From: Tyler Riddle <t.riddle@shadowcat.co.uk>
Date: Fri, 21 Sep 2012 20:20:27 +0000 (-0700)
Subject: add non-blocking file handle support for reading in miniloop and change miniloop... 
X-Git-Tag: v0.003001_01~111
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?p=scpubgit%2FObject-Remote.git;a=commitdiff_plain;h=6b7b2732b7cc6b6c626469f2e6300b7012caef07

add non-blocking file handle support for reading in miniloop and change miniloop to be safer under recursion; performing manual management of child process stderr
---

diff --git a/lib/Object/Remote/Connection.pm b/lib/Object/Remote/Connection.pm
index ef44655..d338a21 100644
--- a/lib/Object/Remote/Connection.pm
+++ b/lib/Object/Remote/Connection.pm
@@ -239,7 +239,7 @@ sub _send {
   my $fh = $self->send_to_fh;
   Dlog_trace { "Starting to serialize data in argument to _send for connection $_" } $self->_id;
   my $serialized = $self->_serialize($to_send)."\n";
-  Dlog_debug { my $l = length($serialized); "serialization is completed; sending '$l' characters of serialized data to $_" } $fh;
+  Dlog_trace { my $l = length($serialized); "serialization is completed; sending '$l' characters of serialized data to $_" } $fh;
   #TODO this is very risky for deadlocks unless it's set to non-blocking and then with out extra
   #logic it could easily do short-writes to the remote side
   my $ret = print $fh $serialized;
@@ -252,7 +252,6 @@ sub _send {
 sub _serialize {
   my ($self, $data) = @_;
   local our @New_Ids = (-1);
-  Dlog_debug { "starting to serialize data for connection $_" } $self->_id;
   return eval {
     my $flat = $self->_encode($self->_deobjectify($data));
     warn "$$ >>> ${flat}\n" if $DEBUG;
diff --git a/lib/Object/Remote/Future.pm b/lib/Object/Remote/Future.pm
index 2817539..d6d6081 100644
--- a/lib/Object/Remote/Future.pm
+++ b/lib/Object/Remote/Future.pm
@@ -29,15 +29,15 @@ sub await_future {
     $f->on_ready(sub {
       log_trace { my $l = @await; "future has become ready, length of \@await: '$l'" };
       if ($f == $await[-1]) {
-        log_debug { "This future is not waiting on anything so calling stop on the run loop" };
+        log_trace { "This future is not waiting on anything so calling stop on the run loop" };
         $loop->stop;         
       }
     });
-    log_debug { "Starting run loop for newly created future" };
+    log_trace { "Starting run loop for newly created future" };
     $loop->run;
   }
   if (@await and $await[-1]->is_ready) {
-    log_debug { "Last future in await list was ready, stopping run loop" };
+    log_trace { "Last future in await list was ready, stopping run loop" };
     $loop->stop;
   }
   log_trace { "await_future() returning" };
diff --git a/lib/Object/Remote/MiniLoop.pm b/lib/Object/Remote/MiniLoop.pm
index 5f22eac..18c0b47 100644
--- a/lib/Object/Remote/MiniLoop.pm
+++ b/lib/Object/Remote/MiniLoop.pm
@@ -43,13 +43,15 @@ sub watch_io {
   #will need to be integrated in a way that
   #is compatible with Windows which has no
   #non-blocking support
-  Dlog_warn { "setting file handle to be non-blocking: " } $fh;
-  use Fcntl qw(F_GETFL F_SETFL O_NONBLOCK);
-  my $flags = fcntl($fh, F_GETFL, 0)
-    or die "Can't get flags for the socket: $!\n";
-  $flags = fcntl($fh, F_SETFL, $flags | O_NONBLOCK)
-    or die "Can't set flags for the socket: $!\n";
-
+  if (0) {
+    Dlog_warn { "setting file handle to be non-blocking: $_" } $fh;
+    use Fcntl qw(F_GETFL F_SETFL O_NONBLOCK);
+    my $flags = fcntl($fh, F_GETFL, 0)
+      or die "Can't get flags for the socket: $!\n";
+    $flags = fcntl($fh, F_SETFL, $flags | O_NONBLOCK)
+      or die "Can't set flags for the socket: $!\n"; 
+  }
+  
   if (my $cb = $watch{on_read_ready}) {
     log_trace { "IO watcher is registering with select for reading" };
     $self->_read_select->add($fh);
@@ -122,8 +124,6 @@ sub _next_timer_expires_delay {
     $duration = $delay_max;
   }
   
-  #uncomment for original behavior
-  #return .5;    
   return $duration; 
 }
 
@@ -131,11 +131,12 @@ sub loop_once {
   my ($self) = @_;
   my $read = $self->_read_watches;
   my $write = $self->_write_watches;
+  our $Loop_Entered = 1; 
   my $read_count = 0;
   my $write_count = 0; 
   my @c = caller;
   my $wait_time = $self->_next_timer_expires_delay;
-  log_debug {  sprintf("Run loop: loop_once() has been invoked by $c[1]:$c[2] with read:%i write:%i select timeout:%s",
+  log_trace {  sprintf("Run loop: loop_once() has been invoked by $c[1]:$c[2] with read:%i write:%i select timeout:%s",
       scalar(keys(%$read)), scalar(keys(%$write)), defined $wait_time ? $wait_time : 'indefinite' ) };
   #TODO The docs state that select() in some instances can return a socket as ready to
   #read data even if reading from it would block and the recomendation is to set
@@ -155,7 +156,7 @@ sub loop_once {
     #return? 
     $self->_read_select, $self->_write_select, undef, $wait_time
   ); 
-  log_debug { 
+  log_trace { 
     my $readable_count = defined $readable ? scalar(@$readable) : 0;
     my $writable_count = defined $writeable ? scalar(@$writeable) : 0;
     "Run loop: select returned readable:$readable_count writeable:$writable_count";
@@ -163,11 +164,15 @@ sub loop_once {
   # I would love to trap errors in the select call but IO::Select doesn't
   # differentiate between an error and a timeout.
   #   -- no, love, mst.
+
+  local $Loop_Entered;
+
   log_trace { "Reading from all ready filehandles" };
   foreach my $fh (@$readable) {
     next unless $read->{$fh};
     $read_count++;
     $read->{$fh}();
+    last if $Loop_Entered;
 #    $read->{$fh}() if $read->{$fh};
   }
   log_trace { "Writing to all ready filehandles" };
@@ -175,6 +180,7 @@ sub loop_once {
     next unless $write->{$fh};
     $write_count++;
     $write->{$fh}();
+    last if $Loop_Entered;
 #    $write->{$fh}() if $write->{$fh};
   }
   log_trace { "Read from $read_count filehandles; wrote to $write_count filehandles" };
@@ -184,8 +190,9 @@ sub loop_once {
   while (@$timers and $timers->[0][0] <= $now) {
     Dlog_debug { "Found timer that needs to be executed: $_" } $timers->[0];
     (shift @$timers)->[1]->();
+    last if $Loop_Entered;
   }
-  log_debug { "Run loop: single loop is completed" };
+  log_trace { "Run loop: single loop is completed" };
   return;
 }
 
@@ -223,12 +230,12 @@ sub want_stop {
 #will with out interfering with each other 
 sub run {
   my ($self) = @_;
-  log_info { "Run loop: run() invoked" };
+  log_trace { "Run loop: run() invoked" };
   local $self->{is_running} = 1;
   while ($self->is_running) {
     $self->loop_once;
   }
-  log_info { "Run loop: run() completed" };
+  log_trace { "Run loop: run() completed" };
   return;
 }
 
diff --git a/lib/Object/Remote/Role/Connector/PerlInterpreter.pm b/lib/Object/Remote/Role/Connector/PerlInterpreter.pm
index b1efd9b..291a664 100644
--- a/lib/Object/Remote/Role/Connector/PerlInterpreter.pm
+++ b/lib/Object/Remote/Role/Connector/PerlInterpreter.pm
@@ -1,6 +1,6 @@
 package Object::Remote::Role::Connector::PerlInterpreter;
 
-#use IPC::Open2;
+use IPC::Open2;
 use IPC::Open3; 
 use IO::Handle;
 use Object::Remote::ModuleSender;
@@ -13,6 +13,9 @@ use Moo::Role;
 with 'Object::Remote::Role::Connector';
 
 has module_sender => (is => 'lazy');
+#if no child_stderr file handle is specified then stderr
+#of the child will be connected to stderr of the parent
+has stderr => ( is => 'rw', default => sub { \*STDERR } );
 
 sub _build_module_sender {
   my ($hook) =
@@ -28,6 +31,7 @@ has perl_command => (is => 'lazy');
 #ulimit of ~500 megs of v-ram
 #TODO only works with ssh with quotes but only works locally
 #with out quotes
+#sub _build_perl_command { [ 'sh', '-c', '"ulimit -v 80000; nice -n 15 perl -"' ] }
 sub _build_perl_command { [ 'sh', '-c', '"ulimit -v 500000; nice -n 15 perl -"' ] }
 #sub _build_perl_command { [ 'perl', '-' ] }
 
@@ -55,8 +59,52 @@ sub final_perl_command { shift->perl_command }
 
 sub _start_perl {
   my $self = shift;
+  my $given_stderr = $self->stderr;
+  my $foreign_stderr;
+ 
   Dlog_debug { "invoking connection to perl interpreter using command line: $_" } @{$self->final_perl_command};
   
+  use Symbol; 
+  
+  if (defined($given_stderr)) {
+      $foreign_stderr = gensym();
+  } else {
+      $foreign_stderr = ">&STDERR";
+  }
+  
+  my $pid = open3(
+    my $foreign_stdin,
+    my $foreign_stdout,
+    $foreign_stderr,
+    @{$self->final_perl_command},
+  ) or die "Failed to run perl at '$_[0]': $!";
+  
+  if (defined($given_stderr)) {   
+      log_warn { "using experimental cat for child stderr" };
+        
+      #TODO refactor if this solves the problem
+      Object::Remote->current_loop
+                    ->watch_io(
+                        handle => $foreign_stderr,
+                        on_read_ready => sub {
+                          my $buf = ''; 
+                          my $len = sysread($foreign_stderr, $buf, 32768);
+                          if (!defined($len) or $len == 0) {
+                            log_trace { "Got EOF or error on child stderr, removing from watcher" };
+                            $self->stderr(undef);
+                            Object::Remote->current_loop
+                                          ->unwatch_io(
+                                              handle => $foreign_stderr,
+                                              on_read_ready => 1
+                                            );
+                          } else {
+                              Dlog_trace { "got $len characters of stderr data for connection" };
+                              print $given_stderr $buf or die "could not send stderr data: $!";
+                          }
+                         }
+                      );     
+  }
+      
   #TODO open2() dupes the child stderr into the calling
   #process stderr which means if this process exits the
   #child is still attached to the shell - using open3()
@@ -69,11 +117,11 @@ sub _start_perl {
   #where the user of a connection species a destination for output
   #either a file name or their own file handle and the node output
   #is dumped to it 
-  my $pid = open2(
-    my $foreign_stdout,
-    my $foreign_stdin,
-    @{$self->final_perl_command},
-  ) or die "Failed to run perl at '$_[0]': $!";
+#  my $pid = open2(
+#    my $foreign_stdout,
+#    my $foreign_stdin,
+#    @{$self->final_perl_command},
+#  ) or die "Failed to run perl at '$_[0]': $!";
 
   Dlog_trace { "Connection to remote side successful; remote stdin and stdout: $_" } [ $foreign_stdin, $foreign_stdout ];
   return ($foreign_stdin, $foreign_stdout, $pid);