added monotonic clock support to make Mojolicious more resilient to t…

…ime jumps (closes #469)
mojolicious · Mar 29, 2013 · bdc2ebd · bdc2ebd
1 parent 57dec85
commit bdc2ebd
Show file tree

Hide file tree

Showing 8 changed files with 61 additions and 29 deletions.
diff --git a/Changes b/Changes
@@ -1,5 +1,8 @@
 
-3.92  2013-03-28
+3.92  2013-03-29
+  - Added monotonic clock support to make Mojolicious more resilient to time
+    jumps.
+  - Added steady_time function to Mojo::Util.
   - Removed deprecated namespace method from Mojolicious::Routes.
   - Improved WebSocket send method to stringify objects. (jberger)
   - Improved documentation.

diff --git a/lib/Mojo/IOLoop.pm b/lib/Mojo/IOLoop.pm
@@ -9,9 +9,8 @@ use Mojo::IOLoop::Delay;
 use Mojo::IOLoop::Server;
 use Mojo::IOLoop::Stream;
 use Mojo::Reactor::Poll;
-use Mojo::Util 'md5_sum';
+use Mojo::Util qw(md5_sum steady_time);
 use Scalar::Util 'weaken';
-use Time::HiRes 'time';
 
 use constant DEBUG => $ENV{MOJO_IOLOOP_DEBUG} || 0;
 
@@ -201,7 +200,7 @@ sub _accepting {
 sub _id {
   my $self = shift;
   my $id;
-  do { $id = md5_sum('c' . time . rand 999) }
+  do { $id = md5_sum('c' . steady_time . rand 999) }
     while $self->{connections}{$id} || $self->{acceptors}{$id};
   return $id;
 }

diff --git a/lib/Mojo/IOLoop/Stream.pm b/lib/Mojo/IOLoop/Stream.pm
@@ -3,7 +3,7 @@ use Mojo::Base 'Mojo::EventEmitter';
 
 use Errno qw(EAGAIN ECONNRESET EINTR EPIPE EWOULDBLOCK);
 use Scalar::Util 'weaken';
-use Time::HiRes 'time';
+use Mojo::Util 'steady_time';
 
 has reactor => sub {
   require Mojo::IOLoop;
@@ -13,7 +13,9 @@ has timeout => 15;
 
 sub DESTROY { shift->close }
 
-sub new { shift->SUPER::new(handle => shift, buffer => '', active => time) }
+sub new {
+  shift->SUPER::new(handle => shift, buffer => '', active => steady_time);
+}
 
 sub close {
   my $self = shift;
@@ -32,7 +34,7 @@ sub handle { shift->{handle} }
 
 sub is_readable {
   my $self = shift;
-  $self->{active} = time;
+  $self->{active} = steady_time;
   return $self->{handle} && $self->reactor->is_readable($self->{handle});
 }
 
@@ -92,7 +94,7 @@ sub _read {
   # EOF
   return $self->close if $read == 0;
 
-  $self->emit_safe(read => $buffer)->{active} = time;
+  $self->emit_safe(read => $buffer)->{active} = steady_time;
 }
 
 sub _startup {
@@ -104,7 +106,8 @@ sub _startup {
   $self->{timer} = $reactor->recurring(
     0.5 => sub {
       return unless my $t = $self->timeout;
-      $self->emit_safe('timeout')->close if (time - $self->{active}) >= $t;
+      $self->emit_safe('timeout')->close
+        if (steady_time - $self->{active}) >= $t;
     }
   );
 
@@ -130,7 +133,7 @@ sub _write {
     }
 
     $self->emit_safe(write => substr($self->{buffer}, 0, $written, ''));
-    $self->{active} = time;
+    $self->{active} = steady_time;
   }
 
   $self->emit_safe('drain') if !length $self->{buffer};

diff --git a/lib/Mojo/Reactor/Poll.pm b/lib/Mojo/Reactor/Poll.pm
@@ -3,8 +3,8 @@ use Mojo::Base 'Mojo::Reactor';
 
 use IO::Poll qw(POLLERR POLLHUP POLLIN POLLOUT);
 use List::Util 'min';
-use Mojo::Util 'md5_sum';
-use Time::HiRes qw(time usleep);
+use Mojo::Util qw(md5_sum steady_time);
+use Time::HiRes 'usleep';
 
 sub io {
   my ($self, $handle, $cb) = @_;
@@ -31,7 +31,7 @@ sub one_tick {
 
     # Calculate ideal timeout based on timers
     my $min = min map { $_->{time} } values %{$self->{timers}};
-    my $timeout = defined $min ? ($min - time) : 0.5;
+    my $timeout = defined $min ? ($min - steady_time) : 0.5;
     $timeout = 0 if $timeout < 0;
 
     # I/O
@@ -48,7 +48,7 @@ sub one_tick {
 
     # Timers
     while (my ($id, $t) = each %{$self->{timers} || {}}) {
-      next unless $t->{time} <= (my $time = time);
+      next unless $t->{time} <= (my $time = steady_time);
 
       # Recurring timer
       if (exists $t->{recurring}) { $t->{time} = $time + $t->{recurring} }
@@ -106,8 +106,9 @@ sub _timer {
   my ($self, $recurring, $after, $cb) = @_;
 
   my $id;
-  do { $id = md5_sum('t' . time . rand 999) } while $self->{timers}{$id};
-  my $t = $self->{timers}{$id} = {cb => $cb, time => time + $after};
+  do { $id = md5_sum('t' . steady_time . rand 999) }
+    while $self->{timers}{$id};
+  my $t = $self->{timers}{$id} = {cb => $cb, time => steady_time + $after};
   $t->{recurring} = $after if $recurring;
 
   return $id;

diff --git a/lib/Mojo/Server/Hypnotoad.pm b/lib/Mojo/Server/Hypnotoad.pm
@@ -7,6 +7,7 @@ use Cwd 'abs_path';
 use File::Basename 'dirname';
 use File::Spec::Functions 'catfile';
 use Mojo::Server::Prefork;
+use Mojo::Util 'steady_time';
 use POSIX 'setsid';
 use Scalar::Util 'weaken';
 
@@ -62,7 +63,7 @@ sub run {
   }
 
   # Start accepting connections
-  local $SIG{USR2} = sub { $self->{upgrade} ||= time };
+  local $SIG{USR2} = sub { $self->{upgrade} ||= steady_time };
   $prefork->run;
 }
 
@@ -123,7 +124,7 @@ sub _manage {
 
     # Timeout
     kill 'KILL', $self->{new}
-      if $self->{upgrade} + $self->{upgrade_timeout} <= time;
+      if $self->{upgrade} + $self->{upgrade_timeout} <= steady_time;
   }
 }
 

diff --git a/lib/Mojo/Server/Prefork.pm b/lib/Mojo/Server/Prefork.pm
@@ -5,6 +5,7 @@ use Fcntl ':flock';
 use File::Spec::Functions qw(catfile tmpdir);
 use IO::Poll 'POLLIN';
 use List::Util 'shuffle';
+use Mojo::Util 'steady_time';
 use POSIX 'WNOHANG';
 use Scalar::Util 'weaken';
 use Time::HiRes ();
@@ -70,7 +71,7 @@ sub run {
   local $SIG{TTOU} = sub {
     $self->workers($self->workers - 1) if $self->workers > 0;
     return unless $self->workers;
-    $self->{pool}{shuffle keys %{$self->{pool}}}{graceful} ||= time;
+    $self->{pool}{shuffle keys %{$self->{pool}}}{graceful} ||= steady_time;
   };
 
   # Preload application before starting workers
@@ -89,7 +90,8 @@ sub _heartbeat {
   return unless $self->{reader}->sysread(my $chunk, 4194304);
 
   # Update heartbeats
-  $self->{pool}{$1} and $self->emit(heartbeat => $1)->{pool}{$1}{time} = time
+  my $time = steady_time;
+  $self->{pool}{$1} and $self->emit(heartbeat => $1)->{pool}{$1}{time} = $time
     while $chunk =~ /(\d+)\n/g;
 }
 
@@ -113,17 +115,18 @@ sub _manage {
     # No heartbeat (graceful stop)
     my $interval = $self->heartbeat_interval;
     my $timeout  = $self->heartbeat_timeout;
-    if (!$w->{graceful} && ($w->{time} + $interval + $timeout <= time)) {
+    my $time     = steady_time;
+    if (!$w->{graceful} && ($w->{time} + $interval + $timeout <= $time)) {
       $log->info("Worker $pid has no heartbeat, restarting.");
-      $w->{graceful} = time;
+      $w->{graceful} = $time;
     }
 
     # Graceful stop with timeout
-    $w->{graceful} ||= time if $self->{graceful};
+    $w->{graceful} ||= $time if $self->{graceful};
     if ($w->{graceful}) {
       $log->debug("Trying to stop worker $pid gracefully.");
       kill 'QUIT', $pid;
-      $w->{force} = 1 if $w->{graceful} + $self->graceful_timeout <= time;
+      $w->{force} = 1 if $w->{graceful} + $self->graceful_timeout <= $time;
     }
 
     # Normal stop
@@ -161,7 +164,8 @@ sub _spawn {
 
   # Manager
   die "Can't fork: $!" unless defined(my $pid = fork);
-  return $self->emit(spawn => $pid)->{pool}{$pid} = {time => time} if $pid;
+  return $self->emit(spawn => $pid)->{pool}{$pid} = {time => steady_time}
+    if $pid;
 
   # Prepare lock file
   my $file = $self->{lock_file};

diff --git a/lib/Mojo/Util.pm b/lib/Mojo/Util.pm
@@ -8,6 +8,11 @@ use Encode 'find_encoding';
 use File::Basename 'dirname';
 use File::Spec::Functions 'catfile';
 use MIME::Base64 qw(decode_base64 encode_base64);
+use Time::HiRes ();
+
+# Check for monotonic clock support
+use constant MONOTONIC => eval
+  '!!Time::HiRes::clock_gettime(Time::HiRes::CLOCK_MONOTONIC())';
 
 # Punycode bootstring parameters
 use constant {
@@ -42,7 +47,8 @@ our @EXPORT_OK = (
   qw(decode deprecated encode get_line hmac_md5_sum hmac_sha1_sum),
   qw(html_unescape md5_bytes md5_sum monkey_patch punycode_decode),
   qw(punycode_encode quote secure_compare sha1_bytes sha1_sum slurp spurt),
-  qw(squish trim unquote url_escape url_unescape xml_escape xor_encode)
+  qw(squish steady_time trim unquote url_escape url_unescape xml_escape),
+  qw(xor_encode)
 );
 
 # DEPRECATED in Rainbow!
@@ -291,6 +297,12 @@ sub squish {
   return $string;
 }
 
+sub steady_time () {
+  MONOTONIC
+    ? Time::HiRes::clock_gettime(Time::HiRes::CLOCK_MONOTONIC())
+    : Time::HiRes::time;
+}
+
 sub trim {
   my $string = shift;
   $string =~ s/^\s+|\s+$//g;
@@ -604,6 +616,12 @@ Write all data at once to file.
 Trim whitespace characters from both ends of string and then change all
 consecutive groups of whitespace into one space each.
 
+=head2 steady_time
+
+  my $time = steady_time;
+
+High resolution time, monotonic if possible.
+
 =head2 trim
 
   my $trimmed = trim $string;

diff --git a/t/mojo/util.t b/t/mojo/util.t
@@ -11,9 +11,9 @@ use Mojo::DeprecationTest;
 use Mojo::Util
   qw(b64_decode b64_encode camelize class_to_file class_to_path decamelize),
   qw(decode encode get_line hmac_md5_sum hmac_sha1_sum html_unescape),
-  qw(md5_bytes md5_sum monkey_patch punycode_decode squish trim unquote),
-  qw(secure_compare sha1_bytes sha1_sum slurp spurt punycode_encode quote),
-  qw(url_escape url_unescape xml_escape xor_encode);
+  qw(md5_bytes md5_sum monkey_patch punycode_decode punycode_encode quote),
+  qw(secure_compare sha1_bytes sha1_sum slurp spurt squish steady_time trim),
+  qw(unquote url_escape url_unescape xml_escape xor_encode);
 
 # camelize
 is camelize('foo_bar_baz'), 'FooBarBaz', 'right camelized result';
@@ -378,6 +378,9 @@ my $file = catfile $dir, 'test.txt';
 spurt "just\nworks!", $file;
 is slurp($file), "just\nworks!", 'successful roundtrip';
 
+# steady_time
+like steady_time, qr/^\d+\.\d+$/, 'high resolution time';
+
 # monkey_patch
 {