1Retry(3)              User Contributed Perl Documentation             Retry(3)
2
3
4

NAME

6       Retry
7

SYNOPSIS

9       A one-feature module, this provides a method to wrap any function in
10       automatic retry logic, with exponential back-off delays, and a callback
11       for each time an attempt fails.
12
13       Example:
14
15         use Retry;
16         use Try::Tiny;
17         use LWP::UserAgent;
18
19         my $code_to_retry = sub {
20           my $r = LWP::UserAgent->new->get("http://example.com");
21           die $r->status_line unless $r->is_success;
22           return $r;
23         };
24
25         my $agent = Retry->new(
26           # This callback is optional:
27           failure_callback => sub { warn "Transient error: " . $_[0]; },
28         );
29
30         try {
31           $agent->retry($code_to_retry)
32         }
33         catch {
34           warn "All attempts failed: $_";
35         };
36

ATTRIBUTES

38   retry_delay
39       This is the initial delay used when the routine failed, before retrying
40       again.
41
42       Every subsequent failure doubles the amount.
43
44       It defaults to 8 seconds.
45
46   max_retry_attempts
47       The maximum number of retries we should attempt before giving up
48       completely.
49
50       It defaults to 5.
51
52   failure_callback
53       Optional. To be notified of *every* failure (even if we eventually
54       succeed on a later retry), install a subroutine callback here.
55
56       For example:
57
58         Retry->new(
59             failure_callback => sub { warn "failed $count++ times" }
60         );
61

METHODS

63   retry
64       Its purpose is to execute the passed subroutine, over and over, until
65       it succeeds, or the number of retries is exceeded. The delay between
66       retries increases exponentially. (Failure is indicated by the sub
67       dying)
68
69       If the subroutine succeeds, then its scalar return value will be
70       returned by retry.
71
72       For example, you could replace this:
73
74         my $val = unreliable_web_request();
75
76       With this:
77
78          my $val = Retry->new->retry(
79              sub { unreliable_web_request() }
80          );
81

AUTHOR

83       Toby Corkindale -- <https://github.com/TJC/>
84

LICENSE

86       This module is released under the Perl Artistic License 2.0:
87       <http://www.perlfoundation.org/artistic_license_2_0>
88
89       It is based upon source code which is Copyright 2010 Strategic Data Pty
90       Ltd, however it is used and released with permission.
91

SEE ALSO

93       Attempt
94
95       Retry differs from Attempt in having exponentially increasing delays,
96       and by having a callback inbetween attempts.
97
98       However Attempt has a simpler syntax.
99
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101
102perl v5.34.0                      2021-07-22                          Retry(3)