Mojo::IOLoop::Subprocess(3pm)

1Mojo::IOLoop::SubprocesUss(e3r)Contributed Perl DocumentMaotjioo:n:IOLoop::Subprocess(3)
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NAME

6       Mojo::IOLoop::Subprocess - Subprocesses
7

SYNOPSIS

9         use Mojo::IOLoop::Subprocess;
10
11         # Operation that would block the event loop for 5 seconds
12         my $subprocess = Mojo::IOLoop::Subprocess->new;
13         $subprocess->run(
14           sub ($subprocess) {
15             sleep 5;
16             return '♥', 'Mojolicious';
17           },
18           sub ($subprocess, $err, @results) {
19             say "Subprocess error: $err" and return if $err;
20             say "I $results[0] $results[1]!";
21           }
22         );
23
24         # Operation that would block the event loop for 5 seconds (with promise)
25         $subprocess->run_p(sub {
26           sleep 5;
27           return '♥', 'Mojolicious';
28         })->then(sub (@results) {
29           say "I $results[0] $results[1]!";
30         })->catch(sub  {
31           my $err = shift;
32           say "Subprocess error: $err";
33         });
34
35         # Start event loop if necessary
36         $subprocess->ioloop->start unless $subprocess->ioloop->is_running;
37

DESCRIPTION

39       Mojo::IOLoop::Subprocess allows Mojo::IOLoop to perform computationally
40       expensive operations in subprocesses, without blocking the event loop.
41

EVENTS

43       Mojo::IOLoop::Subprocess inherits all events from Mojo::EventEmitter
44       and can emit the following new ones.
45
46   cleanup
47         $subprocess->on(cleanup => sub ($subprocess) {...});
48
49       Emitted in the subprocess right before the process will exit.
50
51         $subprocess->on(cleanup => sub ($subprocess) { say "Process $$ is about to exit" });
52
53   progress
54         $subprocess->on(progress => sub ($subprocess, @data) {...});
55
56       Emitted in the parent process when the subprocess calls the progress
57       method.
58
59   spawn
60         $subprocess->on(spawn => sub ($subprocess) {...});
61
62       Emitted in the parent process when the subprocess has been spawned.
63
64         $subprocess->on(spawn => sub ($subprocess) {
65           my $pid = $subprocess->pid;
66           say "Performing work in process $pid";
67         });
68

ATTRIBUTES

70       Mojo::IOLoop::Subprocess implements the following attributes.
71
72   deserialize
73         my $cb      = $subprocess->deserialize;
74         $subprocess = $subprocess->deserialize(sub {...});
75
76       A callback used to deserialize subprocess return values, defaults to
77       using Mojo::JSON.
78
79         $subprocess->deserialize(sub ($bytes) { return [] });
80
81   ioloop
82         my $loop    = $subprocess->ioloop;
83         $subprocess = $subprocess->ioloop(Mojo::IOLoop->new);
84
85       Event loop object to control, defaults to the global Mojo::IOLoop
86       singleton. Note that this attribute is weakened.
87
88   serialize
89         my $cb      = $subprocess->serialize;
90         $subprocess = $subprocess->serialize(sub {...});
91
92       A callback used to serialize subprocess return values, defaults to
93       using Mojo::JSON.
94
95         $subprocess->serialize(sub ($array) { return '' });
96

METHODS

98       Mojo::IOLoop::Subprocess inherits all methods from Mojo::EventEmitter
99       and implements the following new ones.
100
101   exit_code
102         my $code = $subprocess->exit_code;
103
104       Returns the subprocess exit code, or "undef" if the subprocess is still
105       running.
106
107   pid
108         my $pid = $subprocess->pid;
109
110       Process id of the spawned subprocess if available.
111
112   progress
113         $subprocess->progress(@data);
114
115       Send data serialized with Mojo::JSON to the parent process at any time
116       during the subprocess's execution. Must be called by the subprocess and
117       emits the "progress" event in the parent process with the data.
118
119         # Send progress information to the parent process
120         $subprocess->run(
121           sub ($subprocess) {
122             $subprocess->progress('0%');
123             sleep 5;
124             $subprocess->progress('50%');
125             sleep 5;
126             return 'Hello Mojo!';
127           },
128           sub ($subprocess, $err, @results) {
129             say 'Progress is 100%';
130             say $results[0];
131           }
132         );
133         $subprocess->on(progress => sub ($subprocess, @data) { say "Progress is $data[0]" });
134
135   run
136         $subprocess = $subprocess->run(sub {...}, sub {...});
137
138       Execute the first callback in a child process and wait for it to return
139       one or more values, without blocking "ioloop" in the parent process.
140       Then execute the second callback in the parent process with the
141       results. The return values of the first callback and exceptions thrown
142       by it, will be serialized with Mojo::JSON, so they can be shared
143       between processes.
144
145   run_p
146         my $promise = $subprocess->run_p(sub {...});
147
148       Same as "run", but returns a Mojo::Promise object instead of accepting
149       a second callback.
150
151         $subprocess->run_p(sub {
152           sleep 5;
153           return '♥', 'Mojolicious';
154         })->then(sub (@results) {
155           say "I $results[0] $results[1]!";
156         })->catch(sub ($err) {
157           say "Subprocess error: $err";
158         })->wait;
159

NAME

SYNOPSIS

DESCRIPTION

EVENTS

ATTRIBUTES

METHODS

SEE ALSO