Commit | Line | Data |
9e72f0cf |
1 | package Object::Remote::Connection; |
2 | |
f4a85080 |
3 | use Object::Remote::Logging qw (:log :dlog router); |
dc28afe8 |
4 | use Object::Remote::Future; |
9d804009 |
5 | use Object::Remote::Null; |
676438a1 |
6 | use Object::Remote::Handle; |
fe6c9a7f |
7 | use Object::Remote::CodeContainer; |
ed5a8a8e |
8 | use Object::Remote::GlobProxy; |
9 | use Object::Remote::GlobContainer; |
7790ca36 |
10 | use Object::Remote::Tied; |
9e72f0cf |
11 | use Object::Remote; |
ed5a8a8e |
12 | use Symbol; |
9e72f0cf |
13 | use IO::Handle; |
c824fdf3 |
14 | use POSIX ":sys_wait_h"; |
9e72f0cf |
15 | use Module::Runtime qw(use_module); |
f8080c1c |
16 | use Scalar::Util qw(weaken blessed refaddr openhandle); |
9e72f0cf |
17 | use JSON::PP qw(encode_json); |
18 | use Moo; |
5add5e29 |
19 | use Carp qw(croak); |
9e72f0cf |
20 | |
e1a0b9ca |
21 | BEGIN { router()->exclude_forwarding } |
c824fdf3 |
22 | |
23 | END { |
24 | log_debug { "Killing all child processes in the process group" }; |
25 | |
eb351344 |
26 | #FIXME update along with setpgrp() to not use a process |
27 | #group anymore |
28 | |
c824fdf3 |
29 | #send SIGINT to the process group for our children |
30 | kill(1, -2); |
31 | } |
32 | |
9031635d |
33 | has _id => ( is => 'ro', required => 1, default => sub { our $NEXT_CONNECTION_ID++ } ); |
ad4f54b2 |
34 | |
9e72f0cf |
35 | has send_to_fh => ( |
36 | is => 'ro', required => 1, |
90115979 |
37 | trigger => sub { |
8f43bcd9 |
38 | my $self = $_[0]; |
39 | $_[1]->autoflush(1); |
40 | Dlog_trace { my $id = $self->_id; "connection had send_to_fh set to $_" } $_[1]; |
90115979 |
41 | }, |
9e72f0cf |
42 | ); |
43 | |
12fb4a80 |
44 | has read_channel => ( |
9e72f0cf |
45 | is => 'ro', required => 1, |
46 | trigger => sub { |
12fb4a80 |
47 | my ($self, $ch) = @_; |
f8080c1c |
48 | my $id = $self->_id; |
998ff9a4 |
49 | Dlog_trace { "trigger for read_channel has been invoked for connection $id; file handle is $_" } $ch->fh; |
9e72f0cf |
50 | weaken($self); |
12fb4a80 |
51 | $ch->on_line_call(sub { $self->_receive(@_) }); |
f8080c1c |
52 | $ch->on_close_call(sub { |
998ff9a4 |
53 | log_trace { "invoking 'done' on on_close handler for connection id '$id'" }; |
37efeb68 |
54 | $self->on_close->done(@_); |
f8080c1c |
55 | }); |
9e72f0cf |
56 | }, |
57 | ); |
58 | |
12fb4a80 |
59 | has on_close => ( |
353556c4 |
60 | is => 'rw', default => sub { $_[0]->_install_future_handlers(CPS::Future->new) }, |
998ff9a4 |
61 | trigger => sub { |
8f43bcd9 |
62 | log_trace { "Installing handlers into future via trigger" }; |
63 | $_[0]->_install_future_handlers($_[1]) |
998ff9a4 |
64 | }, |
12fb4a80 |
65 | ); |
ad4f54b2 |
66 | |
47c83a13 |
67 | has child_pid => (is => 'ro'); |
68 | |
11dbd4a0 |
69 | has local_objects_by_id => ( |
70 | is => 'ro', default => sub { {} }, |
71 | coerce => sub { +{ %{$_[0]} } }, # shallow clone on the way in |
72 | ); |
9e72f0cf |
73 | |
11dbd4a0 |
74 | has remote_objects_by_id => ( |
75 | is => 'ro', default => sub { {} }, |
76 | coerce => sub { +{ %{$_[0]} } }, # shallow clone on the way in |
77 | ); |
9e72f0cf |
78 | |
a980b0b8 |
79 | has outstanding_futures => (is => 'ro', default => sub { {} }); |
80 | |
353556c4 |
81 | has _json => ( |
82 | is => 'lazy', |
83 | handles => { |
84 | _deserialize => 'decode', |
85 | _encode => 'encode', |
86 | }, |
87 | ); |
88 | |
89 | after BUILD => sub { |
998ff9a4 |
90 | my ($self) = @_; |
91 | my $pid = $self->child_pid; |
353556c4 |
92 | |
998ff9a4 |
93 | unless (defined $pid) { |
8f43bcd9 |
94 | log_trace { "After BUILD invoked for connection but there was no pid" }; |
95 | return; |
998ff9a4 |
96 | } |
97 | |
98 | log_trace { "Setting process group of child process '$pid'" }; |
353556c4 |
99 | |
eb351344 |
100 | #FIXME moving things into a process group has side effects for |
101 | #users of the library - move to a list |
353556c4 |
102 | setpgrp($self->child_pid, 1); |
103 | }; |
104 | |
105 | sub BUILD { } |
106 | |
d2eadebb |
107 | sub is_valid { |
108 | my ($self) = @_; |
fb258df6 |
109 | my $valid = ! $self->on_close->is_ready; |
d2eadebb |
110 | |
fb258df6 |
111 | log_trace { |
112 | my $id = $self->_id; |
113 | my $text; |
114 | if ($valid) { |
115 | $text = 'yes'; |
116 | } else { |
117 | $text = 'no'; |
118 | } |
119 | "Connection '$id' is valid: '$text'" |
120 | }; |
121 | |
122 | return $valid; |
d2eadebb |
123 | } |
124 | |
12fb4a80 |
125 | sub _fail_outstanding { |
126 | my ($self, $error) = @_; |
127 | my $outstanding = $self->outstanding_futures; |
d2eadebb |
128 | |
129 | Dlog_debug { |
130 | sprintf "Failing %i outstanding futures with '$error'", scalar(keys(%$outstanding)) |
131 | }; |
132 | |
133 | foreach(keys(%$outstanding)) { |
134 | log_trace { "Failing future for $_" }; |
135 | my $future = $outstanding->{$_}; |
867e4de5 |
136 | $future->fail("$error\n"); |
d2eadebb |
137 | } |
138 | |
12fb4a80 |
139 | %$outstanding = (); |
140 | return; |
141 | } |
142 | |
353556c4 |
143 | sub _install_future_handlers { |
144 | my ($self, $f) = @_; |
998ff9a4 |
145 | Dlog_trace { "Installing handlers into future for connection $_" } $self->_id; |
353556c4 |
146 | weaken($self); |
147 | $f->on_done(sub { |
998ff9a4 |
148 | my $pid = $self->child_pid; |
149 | Dlog_trace { "Executing on_done handler in future for connection $_" } $self->_id; |
353556c4 |
150 | $self->_fail_outstanding("Object::Remote connection lost: " . ($f->get)[0]); |
998ff9a4 |
151 | return unless defined $pid; |
152 | log_debug { "Waiting for child '$pid' to exit" }; |
153 | my $ret = waitpid($pid, 0); |
154 | if ($ret != $pid) { |
155 | log_debug { "Waited for pid $pid but waitpid() returned $ret" }; |
156 | return; |
157 | } elsif ($? & 127) { |
158 | log_warn { "Remote interpreter did not exit cleanly" }; |
159 | } else { |
160 | log_verbose { |
161 | my $exit_value = $? >> 8; |
162 | "Remote Perl interpreter exited with value '$exit_value'" |
163 | }; |
164 | } |
353556c4 |
165 | }); |
166 | return $f; |
167 | }; |
9e72f0cf |
168 | |
fe6c9a7f |
169 | sub _id_to_remote_object { |
170 | my ($self, $id) = @_; |
9031635d |
171 | Dlog_trace { "fetching proxy for remote object with id '$id' for connection $_" } $self->_id; |
fe6c9a7f |
172 | return bless({}, 'Object::Remote::Null') if $id eq 'NULL'; |
173 | ( |
174 | $self->remote_objects_by_id->{$id} |
175 | or Object::Remote::Handle->new(connection => $self, id => $id) |
176 | )->proxy; |
177 | } |
178 | |
9e72f0cf |
179 | sub _build__json { |
180 | weaken(my $self = shift); |
9e72f0cf |
181 | JSON::PP->new->filter_json_single_key_object( |
182 | __remote_object__ => sub { |
fe6c9a7f |
183 | $self->_id_to_remote_object(@_); |
184 | } |
185 | )->filter_json_single_key_object( |
186 | __remote_code__ => sub { |
187 | my $code_container = $self->_id_to_remote_object(@_); |
188 | sub { $code_container->call(@_) }; |
9e72f0cf |
189 | } |
6ed5d580 |
190 | )->filter_json_single_key_object( |
191 | __scalar_ref__ => sub { |
192 | my $value = shift; |
193 | return \$value; |
194 | } |
ed5a8a8e |
195 | )->filter_json_single_key_object( |
196 | __glob_ref__ => sub { |
197 | my $glob_container = $self->_id_to_remote_object(@_); |
198 | my $handle = Symbol::gensym; |
199 | tie *$handle, 'Object::Remote::GlobProxy', $glob_container; |
200 | return $handle; |
201 | } |
6163a5aa |
202 | )->filter_json_single_key_object( |
203 | __local_object__ => sub { |
204 | $self->local_objects_by_id->{$_[0]} |
205 | } |
7790ca36 |
206 | )->filter_json_single_key_object( |
207 | __remote_tied_hash__ => sub { |
37efeb68 |
208 | my %tied_hash; |
209 | tie %tied_hash, 'Object::Remote::Tied', $self->_id_to_remote_object(@_); |
210 | return \%tied_hash; |
7790ca36 |
211 | } |
212 | )->filter_json_single_key_object( |
213 | __remote_tied_array__ => sub { |
37efeb68 |
214 | my @tied_array; |
215 | tie @tied_array, 'Object::Remote::Tied', $self->_id_to_remote_object(@_); |
216 | return \@tied_array; |
7790ca36 |
217 | } |
218 | ); |
9e72f0cf |
219 | } |
220 | |
c824fdf3 |
221 | sub _load_if_possible { |
222 | my ($class) = @_; |
223 | |
624072a8 |
224 | use_module($class); |
c824fdf3 |
225 | |
226 | if ($@) { |
227 | log_debug { "Attempt at loading '$class' failed with '$@'" }; |
228 | } |
229 | |
230 | } |
231 | |
84b04178 |
232 | BEGIN { |
233 | unshift our @Guess, sub { blessed($_[0]) ? $_[0] : undef }; |
c824fdf3 |
234 | map _load_if_possible($_), qw( |
235 | Object::Remote::Connector::Local |
236 | Object::Remote::Connector::LocalSudo |
237 | Object::Remote::Connector::SSH |
238 | Object::Remote::Connector::UNIX |
239 | ); |
84b04178 |
240 | } |
241 | |
c824fdf3 |
242 | sub conn_from_spec { |
243 | my ($class, $spec, @args) = @_; |
84b04178 |
244 | foreach my $poss (do { our @Guess }) { |
c824fdf3 |
245 | if (my $conn = $poss->($spec, @args)) { |
246 | return $conn; |
fbd3b8ec |
247 | } |
84b04178 |
248 | } |
c824fdf3 |
249 | |
250 | return undef; |
251 | } |
252 | |
253 | sub new_from_spec { |
71087610 |
254 | my ($class, $spec, @args) = @_; |
c824fdf3 |
255 | return $spec if blessed $spec; |
71087610 |
256 | my $conn = $class->conn_from_spec($spec, @args); |
c824fdf3 |
257 | |
258 | die "Couldn't figure out what to do with ${spec}" |
259 | unless defined $conn; |
260 | |
261 | return $conn->maybe::start::connect; |
84b04178 |
262 | } |
263 | |
11dbd4a0 |
264 | sub remote_object { |
e144d525 |
265 | my ($self, @args) = @_; |
266 | Object::Remote::Handle->new( |
267 | connection => $self, @args |
268 | )->proxy; |
269 | } |
270 | |
4c17fea5 |
271 | sub connect { |
272 | my ($self, $to) = @_; |
9031635d |
273 | Dlog_debug { "Creating connection to remote node '$to' for connection $_" } $self->_id; |
deb77aaf |
274 | return await_future( |
275 | $self->send_class_call(0, 'Object::Remote', connect => $to) |
276 | ); |
4c17fea5 |
277 | } |
278 | |
11dbd4a0 |
279 | sub remote_sub { |
c6fe6fbd |
280 | my ($self, $sub) = @_; |
281 | my ($pkg, $name) = $sub =~ m/^(.*)::([^:]+)$/; |
fb258df6 |
282 | Dlog_debug { "Invoking remote sub '$sub' for connection '$_'" } $self->_id; |
deb77aaf |
283 | return await_future($self->send_class_call(0, $pkg, can => $name)); |
284 | } |
285 | |
286 | sub send_class_call { |
287 | my ($self, $ctx, @call) = @_; |
9031635d |
288 | Dlog_trace { "Sending a class call for connection $_" } $self->_id; |
deb77aaf |
289 | $self->send(call => class_call_handler => $ctx => call => @call); |
290 | } |
291 | |
292 | sub register_class_call_handler { |
293 | my ($self) = @_; |
3687a42d |
294 | $self->local_objects_by_id->{'class_call_handler'} ||= do { |
c5736e1c |
295 | my $o = $self->new_class_call_handler; |
3687a42d |
296 | $self->_local_object_to_id($o); |
297 | $o; |
298 | }; |
c6fe6fbd |
299 | } |
300 | |
c5736e1c |
301 | sub new_class_call_handler { |
302 | Object::Remote::CodeContainer->new( |
303 | code => sub { |
304 | my ($class, $method) = (shift, shift); |
305 | use_module($class)->$method(@_); |
306 | } |
307 | ); |
308 | } |
309 | |
9e72f0cf |
310 | sub register_remote { |
311 | my ($self, $remote) = @_; |
9031635d |
312 | Dlog_trace { my $i = $remote->id; "Registered a remote object with id of '$i' for connection $_" } $self->_id; |
9e72f0cf |
313 | weaken($self->remote_objects_by_id->{$remote->id} = $remote); |
314 | return $remote; |
315 | } |
316 | |
317 | sub send_free { |
318 | my ($self, $id) = @_; |
7790ca36 |
319 | Dlog_trace { "sending request to free object '$id' for connection $_" } $self->_id; |
302ecfbf |
320 | #TODO this shows up some times when a remote side dies in the middle of a remote |
321 | #method invocation - possibly only when the object is being constructed? |
322 | #(in cleanup) Use of uninitialized value $id in delete at ../Object-Remote/lib/Object/Remote/Connection. |
9e72f0cf |
323 | delete $self->remote_objects_by_id->{$id}; |
324 | $self->_send([ free => $id ]); |
325 | } |
326 | |
327 | sub send { |
328 | my ($self, $type, @call) = @_; |
329 | |
deb77aaf |
330 | my $future = CPS::Future->new; |
a2d43709 |
331 | my $remote = $self->remote_objects_by_id->{$call[0]}; |
deb77aaf |
332 | |
333 | unshift @call, $type => $self->_local_object_to_id($future); |
9e72f0cf |
334 | |
a980b0b8 |
335 | my $outstanding = $self->outstanding_futures; |
336 | $outstanding->{$future} = $future; |
a2d43709 |
337 | $future->on_ready(sub { |
338 | undef($remote); |
339 | delete $outstanding->{$future} |
340 | }); |
a980b0b8 |
341 | |
9e72f0cf |
342 | $self->_send(\@call); |
343 | |
344 | return $future; |
345 | } |
346 | |
9d804009 |
347 | sub send_discard { |
348 | my ($self, $type, @call) = @_; |
349 | |
deb77aaf |
350 | unshift @call, $type => 'NULL'; |
9d804009 |
351 | |
352 | $self->_send(\@call); |
353 | } |
354 | |
9e72f0cf |
355 | sub _send { |
356 | my ($self, $to_send) = @_; |
9d64d2d9 |
357 | my $fh = $self->send_to_fh; |
d2eadebb |
358 | |
359 | unless ($self->is_valid) { |
5add5e29 |
360 | croak "Attempt to invoke _send on a connection that is not valid"; |
d2eadebb |
361 | } |
362 | |
9031635d |
363 | Dlog_trace { "Starting to serialize data in argument to _send for connection $_" } $self->_id; |
9d64d2d9 |
364 | my $serialized = $self->_serialize($to_send)."\n"; |
6b7b2732 |
365 | Dlog_trace { my $l = length($serialized); "serialization is completed; sending '$l' characters of serialized data to $_" } $fh; |
f8080c1c |
366 | my $ret; |
367 | eval { |
353556c4 |
368 | #TODO this should be converted over to a non-blocking ::WriteChannel class |
369 | die "filehandle is not open" unless openhandle($fh); |
370 | log_trace { "file handle has passed openhandle() test; printing to it" }; |
371 | $ret = print $fh $serialized; |
372 | die "print was not successful: $!" unless defined $ret |
f8080c1c |
373 | }; |
c824fdf3 |
374 | |
f8080c1c |
375 | if ($@) { |
353556c4 |
376 | Dlog_debug { "exception encountered when trying to write to file handle $_: $@" } $fh; |
998ff9a4 |
377 | my $error = $@; |
378 | chomp($error); |
353556c4 |
379 | $self->on_close->done("could not write to file handle: $error") unless $self->on_close->is_ready; |
380 | return; |
f8080c1c |
381 | } |
382 | |
9d64d2d9 |
383 | return $ret; |
9e72f0cf |
384 | } |
385 | |
386 | sub _serialize { |
387 | my ($self, $data) = @_; |
3687a42d |
388 | local our @New_Ids = (-1); |
9d804009 |
389 | return eval { |
ad4f54b2 |
390 | my $flat = $self->_encode($self->_deobjectify($data)); |
ad4f54b2 |
391 | $flat; |
70a578ac |
392 | } || do { |
9d804009 |
393 | my $err = $@; # won't get here if the eval doesn't die |
394 | # don't keep refs to new things |
395 | delete @{$self->local_objects_by_id}{@New_Ids}; |
396 | die "Error serializing: $err"; |
397 | }; |
9e72f0cf |
398 | } |
399 | |
a76f2f60 |
400 | sub _local_object_to_id { |
401 | my ($self, $object) = @_; |
402 | my $id = refaddr($object); |
403 | $self->local_objects_by_id->{$id} ||= do { |
3687a42d |
404 | push our(@New_Ids), $id if @New_Ids; |
a76f2f60 |
405 | $object; |
406 | }; |
407 | return $id; |
408 | } |
409 | |
9e72f0cf |
410 | sub _deobjectify { |
411 | my ($self, $data) = @_; |
412 | if (blessed($data)) { |
6163a5aa |
413 | if ( |
414 | $data->isa('Object::Remote::Proxy') |
415 | and $data->{remote}->connection == $self |
416 | ) { |
417 | return +{ __local_object__ => $data->{remote}->id }; |
418 | } else { |
419 | return +{ __remote_object__ => $self->_local_object_to_id($data) }; |
420 | } |
9e72f0cf |
421 | } elsif (my $ref = ref($data)) { |
422 | if ($ref eq 'HASH') { |
7790ca36 |
423 | my $tied_to = tied(%$data); |
424 | if(defined($tied_to)) { |
425 | return +{__remote_tied_hash__ => $self->_local_object_to_id($tied_to)}; |
426 | } else { |
427 | return +{ map +($_ => $self->_deobjectify($data->{$_})), keys %$data }; |
428 | } |
9e72f0cf |
429 | } elsif ($ref eq 'ARRAY') { |
7790ca36 |
430 | my $tied_to = tied(@$data); |
431 | if (defined($tied_to)) { |
432 | return +{__remote_tied_array__ => $self->_local_object_to_id($tied_to)}; |
433 | } else { |
434 | return [ map $self->_deobjectify($_), @$data ]; |
435 | } |
fe6c9a7f |
436 | } elsif ($ref eq 'CODE') { |
437 | my $id = $self->_local_object_to_id( |
438 | Object::Remote::CodeContainer->new(code => $data) |
439 | ); |
440 | return +{ __remote_code__ => $id }; |
6ed5d580 |
441 | } elsif ($ref eq 'SCALAR') { |
442 | return +{ __scalar_ref__ => $$data }; |
ed5a8a8e |
443 | } elsif ($ref eq 'GLOB') { |
444 | return +{ __glob_ref__ => $self->_local_object_to_id( |
445 | Object::Remote::GlobContainer->new(handle => $data) |
446 | ) }; |
9e72f0cf |
447 | } else { |
448 | die "Can't collapse reftype $ref"; |
449 | } |
450 | } |
451 | return $data; # plain scalar |
452 | } |
453 | |
9e72f0cf |
454 | sub _receive { |
ad4f54b2 |
455 | my ($self, $flat) = @_; |
9031635d |
456 | Dlog_trace { my $l = length($flat); "Starting to deserialize $l characters of data for connection $_" } $self->_id; |
ad4f54b2 |
457 | my ($type, @rest) = eval { @{$self->_deserialize($flat)} } |
458 | or do { warn "Deserialize failed for ${flat}: $@"; return }; |
9031635d |
459 | Dlog_trace { "deserialization complete for connection $_" } $self->_id; |
9e72f0cf |
460 | eval { $self->${\"receive_${type}"}(@rest); 1 } |
ad4f54b2 |
461 | or do { warn "Receive failed for ${flat}: $@"; return }; |
9e72f0cf |
462 | return; |
463 | } |
464 | |
465 | sub receive_free { |
466 | my ($self, $id) = @_; |
9031635d |
467 | Dlog_trace { "got a receive_free for object '$id' for connection $_" } $self->_id; |
9d804009 |
468 | delete $self->local_objects_by_id->{$id} |
469 | or warn "Free: no such object $id"; |
9e72f0cf |
470 | return; |
471 | } |
472 | |
473 | sub receive_call { |
deb77aaf |
474 | my ($self, $future_id, $id, @rest) = @_; |
9031635d |
475 | Dlog_trace { "got a receive_call for object '$id' for connection $_" } $self->_id; |
deb77aaf |
476 | my $future = $self->_id_to_remote_object($future_id); |
8131a88a |
477 | $future->{method} = 'call_discard_free'; |
9e72f0cf |
478 | my $local = $self->local_objects_by_id->{$id} |
479 | or do { $future->fail("No such object $id"); return }; |
480 | $self->_invoke($future, $local, @rest); |
481 | } |
482 | |
8131a88a |
483 | sub receive_call_free { |
484 | my ($self, $future, $id, @rest) = @_; |
9031635d |
485 | Dlog_trace { "got a receive_call_free for object '$id' for connection $_" } $self->_id; |
84b04178 |
486 | $self->receive_call($future, $id, undef, @rest); |
8131a88a |
487 | $self->receive_free($id); |
488 | } |
489 | |
9e72f0cf |
490 | sub _invoke { |
84b04178 |
491 | my ($self, $future, $local, $ctx, $method, @args) = @_; |
9031635d |
492 | Dlog_trace { "got _invoke for a method named '$method' for connection $_" } $self->_id; |
dc28afe8 |
493 | if ($method =~ /^start::/) { |
494 | my $f = $local->$method(@args); |
495 | $f->on_done(sub { undef($f); $future->done(@_) }); |
3f1f1e66 |
496 | return unless $f; |
dc28afe8 |
497 | $f->on_fail(sub { undef($f); $future->fail(@_) }); |
498 | return; |
499 | } |
84b04178 |
500 | my $do = sub { $local->$method(@args) }; |
501 | eval { |
502 | $future->done( |
503 | defined($ctx) |
504 | ? ($ctx ? $do->() : scalar($do->())) |
505 | : do { $do->(); () } |
506 | ); |
507 | 1; |
508 | } or do { $future->fail($@); return; }; |
9e72f0cf |
509 | return; |
510 | } |
511 | |
9e72f0cf |
512 | 1; |
b9a9982d |
513 | |
514 | =head1 NAME |
515 | |
516 | Object::Remote::Connection - An underlying connection for L<Object::Remote> |
517 | |
b0ec7e3b |
518 | use Object::Remote; |
519 | |
520 | my %opts = ( |
521 | nice => '10', ulimit => '-v 400000', |
522 | watchdog_timeout => 120, stderr => \*STDERR, |
523 | ); |
524 | |
525 | my $local = Object::Remote->connect('-'); |
526 | my $remote = Object::Remote->connect('myserver', nice => 5); |
527 | my $remote_user = Object::Remote->connect('user@myserver', %opts); |
528 | my $local_sudo = Object::Remote->connect('user@'); |
529 | |
530 | #$remote can be any other connection object |
531 | my $hostname = Sys::Hostname->can::on($remote, 'hostname'); |
532 | |
533 | =head1 DESCRIPTION |
534 | |
535 | This is the class that supports connections to a Perl interpreter that is executed in a |
536 | different process. The new Perl interpreter can be either on the local or a remote machine |
537 | and is configurable via arguments passed to the constructor. |
538 | |
539 | =head1 ARGUMENTS |
540 | |
541 | =over 4 |
542 | |
543 | =item nice |
544 | |
545 | If this value is defined then it will be used as the nice value of the Perl process when it |
546 | is started. The default is the undefined value and will not nice the process. |
547 | |
548 | =item stderr |
549 | |
550 | If this value is defined then it will be used as the file handle that receives the output |
551 | of STDERR from the Perl interpreter process and I/O will be performed by the run loop in a |
552 | non-blocking way. If the value is undefined then STDERR of the remote process will be connected |
553 | directly to STDERR of the local process with out the run loop managing I/O. The default value |
554 | is undefined. |
555 | |
556 | There are a few ways to use this feature. By default the behavior is to form one unified STDERR |
557 | across all of the Perl interpreters including the local one. For small scale and quick operation |
558 | this offers a predictable and easy to use way to get at error messages generated anywhere. If |
559 | the local Perl interpreter crashes then the remote Perl interpreters still have an active STDERR |
560 | and it is possible to still receive output from them. This is generally a good thing but can |
561 | cause issues. |
562 | |
563 | When using a file handle as the output for STDERR once the local Perl interpreter is no longer |
564 | running there is no longer a valid STDERR for the remote interpreters to send data to. This means |
565 | that it is no longer possible to receive error output from the remote interpreters and that the |
566 | shell will start to kill off the child processes. Passing a reference to STDERR for the local |
567 | interpreter (as the SYNOPSIS shows) causes the run loop to manage I/O, one unified STDERR for |
568 | all Perl interpreters that ends as soon as the local interpreter process does, and the shell will |
569 | start killing children when the local interpreter exits. |
570 | |
571 | It is also possible to pass in a file handle that has been opened for writing. This would be |
572 | useful for logging the output of the remote interpreter directly into a dedicated file. |
573 | |
574 | =item ulimit |
575 | |
576 | If this string is defined then it will be passed unmodified as the arguments to ulimit when |
577 | the Perl process is started. The default value is the undefined value and will not limit the |
578 | process in any way. |
579 | |
580 | =item watchdog_timeout |
581 | |
582 | If this value is defined then it will be used as the number of seconds the watchdog will wait |
583 | for an update before it terminates the Perl interpreter process. The default value is undefined |
584 | and will not use the watchdog. See C<Object::Remote::Watchdog> for more information. |
585 | |
586 | =back |
587 | |
588 | =head1 SEE ALSO |
589 | |
590 | =over 4 |
591 | |
592 | =item C<Object::Remote> |
b9a9982d |
593 | |
b0ec7e3b |
594 | =back |
b9a9982d |
595 | |
596 | =cut |