Extractor.pm
+++ b/lib/Ssoma/Extractor.pm
@@ -47,6 +47,7 @@ sub _extract {
my $lkey = "target.$target.last-imported";
my $last = $cfg->{$lkey};
+ my $last_imported = $last;
my $ref = $self->{ref};
my $tip = $git->qx_sha1("git rev-parse $ref^0");
@@ -106,7 +107,7 @@ sub _extract {
}
# update the last-imported var
- {
+ if (!defined($last_imported) || $last_imported ne $tip) {
# This state file is important, and git does not fsync it.
if (open my $st, '<', $state) {
# clobber existing backup
--
EW
^ permalink raw reply related [flat|nested] 2+ messages in thread
end of thread, other threads:[~2017-03-21 22:50 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2017-03-21 21:15 [PATCH ssoma] extractor: backup state file when updating and fsync Eric Wong
2017-03-21 22:50 ` [PATCH ssoma] extractor: do not needlessly update config file Eric Wong
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).