healthy.diff

diff --git a/lib/Mojo/Server/Hypnotoad.pm b/lib/Mojo/Server/Hypnotoad.pm
index d8e1682..5b09716 100644
--- a/lib/Mojo/Server/Hypnotoad.pm
+++ b/lib/Mojo/Server/Hypnotoad.pm
@@ -93,6 +93,9 @@ sub _hot_deploy {
 sub _manage {
   my $self = shift;
 
+  # Make sure all workers have a heartbeat
+  return unless $self->prefork->is_healthy;
+
   # Upgraded
   my $log = $self->prefork->app->log;
   if ($ENV{HYPNOTOAD_PID} && $ENV{HYPNOTOAD_PID} ne $$) {
diff --git a/lib/Mojo/Server/Prefork.pm b/lib/Mojo/Server/Prefork.pm
index 1052111..3a24ad7 100644
--- a/lib/Mojo/Server/Prefork.pm
+++ b/lib/Mojo/Server/Prefork.pm
@@ -58,6 +58,10 @@ sub ensure_pid_file {
   print $handle $$;
 }
 
+sub is_healthy {
+  !grep { !$_->{ok} } values %{shift->{pool}};
+}
+
 sub run {
   my $self = shift;
 
@@ -78,8 +82,9 @@ sub run {
   local $SIG{INT} = local $SIG{TERM} = sub { $self->_term };
   local $SIG{CHLD} = sub {
     while ((my $pid = waitpid -1, WNOHANG) > 0) {
-      $self->app->log->debug("Worker $pid stopped.")
-        if delete $self->emit(reap => $pid)->{pool}{$pid};
+      next unless my $w = delete $self->emit(reap => $pid)->{pool}{$pid};
+      $self->app->log->debug("Worker $pid stopped.");
+      $self->workers($self->workers - 1) unless $w->{ok};
     }
   };
   local $SIG{QUIT} = sub { $self->_term(1) };
@@ -109,7 +114,7 @@ sub _heartbeat {
   my $time = steady_time;
   while ($chunk =~ /(\d+):(\d)\n/g) {
     next unless my $w = $self->{pool}{$1};
-    $self->emit(heartbeat => $1) and $w->{time} = $time;
+    $self->emit(heartbeat => $1) and @$w{qw(ok time)} = (1, $time);
     $w->{graceful} ||= $time if $2;
   }
 }
@@ -119,7 +124,8 @@ sub _manage {
 
   # Spawn more workers if necessary and check PID file
   if (!$self->{finished}) {
-    $self->_spawn while keys %{$self->{pool}} < $self->workers;
+    $self->{finished}++ if (my $workers = $self->workers) <= 0;
+    $self->_spawn while keys %{$self->{pool}} < $workers;
     $self->ensure_pid_file;
   }