package Object::Remote::Connection;
use Object::Remote::Logging qw (:log :dlog router);
use Object::Remote::Future;
use Object::Remote::Null;
use Object::Remote::Handle;
use Object::Remote::CodeContainer;
use Object::Remote::GlobProxy;
use Object::Remote::GlobContainer;
use Object::Remote::Tied;
use Object::Remote;
use Symbol;
use IO::Handle;
use POSIX ":sys_wait_h";
use Module::Runtime qw(use_module);
use Scalar::Util qw(weaken blessed refaddr openhandle);
use JSON::PP qw(encode_json);
use Future;
use Carp qw(croak);
use Moo;
BEGIN { router()->exclude_forwarding }
END {
our %child_pids;
log_trace { "END handler is being invoked in " . __PACKAGE__ };
foreach(keys(%child_pids)) {
log_debug { "Killing child process '$_'" };
kill('TERM', $_);
}
}
has _id => ( is => 'ro', required => 1, default => sub { our $NEXT_CONNECTION_ID++ } );
has send_to_fh => (
is => 'ro', required => 1,
trigger => sub {
my $self = $_[0];
$_[1]->autoflush(1);
Dlog_trace { my $id = $self->_id; "connection had send_to_fh set to $_" } $_[1];
},
);
has read_channel => (
is => 'ro', required => 1,
trigger => sub {
my ($self, $ch) = @_;
my $id = $self->_id;
Dlog_trace { "trigger for read_channel has been invoked for connection $id; file handle is $_" } $ch->fh;
weaken($self);
$ch->on_line_call(sub { $self->_receive(@_) });
$ch->on_close_call(sub {
log_trace { "invoking 'done' on on_close handler for connection id '$id'" };
$self->on_close->done(@_);
});
},
);
has on_close => (
is => 'rw', default => sub { $_[0]->_install_future_handlers(Future->new) },
trigger => sub {
log_trace { "Installing handlers into future via trigger" };
$_[0]->_install_future_handlers($_[1])
},
);
has child_pid => (is => 'ro');
has local_objects_by_id => (
is => 'ro', default => sub { {} },
coerce => sub { +{ %{$_[0]} } }, # shallow clone on the way in
);
has remote_objects_by_id => (
is => 'ro', default => sub { {} },
coerce => sub { +{ %{$_[0]} } }, # shallow clone on the way in
);
has outstanding_futures => (is => 'ro', default => sub { {} });
has _json => (
is => 'lazy',
handles => {
_deserialize => 'decode',
_encode => 'encode',
},
);
after BUILD => sub {
my ($self) = @_;
my $pid = $self->child_pid;
our %child_pids;
return unless defined $pid;
$child_pids{$pid} = 1;
return;
};
sub BUILD { }
sub is_valid {
my ($self) = @_;
my $valid = ! $self->on_close->is_ready;
log_trace {
my $id = $self->_id;
my $text;
if ($valid) {
$text = 'yes';
} else {
$text = 'no';
}
"Connection '$id' is valid: '$text'"
};
return $valid;
}
sub _fail_outstanding {
my ($self, $error) = @_;
my $outstanding = $self->outstanding_futures;
Dlog_debug {
sprintf "Failing %i outstanding futures with '$error'", scalar(keys(%$outstanding))
};
foreach(keys(%$outstanding)) {
log_trace { "Failing future for $_" };
my $future = $outstanding->{$_};
$future->fail("$error\n");
}
%$outstanding = ();
return;
}
sub _install_future_handlers {
my ($self, $f) = @_;
our %child_pids;
Dlog_trace { "Installing handlers into future for connection $_" } $self->_id;
weaken($self);
$f->on_done(sub {
my $pid = $self->child_pid;
Dlog_trace { "Executing on_done handler in future for connection $_" } $self->_id;
$self->_fail_outstanding("Object::Remote connection lost: " . ($f->get)[0]);
return unless defined $pid;
log_debug { "Waiting for child '$pid' to exit" };
my $ret = waitpid($pid, 0);
if ($ret != $pid) {
log_debug { "Waited for pid $pid but waitpid() returned $ret" };
return;
} elsif ($? & 127) {
log_warn { "Remote interpreter did not exit cleanly" };
} else {
log_verbose {
my $exit_value = $? >> 8;
"Remote Perl interpreter exited with value '$exit_value'"
};
}
delete $child_pids{$pid};
});
return $f;
};
sub _id_to_remote_object {
my ($self, $id) = @_;
Dlog_trace { "fetching proxy for remote object with id '$id' for connection $_" } $self->_id;
return bless({}, 'Object::Remote::Null') if $id eq 'NULL';
(
$self->remote_objects_by_id->{$id}
or Object::Remote::Handle->new(connection => $self, id => $id)
)->proxy;
}
sub _build__json {
weaken(my $self = shift);
JSON::PP->new->filter_json_single_key_object(
__remote_object__ => sub {
$self->_id_to_remote_object(@_);
}
)->filter_json_single_key_object(
__remote_code__ => sub {
my $code_container = $self->_id_to_remote_object(@_);
sub { $code_container->call(@_) };
}
)->filter_json_single_key_object(
__scalar_ref__ => sub {
my $value = shift;
return \$value;
}
)->filter_json_single_key_object(
__glob_ref__ => sub {
my $glob_container = $self->_id_to_remote_object(@_);
my $handle = Symbol::gensym;
tie *$handle, 'Object::Remote::GlobProxy', $glob_container;
return $handle;
}
)->filter_json_single_key_object(
__local_object__ => sub {
$self->local_objects_by_id->{$_[0]}
}
)->filter_json_single_key_object(
__remote_tied_hash__ => sub {
my %tied_hash;
tie %tied_hash, 'Object::Remote::Tied', $self->_id_to_remote_object(@_);
return \%tied_hash;
}
)->filter_json_single_key_object(
__remote_tied_array__ => sub {
my @tied_array;
tie @tied_array, 'Object::Remote::Tied', $self->_id_to_remote_object(@_);
return \@tied_array;
}
);
}
sub _load_if_possible {
my ($class) = @_;
use_module($class);
if ($@) {
log_debug { "Attempt at loading '$class' failed with '$@'" };
}
}
BEGIN {
unshift our @Guess, sub { blessed($_[0]) ? $_[0] : undef };
map _load_if_possible($_), qw(
Object::Remote::Connector::Local
Object::Remote::Connector::LocalSudo
Object::Remote::Connector::SSH
Object::Remote::Connector::UNIX
);
}
sub conn_from_spec {
my ($class, $spec, @args) = @_;
foreach my $poss (do { our @Guess }) {
if (my $conn = $poss->($spec, @args)) {
return $conn;
}
}
return undef;
}
sub new_from_spec {
my ($class, $spec, @args) = @_;
return $spec if blessed $spec;
my $conn = $class->conn_from_spec($spec, @args);
die "Couldn't figure out what to do with ${spec}"
unless defined $conn;
return $conn->maybe::start::connect;
}
sub remote_object {
my ($self, @args) = @_;
Object::Remote::Handle->new(
connection => $self, @args
)->proxy;
}
sub connect {
my ($self, $to) = @_;
Dlog_debug { "Creating connection to remote node '$to' for connection $_" } $self->_id;
return await_future(
$self->send_class_call(0, 'Object::Remote', connect => $to)
);
}
sub remote_sub {
my ($self, $sub) = @_;
my ($pkg, $name) = $sub =~ m/^(.*)::([^:]+)$/;
Dlog_debug { "Invoking remote sub '$sub' for connection '$_'" } $self->_id;
return await_future($self->send_class_call(0, $pkg, can => $name));
}
sub send_class_call {
my ($self, $ctx, @call) = @_;
Dlog_trace { "Sending a class call for connection $_" } $self->_id;
$self->send(call => class_call_handler => $ctx => call => @call);
}
sub register_class_call_handler {
my ($self) = @_;
$self->local_objects_by_id->{'class_call_handler'} ||= do {
my $o = $self->new_class_call_handler;
$self->_local_object_to_id($o);
$o;
};
}
sub new_class_call_handler {
Object::Remote::CodeContainer->new(
code => sub {
my ($class, $method) = (shift, shift);
use_module($class)->$method(@_);
}
);
}
sub register_remote {
my ($self, $remote) = @_;
Dlog_trace { my $i = $remote->id; "Registered a remote object with id of '$i' for connection $_" } $self->_id;
weaken($self->remote_objects_by_id->{$remote->id} = $remote);
return $remote;
}
sub send_free {
my ($self, $id) = @_;
Dlog_trace { "sending request to free object '$id' for connection $_" } $self->_id;
#TODO this shows up some times when a remote side dies in the middle of a remote
#method invocation - possibly only when the object is being constructed?
#(in cleanup) Use of uninitialized value $id in delete at ../Object-Remote/lib/Object/Remote/Connection.
delete $self->remote_objects_by_id->{$id};
$self->_send([ free => $id ]);
}
sub send {
my ($self, $type, @call) = @_;
my $future = Future->new;
my $remote = $self->remote_objects_by_id->{$call[0]};
unshift @call, $type => $self->_local_object_to_id($future);
my $outstanding = $self->outstanding_futures;
$outstanding->{$future} = $future;
$future->on_ready(sub {
undef($remote);
delete $outstanding->{$future}
});
$self->_send(\@call);
return $future;
}
sub send_discard {
my ($self, $type, @call) = @_;
unshift @call, $type => 'NULL';
$self->_send(\@call);
}
sub _send {
my ($self, $to_send) = @_;
my $fh = $self->send_to_fh;
unless ($self->is_valid) {
croak "Attempt to invoke _send on a connection that is not valid";
}
Dlog_trace { "Starting to serialize data in argument to _send for connection $_" } $self->_id;
my $serialized = $self->_serialize($to_send)."\n";
Dlog_trace { my $l = length($serialized); "serialization is completed; sending '$l' characters of serialized data to $_" } $fh;
my $ret;
eval {
#TODO this should be converted over to a non-blocking ::WriteChannel class
die "filehandle is not open" unless openhandle($fh);
log_trace { "file handle has passed openhandle() test; printing to it" };
$ret = print $fh $serialized;
die "print was not successful: $!" unless defined $ret
};
if ($@) {
Dlog_debug { "exception encountered when trying to write to file handle $_: $@" } $fh;
my $error = $@;
chomp($error);
$self->on_close->done("could not write to file handle: $error") unless $self->on_close->is_ready;
return;
}
return $ret;
}
sub _serialize {
my ($self, $data) = @_;
local our @New_Ids = (-1);
return eval {
my $flat = $self->_encode($self->_deobjectify($data));
$flat;
} || do {
my $err = $@; # won't get here if the eval doesn't die
# don't keep refs to new things
delete @{$self->local_objects_by_id}{@New_Ids};
die "Error serializing: $err";
};
}
sub _local_object_to_id {
my ($self, $object) = @_;
my $id = refaddr($object);
$self->local_objects_by_id->{$id} ||= do {
push our(@New_Ids), $id if @New_Ids;
$object;
};
return $id;
}
sub _deobjectify {
my ($self, $data) = @_;
if (blessed($data)) {
if (
$data->isa('Object::Remote::Proxy')
and $data->{remote}->connection == $self
) {
return +{ __local_object__ => $data->{remote}->id };
} else {
return +{ __remote_object__ => $self->_local_object_to_id($data) };
}
} elsif (my $ref = ref($data)) {
if ($ref eq 'HASH') {
my $tied_to = tied(%$data);
if(defined($tied_to)) {
return +{__remote_tied_hash__ => $self->_local_object_to_id($tied_to)};
} else {
return +{ map +($_ => $self->_deobjectify($data->{$_})), keys %$data };
}
} elsif ($ref eq 'ARRAY') {
my $tied_to = tied(@$data);
if (defined($tied_to)) {
return +{__remote_tied_array__ => $self->_local_object_to_id($tied_to)};
} else {
return [ map $self->_deobjectify($_), @$data ];
}
} elsif ($ref eq 'CODE') {
my $id = $self->_local_object_to_id(
Object::Remote::CodeContainer->new(code => $data)
);
return +{ __remote_code__ => $id };
} elsif ($ref eq 'SCALAR') {
return +{ __scalar_ref__ => $$data };
} elsif ($ref eq 'GLOB') {
return +{ __glob_ref__ => $self->_local_object_to_id(
Object::Remote::GlobContainer->new(handle => $data)
) };
} else {
die "Can't collapse reftype $ref";
}
}
return $data; # plain scalar
}
sub _receive {
my ($self, $flat) = @_;
Dlog_trace { my $l = length($flat); "Starting to deserialize $l characters of data for connection $_" } $self->_id;
my ($type, @rest) = eval { @{$self->_deserialize($flat)} }
or do { warn "Deserialize failed for ${flat}: $@"; return };
Dlog_trace { "deserialization complete for connection $_" } $self->_id;
eval { $self->${\"receive_${type}"}(@rest); 1 }
or do { warn "Receive failed for ${flat}: $@"; return };
return;
}
sub receive_free {
my ($self, $id) = @_;
Dlog_trace { "got a receive_free for object '$id' for connection $_" } $self->_id;
delete $self->local_objects_by_id->{$id}
or warn "Free: no such object $id";
return;
}
sub receive_call {
my ($self, $future_id, $id, @rest) = @_;
Dlog_trace { "got a receive_call for object '$id' for connection $_" } $self->_id;
my $future = $self->_id_to_remote_object($future_id);
$future->{method} = 'call_discard_free';
my $local = $self->local_objects_by_id->{$id}
or do { $future->fail("No such object $id"); return };
$self->_invoke($future, $local, @rest);
}
sub receive_call_free {
my ($self, $future, $id, @rest) = @_;
Dlog_trace { "got a receive_call_free for object '$id' for connection $_" } $self->_id;
$self->receive_call($future, $id, undef, @rest);
$self->receive_free($id);
}
sub _invoke {
my ($self, $future, $local, $ctx, $method, @args) = @_;
Dlog_trace { "got _invoke for a method named '$method' for connection $_" } $self->_id;
if ($method =~ /^start::/) {
my $f = $local->$method(@args);
$f->on_done(sub { undef($f); $future->done(@_) });
return unless $f;
$f->on_fail(sub { undef($f); $future->fail(@_) });
return;
}
my $do = sub { $local->$method(@args) };
eval {
$future->done(
defined($ctx)
? ($ctx ? $do->() : scalar($do->()))
: do { $do->(); () }
);
1;
} or do { $future->fail($@); return; };
return;
}
1;
=head1 NAME
Object::Remote::Connection - An underlying connection for L<Object::Remote>
use Object::Remote;
my $local = Object::Remote->connect('-');
my $remote = Object::Remote->connect('myserver');
my $remote_user = Object::Remote->connect('user@myserver');
my $local_sudo = Object::Remote->connect('user@');
#$remote can be any other connection object
my $hostname = Sys::Hostname->can::on($remote, 'hostname');
=head1 DESCRIPTION
This is the class that supports connections to remote objects.
=head1 SEE ALSO
=over 4
=item C<Object::Remote::Role::Connector::PerlInterpreter>
=item C<Object::Remote>
=back
=cut