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 {
15             my $subprocess = shift;
16             sleep 5;
17             return '♥', 'Mojolicious';
18           },
19           sub {
20             my ($subprocess, $err, @results) = @_;
21             say "Subprocess error: $err" and return if $err;
22             say "I $results[0] $results[1]!";
23           }
24         );
25
26         # Operation that would block the event loop for 5 seconds (with promise)
27         $subprocess->run_p(sub {
28           sleep 5;
29           return '♥', 'Mojolicious';
30         })->then(sub {
31           my @results = @_;
32           say "I $results[0] $results[1]!";
33         })->catch(sub  {
34           my $err = shift;
35           say "Subprocess error: $err";
36         });
37
38         # Start event loop if necessary
39         $subprocess->ioloop->start unless $subprocess->ioloop->is_running;
40

DESCRIPTION

42       Mojo::IOLoop::Subprocess allows Mojo::IOLoop to perform computationally
43       expensive operations in subprocesses, without blocking the event loop.
44

EVENTS

46       Mojo::IOLoop::Subprocess inherits all events from Mojo::EventEmitter
47       and can emit the following new ones.
48
49   cleanup
50         $subprocess->on(cleanup => sub {
51           my $subprocess = shift;
52           ...
53         });
54
55       Emitted in the subprocess right before the process will exit.
56
57         $subprocess->on(cleanup => sub {
58           my $subprocess = shift;
59           say "Process $$ is about to exit";
60         });
61
62   progress
63         $subprocess->on(progress => sub {
64           my ($subprocess, @data) = @_;
65           ...
66         });
67
68       Emitted in the parent process when the subprocess calls the progress
69       method.
70
71   spawn
72         $subprocess->on(spawn => sub {
73           my $subprocess = shift;
74           ...
75         });
76
77       Emitted in the parent process when the subprocess has been spawned.
78
79         $subprocess->on(spawn => sub {
80           my $subprocess = shift;
81           my $pid = $subprocess->pid;
82           say "Performing work in process $pid";
83         });
84

ATTRIBUTES

86       Mojo::IOLoop::Subprocess implements the following attributes.
87
88   deserialize
89         my $cb      = $subprocess->deserialize;
90         $subprocess = $subprocess->deserialize(sub {...});
91
92       A callback used to deserialize subprocess return values, defaults to
93       using Mojo::JSON.
94
95         $subprocess->deserialize(sub {
96           my $bytes = shift;
97           return [];
98         });
99
100   ioloop
101         my $loop    = $subprocess->ioloop;
102         $subprocess = $subprocess->ioloop(Mojo::IOLoop->new);
103
104       Event loop object to control, defaults to the global Mojo::IOLoop
105       singleton. Note that this attribute is weakened.
106
107   serialize
108         my $cb      = $subprocess->serialize;
109         $subprocess = $subprocess->serialize(sub {...});
110
111       A callback used to serialize subprocess return values, defaults to
112       using Mojo::JSON.
113
114         $subprocess->serialize(sub {
115           my $array = shift;
116           return '';
117         });
118

METHODS

120       Mojo::IOLoop::Subprocess inherits all methods from Mojo::EventEmitter
121       and implements the following new ones.
122
123   exit_code
124         my $code = $subprocess->exit_code;
125
126       Returns the subprocess exit code, or "undef" if the subprocess is still
127       running.
128
129   pid
130         my $pid = $subprocess->pid;
131
132       Process id of the spawned subprocess if available.
133
134   progress
135         $subprocess->progress(@data);
136
137       Send data serialized with Mojo::JSON to the parent process at any time
138       during the subprocess's execution. Must be called by the subprocess and
139       emits the "progress" event in the parent process with the data.
140
141         # Send progress information to the parent process
142         $subprocess->run(
143           sub {
144             my $subprocess = shift;
145             $subprocess->progress('0%');
146             sleep 5;
147             $subprocess->progress('50%');
148             sleep 5;
149             return 'Hello Mojo!';
150           },
151           sub {
152             my ($subprocess, $err, @results) = @_;
153             say 'Progress is 100%';
154             say $results[0];
155           }
156         );
157         $subprocess->on(progress => sub {
158           my ($subprocess, @data) = @_;
159           say "Progress is $data[0]";
160         });
161
162   run
163         $subprocess = $subprocess->run(sub {...}, sub {...});
164
165       Execute the first callback in a child process and wait for it to return
166       one or more values, without blocking "ioloop" in the parent process.
167       Then execute the second callback in the parent process with the
168       results. The return values of the first callback and exceptions thrown
169       by it, will be serialized with Mojo::JSON, so they can be shared
170       between processes.
171
172   run_p
173         my $promise = $subprocess->run_p(sub {...});
174
175       Same as "run", but returns a Mojo::Promise object instead of accepting
176       a second callback.
177
178         $subprocess->run_p(sub {
179           sleep 5;
180           return '♥', 'Mojolicious';
181         })->then(sub {
182           my @results = @_;
183           say "I $results[0] $results[1]!";
184         })->catch(sub {
185           my $err = shift;
186           say "Subprocess error: $err";
187         })->wait;
188

NAME

SYNOPSIS

DESCRIPTION

EVENTS

ATTRIBUTES

METHODS

SEE ALSO