From: Eric Wong <e@80x24.org>
To: meta@public-inbox.org
Subject: [PATCH 8/9] emergency: implement new emergency Maildir delivery
Date: Wed, 15 Jun 2016 00:37:41 +0000 [thread overview]
Message-ID: <20160615003742.22538-9-e@80x24.org> (raw)
In-Reply-To: <20160615003742.22538-1-e@80x24.org>
This is transactional and hopefully safer in case we hit SIGSEGV
or SIGKILL during processing, as the tmp/ copy will remain on
the FS even if DESTROY/END handlers are not called.
---
lib/PublicInbox/Emergency.pm | 96 ++++++++++++++++++++++++++++++++++++++++++++
t/emergency.t | 53 ++++++++++++++++++++++++
2 files changed, 149 insertions(+)
create mode 100644 lib/PublicInbox/Emergency.pm
create mode 100644 t/emergency.t
diff --git a/lib/PublicInbox/Emergency.pm b/lib/PublicInbox/Emergency.pm
new file mode 100644
index 0000000..e402d30
--- /dev/null
+++ b/lib/PublicInbox/Emergency.pm
@@ -0,0 +1,96 @@
+# Copyright (C) 2016 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+#
+# Emergency Maildir delivery for MDA
+package PublicInbox::Emergency;
+use strict;
+use warnings;
+use Fcntl qw(:DEFAULT SEEK_SET);
+use Sys::Hostname qw(hostname);
+use IO::Handle;
+
+sub new {
+ my ($class, $dir) = @_;
+
+ foreach (qw(new tmp cur)) {
+ my $d = "$dir/$_";
+ next if -d $d;
+ require File::Path;
+ File::Path::mkpath($d); # croaks on fatal errors
+ }
+ bless { dir => $dir, files => {}, t => 0, cnt => 0 }, $class;
+}
+
+sub _fn_in {
+ my ($self, $dir) = @_;
+ my @host = split(/\./, hostname);
+ my $now = time;
+ if ($self->{t} != $now) {
+ $self->{t} = $now;
+ $self->{cnt} = 0;
+ } else {
+ $self->{cnt}++;
+ }
+
+ my $f;
+ do {
+ $f = "$self->{dir}/$dir/$self->{t}.$$"."_$self->{cnt}.$host[0]";
+ $self->{cnt}++;
+ } while (-e $f);
+ $f;
+}
+
+sub prepare {
+ my ($self, $strref) = @_;
+
+ die "already in transaction: $self->{tmp}" if $self->{tmp};
+ my ($tmp, $fh);
+ do {
+ $tmp = _fn_in($self, 'tmp');
+ $! = undef;
+ } while (!sysopen($fh, $tmp, O_CREAT|O_EXCL|O_RDWR) && $!{EEXIST});
+ print $fh $$strref or die "write failed: $!";
+ $fh->flush or die "flush failed: $!";
+ $fh->autoflush(1);
+ $self->{fh} = $fh;
+ $self->{tmp} = $tmp;
+}
+
+sub abort {
+ my ($self) = @_;
+ delete $self->{fh};
+ my $tmp = delete $self->{tmp} or return;
+
+ unlink($tmp) or warn "Failed to unlink $tmp: $!";
+ undef;
+}
+
+sub fh {
+ my ($self) = @_;
+ my $fh = $self->{fh} or die "{fh} not open!\n";
+ seek($fh, 0, SEEK_SET) or die "seek(fh) failed: $!";
+ sysseek($fh, 0, SEEK_SET) or die "sysseek(fh) failed: $!";
+ $fh;
+}
+
+sub commit {
+ my ($self) = @_;
+
+ delete $self->{fh};
+ my $tmp = delete $self->{tmp} or return;
+ my $new;
+ do {
+ $new = _fn_in($self, 'new');
+ } while (!link($tmp, $new) && $!{EEXIST});
+ my @sn = stat($new) or die "stat $new failed: $!";
+ my @st = stat($tmp) or die "stat $tmp failed: $!";
+ if ($st[0] == $sn[0] && $st[1] == $sn[1]) {
+ unlink($tmp) or warn "Failed to unlink $tmp: $!";
+ } else {
+ warn "stat($new) and stat($tmp) differ";
+ }
+}
+
+sub DESTROY { commit($_[0]) }
+
+1;
diff --git a/t/emergency.t b/t/emergency.t
new file mode 100644
index 0000000..e480338
--- /dev/null
+++ b/t/emergency.t
@@ -0,0 +1,53 @@
+# Copyright (C) 2016 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+use strict;
+use warnings;
+use Test::More;
+use File::Temp qw/tempdir/;
+my $tmpdir = tempdir('emergency-XXXXXX', TMPDIR => 1, CLEANUP => 1);
+use_ok 'PublicInbox::Emergency';
+
+{
+ my $md = "$tmpdir/a";
+ my $em = PublicInbox::Emergency->new($md);
+ ok(-d $md, 'Maildir a auto-created');
+ my @tmp = <$md/tmp/*>;
+ is(scalar @tmp, 0, 'no temporary files exist, yet');
+ $em->prepare(\"BLAH");
+ @tmp = <$md/tmp/*>;
+ is(scalar @tmp, 1, 'globbed one temporary file');
+ open my $fh, '<', $tmp[0] or die "failed to open: $!";
+ is("BLAH", <$fh>, 'wrote contents to temporary location');
+ my @new = <$md/new/*>;
+ is(scalar @new, 0, 'no new files exist, yet');
+ $em = undef;
+ @tmp = <$md/tmp/*>;
+ is(scalar @tmp, 0, 'temporary file no longer exists');
+ @new = <$md/new/*>;
+ is(scalar @new, 1, 'globbed one new file');
+ open $fh, '<', $new[0] or die "failed to open: $!";
+ is("BLAH", <$fh>, 'wrote contents to new location');
+}
+{
+ my $md = "$tmpdir/b";
+ my $em = PublicInbox::Emergency->new($md);
+ ok(-d $md, 'Maildir b auto-created');
+ my @tmp = <$md/tmp/*>;
+ is(scalar @tmp, 0, 'no temporary files exist, yet');
+ $em->prepare(\"BLAH");
+ @tmp = <$md/tmp/*>;
+ is(scalar @tmp, 1, 'globbed one temporary file');
+ open my $fh, '<', $tmp[0] or die "failed to open: $!";
+ is("BLAH", <$fh>, 'wrote contents to temporary location');
+ my @new = <$md/new/*>;
+ is(scalar @new, 0, 'no new files exist, yet');
+ is(sysread($em->fh, my $buf, 9), 4, 'read file handle exposed');
+ is($buf, 'BLAH', 'got expected data');
+ $em->abort;
+ @tmp = <$md/tmp/*>;
+ is(scalar @tmp, 0, 'temporary file no longer exists');
+ @new = <$md/new/*>;
+ is(scalar @new , 0, 'new file no longer exists');
+}
+
+done_testing();
next prev parent reply other threads:[~2016-06-15 0:37 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-15 0:37 [PATCH 0/9] big mda filter changes Eric Wong
2016-06-15 0:37 ` [PATCH 1/9] drop dependency on File::Path::Expand Eric Wong
2016-06-15 0:37 ` [PATCH 2/9] t/feed.t: make IPC::Run usage optional Eric Wong
2016-06-15 0:37 ` [PATCH 3/9] learn: remove IPC::Run dependency Eric Wong
2016-06-15 0:37 ` [PATCH 4/9] t/mda.t: remove senseless use of Email::Filter Eric Wong
2016-06-15 0:37 ` [PATCH 5/9] t/mda: use only Maildir for testing Eric Wong
2016-06-15 0:37 ` [PATCH 6/9] mda: precheck no longer depends on Email::Filter Eric Wong
2016-06-15 0:37 ` [PATCH 7/9] filter: begin work on a new filter API Eric Wong
2016-06-15 0:37 ` Eric Wong [this message]
2016-06-15 0:37 ` [PATCH 9/9] mda: hook up new filter functionality Eric Wong
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