Commit | Line | Data |
9345b14c |
1 | package # hide from pause until we figure it all out |
2 | DBIx::Class::Storage::BlockRunner; |
3 | |
7f9a3f70 |
4 | use warnings; |
59d624cf |
5 | use strict; |
6 | |
cbd7f87a |
7 | use DBIx::Class::Carp; |
8 | use Context::Preserve 'preserve_context'; |
ddcc02d1 |
9 | use DBIx::Class::_Util qw( is_exception qsub dbic_internal_try ); |
cbd7f87a |
10 | use Scalar::Util qw(weaken blessed reftype); |
11 | use Try::Tiny; |
0020e364 |
12 | use Moo; |
9345b14c |
13 | use namespace::clean; |
14 | |
15 | =head1 NAME |
16 | |
17 | DBIx::Class::Storage::BlockRunner - Try running a block of code until success with a configurable retry logic |
18 | |
19 | =head1 DESCRIPTION |
20 | |
21 | =head1 METHODS |
22 | |
23 | =cut |
24 | |
25 | has storage => ( |
26 | is => 'ro', |
27 | required => 1, |
28 | ); |
29 | |
30 | has wrap_txn => ( |
31 | is => 'ro', |
32 | required => 1, |
33 | ); |
34 | |
35 | # true - retry, false - rethrow, or you can throw your own (not catching) |
36 | has retry_handler => ( |
37 | is => 'ro', |
38 | required => 1, |
7f9a3f70 |
39 | isa => qsub q{ |
7d534e68 |
40 | (Scalar::Util::reftype($_[0])||'') eq 'CODE' |
9345b14c |
41 | or DBIx::Class::Exception->throw('retry_handler must be a CODE reference') |
7f9a3f70 |
42 | }, |
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43 | ); |
44 | |
45 | has retry_debug => ( |
46 | is => 'rw', |
7d534e68 |
47 | # use a sub - to be evaluated on the spot lazily |
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48 | default => qsub '$ENV{DBIC_STORAGE_RETRY_DEBUG}', |
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49 | lazy => 1, |
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50 | ); |
51 | |
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52 | has max_attempts => ( |
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53 | is => 'ro', |
7d534e68 |
54 | default => 20, |
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55 | ); |
56 | |
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57 | has failed_attempt_count => ( |
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58 | is => 'ro', |
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59 | init_arg => undef, # ensures one can't pass the value in |
60 | writer => '_set_failed_attempt_count', |
61 | default => 0, |
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62 | lazy => 1, |
7f9a3f70 |
63 | trigger => qsub q{ |
f9080e45 |
64 | $_[0]->throw_exception( sprintf ( |
7d534e68 |
65 | 'Reached max_attempts amount of %d, latest exception: %s', |
66 | $_[0]->max_attempts, $_[0]->last_exception |
67 | )) if $_[0]->max_attempts <= ($_[1]||0); |
7f9a3f70 |
68 | }, |
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69 | ); |
70 | |
71 | has exception_stack => ( |
72 | is => 'ro', |
73 | init_arg => undef, |
74 | clearer => '_reset_exception_stack', |
7f9a3f70 |
75 | default => qsub q{ [] }, |
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76 | lazy => 1, |
77 | ); |
78 | |
79 | sub last_exception { shift->exception_stack->[-1] } |
80 | |
f9080e45 |
81 | sub throw_exception { shift->storage->throw_exception (@_) } |
82 | |
9345b14c |
83 | sub run { |
84 | my $self = shift; |
85 | |
9345b14c |
86 | $self->_reset_exception_stack; |
7d534e68 |
87 | $self->_set_failed_attempt_count(0); |
88 | |
89 | my $cref = shift; |
90 | |
91 | $self->throw_exception('run() requires a coderef to execute as its first argument') |
92 | if ( reftype($cref)||'' ) ne 'CODE'; |
93 | |
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94 | my $storage = $self->storage; |
95 | |
7d534e68 |
96 | return $cref->( @_ ) if ( |
97 | $storage->{_in_do_block} |
98 | and |
99 | ! $self->wrap_txn |
100 | ); |
9345b14c |
101 | |
102 | local $storage->{_in_do_block} = 1 unless $storage->{_in_do_block}; |
103 | |
7d534e68 |
104 | return $self->_run($cref, @_); |
9345b14c |
105 | } |
106 | |
107 | # this is the actual recursing worker |
108 | sub _run { |
7d534e68 |
109 | # internal method - we know that both refs are strong-held by the |
110 | # calling scope of run(), hence safe to weaken everything |
111 | weaken( my $self = shift ); |
112 | weaken( my $cref = shift ); |
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113 | |
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114 | my $args = @_ ? \@_ : []; |
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115 | |
116 | # from this point on (defined $txn_init_depth) is an indicator for wrap_txn |
117 | # save a bit on method calls |
118 | my $txn_init_depth = $self->wrap_txn ? $self->storage->transaction_depth : undef; |
119 | my $txn_begin_ok; |
120 | |
121 | my $run_err = ''; |
122 | |
9345b14c |
123 | return preserve_context { |
ddcc02d1 |
124 | dbic_internal_try { |
9345b14c |
125 | if (defined $txn_init_depth) { |
7d534e68 |
126 | $self->storage->txn_begin; |
9345b14c |
127 | $txn_begin_ok = 1; |
128 | } |
7d534e68 |
129 | $cref->( @$args ); |
9345b14c |
130 | } catch { |
131 | $run_err = $_; |
132 | (); # important, affects @_ below |
133 | }; |
134 | } replace => sub { |
135 | my @res = @_; |
136 | |
7d534e68 |
137 | my $storage = $self->storage; |
9345b14c |
138 | |
729656c5 |
139 | if ( |
140 | defined $txn_init_depth |
141 | and |
142 | ! is_exception $run_err |
143 | and |
144 | defined( my $cur_depth = $storage->transaction_depth ) |
145 | ) { |
9345b14c |
146 | my $delta_txn = (1 + $txn_init_depth) - $cur_depth; |
147 | |
148 | if ($delta_txn) { |
149 | # a rollback in a top-level txn_do is valid-ish (seen in the wild and our own tests) |
150 | carp (sprintf |
151 | 'Unexpected reduction of transaction depth by %d after execution of ' |
152 | . '%s, skipping txn_commit()', |
153 | $delta_txn, |
7d534e68 |
154 | $cref, |
9345b14c |
155 | ) unless $delta_txn == 1 and $cur_depth == 0; |
156 | } |
157 | else { |
ddcc02d1 |
158 | dbic_internal_try { |
159 | $storage->txn_commit; |
160 | 1; |
161 | } |
162 | catch { |
163 | $run_err = $_; |
164 | }; |
9345b14c |
165 | } |
166 | } |
167 | |
168 | # something above threw an error (could be the begin, the code or the commit) |
841efcb3 |
169 | if ( is_exception $run_err ) { |
9345b14c |
170 | |
84efb6d7 |
171 | # Attempt a rollback if we did begin in the first place |
172 | # Will append rollback error if possible |
173 | $storage->__delicate_rollback( \$run_err ) |
174 | if $txn_begin_ok; |
9345b14c |
175 | |
7d534e68 |
176 | push @{ $self->exception_stack }, $run_err; |
177 | |
178 | # this will throw if max_attempts is reached |
179 | $self->_set_failed_attempt_count($self->failed_attempt_count + 1); |
9345b14c |
180 | |
181 | # init depth of > 0 ( > 1 with AC) implies nesting - no retry attempt queries |
182 | $storage->throw_exception($run_err) if ( |
183 | ( |
184 | defined $txn_init_depth |
185 | and |
186 | # FIXME - we assume that $storage->{_dbh_autocommit} is there if |
187 | # txn_init_depth is there, but this is a DBI-ism |
188 | $txn_init_depth > ( $storage->{_dbh_autocommit} ? 0 : 1 ) |
d3a2e424 |
189 | ) |
190 | or |
191 | ! do { |
7db939de |
192 | local $self->storage->{_in_do_block_retry_handler} = 1 |
193 | unless $self->storage->{_in_do_block_retry_handler}; |
d3a2e424 |
194 | $self->retry_handler->($self) |
195 | } |
9345b14c |
196 | ); |
197 | |
9345b14c |
198 | # we got that far - let's retry |
7d534e68 |
199 | carp( sprintf 'Retrying %s (attempt %d) after caught exception: %s', |
200 | $cref, |
201 | $self->failed_attempt_count + 1, |
9345b14c |
202 | $run_err, |
7d534e68 |
203 | ) if $self->retry_debug; |
9345b14c |
204 | |
205 | $storage->ensure_connected; |
206 | # if txn_depth is > 1 this means something was done to the |
4a0eed52 |
207 | # original $dbh, otherwise we would not get past the preceding if() |
9345b14c |
208 | $storage->throw_exception(sprintf |
209 | 'Unexpected transaction depth of %d on freshly connected handle', |
210 | $storage->transaction_depth, |
211 | ) if (defined $txn_init_depth and $storage->transaction_depth); |
212 | |
7d534e68 |
213 | return $self->_run($cref, @$args); |
9345b14c |
214 | } |
215 | |
216 | return wantarray ? @res : $res[0]; |
217 | }; |
218 | } |
219 | |
a2bd3796 |
220 | =head1 FURTHER QUESTIONS? |
9345b14c |
221 | |
a2bd3796 |
222 | Check the list of L<additional DBIC resources|DBIx::Class/GETTING HELP/SUPPORT>. |
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223 | |
a2bd3796 |
224 | =head1 COPYRIGHT AND LICENSE |
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225 | |
a2bd3796 |
226 | This module is free software L<copyright|DBIx::Class/COPYRIGHT AND LICENSE> |
227 | by the L<DBIx::Class (DBIC) authors|DBIx::Class/AUTHORS>. You can |
228 | redistribute it and/or modify it under the same terms as the |
229 | L<DBIx::Class library|DBIx::Class/COPYRIGHT AND LICENSE>. |
9345b14c |
230 | |
231 | =cut |
232 | |
233 | 1; |