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authorJannis M. Hoffmann <jannis.hoffmann@rwth-aachen.de>2020-11-03 17:01:16 +0100
committerJannis M. Hoffmann <jannis.hoffmann@rwth-aachen.de>2020-11-03 17:01:16 +0100
commit13c68ce71390463f200b02280bf5e064224eb58c (patch)
tree9b37fed30b77173e88855cbbe53776266824cb18
parent2e60e72c0af1e614a96d13df2c5b417733a78d46 (diff)
propper process coordination for session cleanup
-rw-r--r--lib/JWebmail/Plugin/ServerSideSessionData.pm135
1 files changed, 97 insertions, 38 deletions
diff --git a/lib/JWebmail/Plugin/ServerSideSessionData.pm b/lib/JWebmail/Plugin/ServerSideSessionData.pm
index 9890358..e86a248 100644
--- a/lib/JWebmail/Plugin/ServerSideSessionData.pm
+++ b/lib/JWebmail/Plugin/ServerSideSessionData.pm
@@ -1,99 +1,151 @@
-package JWebmail::Plugin::ServerSideSessionData;
+package JWebmail::Plugin::ServerSideSessionData v1.1.0;
use Mojo::Base 'Mojolicious::Plugin';
use Mojo::JSON qw(decode_json encode_json);
use Mojo::File;
-use constant {
- S_KEY => 's3d.key',
-};
+use Fcntl ':DEFAULT', ':seek';
+use Time::HiRes 'sleep';
-has '_session_directory';
-sub session_directory { my $self = shift; @_ ? $self->_session_directory(Mojo::File->new(@_)) : $self->_session_directory }
+use constant S_KEY => 's3d.key';
+use constant CLEANUP_FILE_NAME => 'cleanup';
+use constant LOCK_ITER => 5;
+use constant ADVANCE_ON_FAILURE => 10; # seconds to retry to acquire the lock
+has 'session_directory';
has 'expiration';
has 'cleanup_interval';
-has '_cleanup';
-sub cleanup {
+has 'next_cleanup' => 0;
+
+
+# read und potentially update file return bool
+# needs atomic lock file
+# the file contains a single timestamp
+sub _rw_cleanup_file {
my $self = shift;
- if (@_) {
- return $self->_cleanup(@_);
+ my $time = shift;
+
+ my $lock_name = $self->session_directory->child(CLEANUP_FILE_NAME . ".lock");
+ my $info_name = $self->session_directory->child(CLEANUP_FILE_NAME . ".info");
+
+ my ($lock, $ctr, $rmlock);
+ until (sysopen($lock, $lock_name, O_WRONLY | O_CREAT | O_EXCL)) {
+ die "unexpected error '$!'" unless $! eq 'File exists';
+ if ($ctr > LOCK_ITER) {
+ open($lock, '<', $lock_name) or die "unexpected error '$!'";
+ my $pid = <$lock>;
+ close $lock;
+ chomp $pid;
+ if (!$rmlock && (!$pid || !-e "/proc/$pid")) {
+ $lock_name->remove;
+ $rmlock = 1;
+ next;
+ }
+ $self->next_cleanup($time + ADVANCE_ON_FAILURE);
+ return 0;
+ }
+ sleep(0.01); # TODO: better spin locking
+ } continue {
+ $ctr++;
}
- else {
- if ($self->_cleanup < time) {
+ $lock->say($$);
+ $lock->close;
+
+ my $ret = eval {
+ use autodie;
+
+ open(my $info, -e $info_name ? '+<' : '+>', $info_name);
+ my $next_time = $info->getline;
+ $next_time = 0 unless ($next_time//'') =~ /^\d+$/;
+ chomp $next_time;
+ if ($next_time > $time) {
+ $info->close;
+ $self->next_cleanup($next_time);
return 0;
}
else {
- $self->_cleanup(time + $self->cleanup_interval);
+ $info->truncate(0);
+ $info->seek(0, SEEK_SET);
+ $info->say($time + $self->cleanup_interval);
+ $info->close;
+ $self->next_cleanup($time + $self->cleanup_interval);
return 1;
}
- }
+ };
+ $lock_name->remove;
+ return $ret;
}
-sub s3d {
+sub cleanup_files {
my $self = shift;
- my $c = shift;
- # cleanup old sessions
- if ($self->cleanup) {
- my $t = time;
+ my $t = time;
+ if ($self->next_cleanup < $t && $self->_rw_cleanup_file($t)) {
for ($self->session_directory->list->each) {
if ( $_->stat->mtime + $self->expiration < $t ) {
$_->remove;
}
}
}
+}
+
+
+sub s3d {
+ my $self = shift;
+ my $c = shift;
+ my ($key, $val) = @_;
+
+ # cleanup old sessions
+ $self->cleanup_files;
my $file = $self->session_directory->child($c->session(S_KEY) || $c->req->request_id . $$);
if (-e $file) {
if ($file->stat->mtime + $self->expiration < time) {
- $file->remove;
+ truncate $file, 0;
}
else {
$file->touch;
}
}
- my $data = decode_json($file->slurp) if (-s $file);
+ elsif (defined $val) {
+ $file->touch;
+ $file->chmod(0600);
+ $c->session(S_KEY, $file->basename);
+ }
- my ($key, $val) = @_;
+ my $data = decode_json($file->slurp) if (-s $file);
if (defined $val) { # set
- unless (-e $file) {
- $c->session(S_KEY, $file->basename);
- }
$data = ref $data ? $data : {};
$data->{$key} = $val;
- #$file->spurt(encode_json $data);
- open(my $f, '>', $file) or die "$!";
- chmod 0600, $f;
- $f->say(encode_json $data);
- close($f);
+ $file->spurt(encode_json $data, "\n");
}
else { # get
return defined $key ? $data->{$key} : $data;
}
-};
+}
sub register {
my ($self, $app, $conf) = @_;
- $self->session_directory($conf->{directory} || "/tmp/" . $app->moniker);
+ $self->session_directory(Mojo::File->new($conf->{directory} || "/tmp/" . $app->moniker));
$self->expiration($conf->{expiration} || $app->sessions->default_expiration);
$self->cleanup_interval($conf->{cleanup_interval} || $self->expiration);
- $self->cleanup(time + $self->cleanup_interval);
unless (-d $self->session_directory) {
mkdir($self->session_directory)
or $! ? die "failed to create directory: $!" : 1;
}
+ $self->cleanup_files;
+
$app->helper( s3d => sub { $self->s3d(@_) } );
}
@@ -110,7 +162,7 @@ ServeSideSessionData - Stores session data on the server (alias SSSD or S3D)
=head1 SYNOPSIS
- $app->plugin('ServeSideSessionData');
+ $app->plugin('ServeSideSessionData', {expiration => 20*60});
$c->s3d(data => 'Hello, S3D');
$c->s3d('data');
@@ -118,21 +170,28 @@ ServeSideSessionData - Stores session data on the server (alias SSSD or S3D)
=head1 DESCRIPTION
Store data temporarily on the server.
-The only protetction on the server are struct user access rights.
+The only protection on the server are strict user access rights
+so you need to still be careful with your secrets.
=head1 OPTIONS
=head2 directory
+directory where session data is stored
+
default C<< 'tmp/' . $app->moniker >>
=head2 expiration
-default session expiration
+how long is a server side session valid in seconds (calculated after last access)
+
+defaults to session expiration
=head2 cleanup_interval
-default session expiration
+a recurring time interval when old session data gets cleaned up
+
+defaults to expiration
=head1 HELPERS
@@ -144,4 +203,4 @@ Stores and retrieves values.
$c->s3d('data');
$c->s3d->{data};
-=cut \ No newline at end of file
+=cut