package Object::Remote::Role::Connector::PerlInterpreter;
-use IPC::Open2;
+use IPC::Open3;
use IO::Handle;
+use Symbol;
+use Object::Remote::Logging qw(:log :dlog router);
use Object::Remote::ModuleSender;
use Object::Remote::Handle;
use Object::Remote::Future;
-use Object::Remote::Logging qw( :log );
-use Scalar::Util qw(blessed);
+use Scalar::Util qw(blessed weaken);
use Moo::Role;
with 'Object::Remote::Role::Connector';
has module_sender => (is => 'lazy');
+has watchdog_timeout => ( is => 'ro', required => 1, default => sub { undef });
+has forward_env => (is => 'ro', required => 1, builder => 1);
+has perl_command => (is => 'lazy');
+has pid => (is => 'rwp');
+has connection_id => (is => 'rwp');
+
+#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 { undef } );
+
+BEGIN { router()->exclude_forwarding; }
sub _build_module_sender {
my ($hook) =
return $hook ? $hook->sender : Object::Remote::ModuleSender->new;
}
-has perl_command => (is => 'lazy');
+#By policy object-remote does not invoke a shell
+sub _build_perl_command {
+ my $perl_bin = 'perl';
-sub _build_perl_command { [ 'perl', '-' ] }
+ if (exists $ENV{OBJECT_REMOTE_PERL_BIN}) {
+ $perl_bin = $ENV{OBJECT_REMOTE_PERL_BIN};
+ }
+ return [$perl_bin, '-'];
+}
+
+sub _build_forward_env {
+ return [qw(
+ OBJECT_REMOTE_PERL_BIN
+ OBJECT_REMOTE_LOG_LEVEL OBJECT_REMOTE_LOG_FORMAT OBJECT_REMOTE_LOG_SELECTIONS
+ OBJECT_REMOTE_LOG_FORWARDING
+ )];
+}
around connect => sub {
my ($orig, $self) = (shift, shift);
return future {
$f->on_done(sub {
my ($conn) = $f->get;
- my $sub = $conn->remote_sub('Object::Remote::Logging::init_logging_forwarding');
- $sub->('Object::Remote::Logging', Object::Remote::Logging->arg_router);
+ $self->_setup_watchdog_reset($conn);
+ my $sub = $conn->remote_sub('Object::Remote::Logging::init_remote_logging');
+ $sub->('Object::Remote::Logging', router => router(), connection_id => $conn->_id);
Object::Remote::Handle->new(
connection => $conn,
class => 'Object::Remote::ModuleLoader',
sub _start_perl {
my $self = shift;
- my $pid = open2(
- my $foreign_stdout,
+ my $given_stderr = $self->stderr;
+ my $foreign_stderr;
+
+ Dlog_verbose {
+ s/\n/ /g; "invoking connection to perl interpreter using command line: $_"
+ } @{$self->final_perl_command};
+
+ if (defined($given_stderr)) {
+ #if the stderr data goes to an existing file handle
+ #an anonymous file handle is required
+ #as the other half of a pipe style file handle pair
+ #so the file handles can go into the run loop
+ $foreign_stderr = gensym();
+ } else {
+ #if no file handle has been specified
+ #for the child's stderr then connect
+ #the child stderr to the parent stderr
+ $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]': $!";
+
+ $self->_set_pid($pid);
+
+ if (defined($given_stderr)) {
+ Dlog_debug { "Child process STDERR is being handled via run loop" };
+
+ 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: $!";
+ }
+ }
+ );
+ }
+
return ($foreign_stdin, $foreign_stdout, $pid);
}
my $self = shift;
my ($foreign_stdin, $foreign_stdout, $pid) = $self->_start_perl(@_);
my $to_send = $self->fatnode_text;
+ log_debug { my $len = length($to_send); "Sending contents of fat node to remote node; size is '$len' characters" };
Object::Remote->current_loop
->watch_io(
handle => $foreign_stdin,
on_write_ready => sub {
- my $len = syswrite($foreign_stdin, $to_send, 4096);
+ my $len = syswrite($foreign_stdin, $to_send, 32768);
if (defined $len) {
substr($to_send, 0, $len) = '';
}
# if the stdin went away, we'll never get Shere
# so it's not a big deal to simply give up on !defined
if (!defined($len) or 0 == length($to_send)) {
+ log_trace { "Got EOF or error when writing fatnode data to filehandle, unwatching it" };
Object::Remote->current_loop
->unwatch_io(
handle => $foreign_stdin,
on_write_ready => 1
- );
+ );
+ } else {
+ log_trace { "Sent $len bytes of fatnode data to remote side" };
}
}
);
return ($foreign_stdin, $foreign_stdout, $pid);
}
+sub _setup_watchdog_reset {
+ my ($self, $conn) = @_;
+ my $timer_id;
+
+ return unless $self->watchdog_timeout;
+
+ Dlog_trace { "Creating Watchdog management timer for connection id $_" } $conn->_id;
+
+ weaken($conn);
+
+ $timer_id = Object::Remote->current_loop->watch_time(
+ every => $self->watchdog_timeout / 3,
+ code => sub {
+ unless(defined($conn)) {
+ log_warn { "Weak reference to connection in Watchdog was lost, terminating update timer $timer_id" };
+ Object::Remote->current_loop->unwatch_time($timer_id);
+ return;
+ }
+
+ unless($conn->is_valid) {
+ log_warn { "Watchdog timer found an invalid connection, removing the timer" };
+ Object::Remote->current_loop->unwatch_time($timer_id);
+ return;
+ }
+
+ Dlog_trace { "Reseting Watchdog for connection id $_" } $conn->_id;
+ #we do not want to block in the run loop so send the
+ #update off and ignore any result, we don't need it
+ #anyway
+ $conn->send_class_call(0, 'Object::Remote::WatchDog', 'reset');
+ }
+ );
+
+ $conn->on_close->on_ready(sub {
+ log_debug { "Removing watchdog for connection that is now closed" };
+ Object::Remote->current_loop->unwatch_time($timer_id);
+ });
+}
+
sub fatnode_text {
my ($self) = @_;
- require Object::Remote::FatNode;
+ my $connection_timeout = $self->timeout;
+ my $watchdog_timeout = $self->watchdog_timeout;
my $text = '';
- $text .= 'BEGIN { $ENV{OBJECT_REMOTE_DEBUG} = 1 }'."\n"
- if $ENV{OBJECT_REMOTE_DEBUG};
+
+ require Object::Remote::FatNode;
+
+ if (defined($connection_timeout)) {
+ $text .= "alarm($connection_timeout);\n";
+ }
+
+ if (defined($watchdog_timeout)) {
+ $text .= "my \$WATCHDOG_TIMEOUT = $watchdog_timeout;\n";
+ } else {
+ $text .= "my \$WATCHDOG_TIMEOUT = undef;\n";
+ }
+
+ $text .= $self->_create_env_forward(@{$self->forward_env});
+
+ #Action at a distance but at least it's not spooky - the logging
+ #system needs to know if a node is remote but there is a period
+ #during init where the remote connection information has not been
+ #setup on the remote side yet so this flag allows a graceful
+ #degredation to happen
+ $text .= '$Object::Remote::FatNode::REMOTE_NODE = "1";' . "\n";
+
$text .= <<'END';
$INC{'Object/Remote/FatNode.pm'} = __FILE__;
$Object::Remote::FatNode::DATA = <<'ENDFAT';
eval $Object::Remote::FatNode::DATA;
die $@ if $@;
END
+
$text .= "__END__\n";
return $text;
}
+sub _create_env_forward {
+ my ($self, @env_names) = @_;
+ my $code = '';
+
+ foreach my $name (@env_names) {
+ next unless exists $ENV{$name};
+ my $value = $ENV{$name};
+ $name =~ s/'/\\'/g;
+ if(defined($value)) {
+ $value =~ s/'/\\'/g;
+ $value = "'$value'";
+ } else {
+ $value = 'undef';
+ }
+ $code .= "\$ENV{'$name'} = $value;\n";
+ }
+
+ return $code;
+}
+
1;
+
+=head1 NAME
+
+Object::Remote::Role::Connector::PerlInterpreter - Role for connections to a Perl interpreter
+
+=head1 SYNOPSIS
+
+ use Object::Remote;
+
+ my %opts = (
+ perl_command => [qw(nice -n 10 perl -)],
+ watchdog_timeout => 120, stderr => \*STDERR,
+ );
+
+ my $local_connection = Object::Remote->connect('-', %opts);
+ my $hostname = Sys::Hostname->can::on($remote, 'hostname');
+
+=head1 DESCRIPTION
+
+This is the role that supports connections to a Perl interpreter that is executed in a
+different process. The new Perl interpreter can be either on the local or a remote machine
+and is configurable via arguments passed to the constructor.
+
+=head1 ARGUMENTS
+
+=over 4
+
+=item perl_command
+
+By default the Perl interpeter will be executed as "perl -" but this can be changed by
+providing an array reference as the value to the perl_command attribute during construction.
+
+=item stderr
+
+If this value is defined then it will be used as the file handle that receives the output
+of STDERR from the Perl interpreter process and I/O will be performed by the run loop in a
+non-blocking way. If the value is undefined then STDERR of the remote process will be connected
+directly to STDERR of the local process with out the run loop managing I/O. The default value
+is undefined.
+
+There are a few ways to use this feature. By default the behavior is to form one unified STDERR
+across all of the Perl interpreters including the local one. For small scale and quick operation
+this offers a predictable and easy to use way to get at error messages generated anywhere. If
+the local Perl interpreter crashes then the remote Perl interpreters still have an active STDERR
+and it is possible to still receive output from them. This is generally a good thing but can
+cause issues.
+
+When using a file handle as the output for STDERR once the local Perl interpreter is no longer
+running there is no longer a valid STDERR for the remote interpreters to send data to. This means
+that it is no longer possible to receive error output from the remote interpreters and that the
+shell will start to kill off the child processes. Passing a reference to STDERR for the local
+interpreter (as the SYNOPSIS shows) causes the run loop to manage I/O, one unified STDERR for
+all Perl interpreters that ends as soon as the local interpreter process does, and the shell will
+start killing children when the local interpreter exits.
+
+It is also possible to pass in a file handle that has been opened for writing. This would be
+useful for logging the output of the remote interpreter directly into a dedicated file.
+
+=item watchdog_timeout
+
+If this value is defined then it will be used as the number of seconds the watchdog will wait
+for an update before it terminates the Perl interpreter process. The default value is undefined
+and will not use the watchdog. See C<Object::Remote::Watchdog> for more information.
+
+=back
+
+=head1 SEE ALSO
+
+=over 4
+
+=item C<Object::Remote>
+
+=back
+
+=cut