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authorEric Wong <e@80x24.org>2016-05-24 03:41:53 +0000
committerEric Wong <e@80x24.org>2016-05-24 04:12:51 +0000
commit64aea34d06f71828b0bdd6ae177b9bcf22d752b4 (patch)
tree4f7df75d112aa4fe0b9056cf24688a2e42032019 /lib/PublicInbox/Qspawn.pm
parent8648f519a95872600689c3a5d6d87fd17770f9fc (diff)
downloadpublic-inbox-64aea34d06f71828b0bdd6ae177b9bcf22d752b4.tar.gz
Having an excessive amount of git-pack-objects processes is
dangerous to the health of the server.  Queue up process spawning
for long-running responses and serve them sequentially, instead.
Diffstat (limited to 'lib/PublicInbox/Qspawn.pm')
-rw-r--r--lib/PublicInbox/Qspawn.pm52
1 files changed, 52 insertions, 0 deletions
diff --git a/lib/PublicInbox/Qspawn.pm b/lib/PublicInbox/Qspawn.pm
new file mode 100644
index 00000000..9e4c8e08
--- /dev/null
+++ b/lib/PublicInbox/Qspawn.pm
@@ -0,0 +1,52 @@
+# Copyright (C) 2016 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+package PublicInbox::Qspawn;
+use strict;
+use warnings;
+use PublicInbox::Spawn qw(popen_rd);
+our $LIMIT = 1;
+my $running = 0;
+my @run_queue;
+
+sub new ($$$;) {
+        my ($class, $cmd, $env, $opt) = @_;
+        bless { args => [ $cmd, $env, $opt ] }, $class;
+}
+
+sub _do_spawn {
+        my ($self, $cb) = @_;
+        my $err;
+        ($self->{rpipe}, $self->{pid}) = popen_rd(@{$self->{args}});
+        if ($self->{pid}) {
+                $running++;
+        } else {
+                $self->{err} = $!;
+        }
+        $cb->($self->{rpipe});
+}
+
+sub finish ($) {
+        my ($self) = @_;
+        if (delete $self->{rpipe}) {
+                my $pid = delete $self->{pid};
+                $self->{err} = $pid == waitpid($pid, 0) ? $? :
+                                "PID:$pid still running?";
+                $running--;
+        }
+        if (my $next = shift @run_queue) {
+                _do_spawn(@$next);
+        }
+        $self->{err};
+}
+
+sub start ($$) {
+        my ($self, $cb) = @_;
+
+        if ($running < $LIMIT) {
+                _do_spawn($self, $cb);
+        } else {
+                push @run_queue, [ $self, $cb ];
+        }
+}
+
+1;