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'; |
e2741c7f |
9 | use DBIx::Class::_Util qw( is_exception qsub dbic_internal_try dbic_internal_catch ); |
cbd7f87a |
10 | use Scalar::Util qw(weaken blessed reftype); |
0020e364 |
11 | use Moo; |
9345b14c |
12 | use namespace::clean; |
13 | |
14 | =head1 NAME |
15 | |
16 | DBIx::Class::Storage::BlockRunner - Try running a block of code until success with a configurable retry logic |
17 | |
18 | =head1 DESCRIPTION |
19 | |
20 | =head1 METHODS |
21 | |
22 | =cut |
23 | |
24 | has storage => ( |
25 | is => 'ro', |
26 | required => 1, |
27 | ); |
28 | |
29 | has wrap_txn => ( |
30 | is => 'ro', |
31 | required => 1, |
32 | ); |
33 | |
34 | # true - retry, false - rethrow, or you can throw your own (not catching) |
35 | has retry_handler => ( |
36 | is => 'ro', |
37 | required => 1, |
7f9a3f70 |
38 | isa => qsub q{ |
7d534e68 |
39 | (Scalar::Util::reftype($_[0])||'') eq 'CODE' |
9345b14c |
40 | or DBIx::Class::Exception->throw('retry_handler must be a CODE reference') |
7f9a3f70 |
41 | }, |
9345b14c |
42 | ); |
43 | |
44 | has retry_debug => ( |
45 | is => 'rw', |
7d534e68 |
46 | # use a sub - to be evaluated on the spot lazily |
7f9a3f70 |
47 | default => qsub '$ENV{DBIC_STORAGE_RETRY_DEBUG}', |
7d534e68 |
48 | lazy => 1, |
9345b14c |
49 | ); |
50 | |
7d534e68 |
51 | has max_attempts => ( |
9345b14c |
52 | is => 'ro', |
7d534e68 |
53 | default => 20, |
9345b14c |
54 | ); |
55 | |
7d534e68 |
56 | has failed_attempt_count => ( |
9345b14c |
57 | is => 'ro', |
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58 | init_arg => undef, # ensures one can't pass the value in |
59 | writer => '_set_failed_attempt_count', |
60 | default => 0, |
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61 | lazy => 1, |
7f9a3f70 |
62 | trigger => qsub q{ |
f9080e45 |
63 | $_[0]->throw_exception( sprintf ( |
7d534e68 |
64 | 'Reached max_attempts amount of %d, latest exception: %s', |
65 | $_[0]->max_attempts, $_[0]->last_exception |
66 | )) if $_[0]->max_attempts <= ($_[1]||0); |
7f9a3f70 |
67 | }, |
9345b14c |
68 | ); |
69 | |
70 | has exception_stack => ( |
71 | is => 'ro', |
72 | init_arg => undef, |
73 | clearer => '_reset_exception_stack', |
7f9a3f70 |
74 | default => qsub q{ [] }, |
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75 | lazy => 1, |
76 | ); |
77 | |
78 | sub last_exception { shift->exception_stack->[-1] } |
79 | |
f9080e45 |
80 | sub throw_exception { shift->storage->throw_exception (@_) } |
81 | |
9345b14c |
82 | sub run { |
83 | my $self = shift; |
84 | |
9345b14c |
85 | $self->_reset_exception_stack; |
7d534e68 |
86 | $self->_set_failed_attempt_count(0); |
87 | |
88 | my $cref = shift; |
89 | |
90 | $self->throw_exception('run() requires a coderef to execute as its first argument') |
91 | if ( reftype($cref)||'' ) ne 'CODE'; |
92 | |
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93 | my $storage = $self->storage; |
94 | |
7d534e68 |
95 | return $cref->( @_ ) if ( |
96 | $storage->{_in_do_block} |
97 | and |
98 | ! $self->wrap_txn |
99 | ); |
9345b14c |
100 | |
101 | local $storage->{_in_do_block} = 1 unless $storage->{_in_do_block}; |
102 | |
7d534e68 |
103 | return $self->_run($cref, @_); |
9345b14c |
104 | } |
105 | |
106 | # this is the actual recursing worker |
107 | sub _run { |
7d534e68 |
108 | # internal method - we know that both refs are strong-held by the |
109 | # calling scope of run(), hence safe to weaken everything |
110 | weaken( my $self = shift ); |
111 | weaken( my $cref = shift ); |
9345b14c |
112 | |
7d534e68 |
113 | my $args = @_ ? \@_ : []; |
9345b14c |
114 | |
115 | # from this point on (defined $txn_init_depth) is an indicator for wrap_txn |
116 | # save a bit on method calls |
117 | my $txn_init_depth = $self->wrap_txn ? $self->storage->transaction_depth : undef; |
118 | my $txn_begin_ok; |
119 | |
120 | my $run_err = ''; |
121 | |
9345b14c |
122 | return preserve_context { |
ddcc02d1 |
123 | dbic_internal_try { |
9345b14c |
124 | if (defined $txn_init_depth) { |
7d534e68 |
125 | $self->storage->txn_begin; |
9345b14c |
126 | $txn_begin_ok = 1; |
127 | } |
7d534e68 |
128 | $cref->( @$args ); |
e2741c7f |
129 | } dbic_internal_catch { |
9345b14c |
130 | $run_err = $_; |
131 | (); # important, affects @_ below |
132 | }; |
133 | } replace => sub { |
134 | my @res = @_; |
135 | |
7d534e68 |
136 | my $storage = $self->storage; |
9345b14c |
137 | |
729656c5 |
138 | if ( |
139 | defined $txn_init_depth |
140 | and |
141 | ! is_exception $run_err |
142 | and |
143 | defined( my $cur_depth = $storage->transaction_depth ) |
144 | ) { |
9345b14c |
145 | my $delta_txn = (1 + $txn_init_depth) - $cur_depth; |
146 | |
147 | if ($delta_txn) { |
148 | # a rollback in a top-level txn_do is valid-ish (seen in the wild and our own tests) |
149 | carp (sprintf |
150 | 'Unexpected reduction of transaction depth by %d after execution of ' |
151 | . '%s, skipping txn_commit()', |
152 | $delta_txn, |
7d534e68 |
153 | $cref, |
9345b14c |
154 | ) unless $delta_txn == 1 and $cur_depth == 0; |
155 | } |
156 | else { |
ddcc02d1 |
157 | dbic_internal_try { |
158 | $storage->txn_commit; |
159 | 1; |
160 | } |
e2741c7f |
161 | dbic_internal_catch { |
ddcc02d1 |
162 | $run_err = $_; |
163 | }; |
9345b14c |
164 | } |
165 | } |
166 | |
167 | # something above threw an error (could be the begin, the code or the commit) |
841efcb3 |
168 | if ( is_exception $run_err ) { |
9345b14c |
169 | |
84efb6d7 |
170 | # Attempt a rollback if we did begin in the first place |
171 | # Will append rollback error if possible |
172 | $storage->__delicate_rollback( \$run_err ) |
173 | if $txn_begin_ok; |
9345b14c |
174 | |
7d534e68 |
175 | push @{ $self->exception_stack }, $run_err; |
176 | |
177 | # this will throw if max_attempts is reached |
178 | $self->_set_failed_attempt_count($self->failed_attempt_count + 1); |
9345b14c |
179 | |
180 | # init depth of > 0 ( > 1 with AC) implies nesting - no retry attempt queries |
181 | $storage->throw_exception($run_err) if ( |
182 | ( |
183 | defined $txn_init_depth |
184 | and |
185 | # FIXME - we assume that $storage->{_dbh_autocommit} is there if |
186 | # txn_init_depth is there, but this is a DBI-ism |
187 | $txn_init_depth > ( $storage->{_dbh_autocommit} ? 0 : 1 ) |
d3a2e424 |
188 | ) |
189 | or |
190 | ! do { |
7db939de |
191 | local $self->storage->{_in_do_block_retry_handler} = 1 |
192 | unless $self->storage->{_in_do_block_retry_handler}; |
d3a2e424 |
193 | $self->retry_handler->($self) |
194 | } |
9345b14c |
195 | ); |
196 | |
9345b14c |
197 | # we got that far - let's retry |
7d534e68 |
198 | carp( sprintf 'Retrying %s (attempt %d) after caught exception: %s', |
199 | $cref, |
200 | $self->failed_attempt_count + 1, |
9345b14c |
201 | $run_err, |
7d534e68 |
202 | ) if $self->retry_debug; |
9345b14c |
203 | |
204 | $storage->ensure_connected; |
205 | # if txn_depth is > 1 this means something was done to the |
4a0eed52 |
206 | # original $dbh, otherwise we would not get past the preceding if() |
9345b14c |
207 | $storage->throw_exception(sprintf |
208 | 'Unexpected transaction depth of %d on freshly connected handle', |
209 | $storage->transaction_depth, |
210 | ) if (defined $txn_init_depth and $storage->transaction_depth); |
211 | |
7d534e68 |
212 | return $self->_run($cref, @$args); |
9345b14c |
213 | } |
214 | |
215 | return wantarray ? @res : $res[0]; |
216 | }; |
217 | } |
218 | |
a2bd3796 |
219 | =head1 FURTHER QUESTIONS? |
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220 | |
a2bd3796 |
221 | Check the list of L<additional DBIC resources|DBIx::Class/GETTING HELP/SUPPORT>. |
9345b14c |
222 | |
a2bd3796 |
223 | =head1 COPYRIGHT AND LICENSE |
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224 | |
a2bd3796 |
225 | This module is free software L<copyright|DBIx::Class/COPYRIGHT AND LICENSE> |
226 | by the L<DBIx::Class (DBIC) authors|DBIx::Class/AUTHORS>. You can |
227 | redistribute it and/or modify it under the same terms as the |
228 | L<DBIx::Class library|DBIx::Class/COPYRIGHT AND LICENSE>. |
9345b14c |
229 | |
230 | =cut |
231 | |
232 | 1; |