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::Exception; |
8 | use DBIx::Class::Carp; |
9 | use Context::Preserve 'preserve_context'; |
10 | use DBIx::Class::_Util qw(is_exception qsub); |
11 | use Scalar::Util qw(weaken blessed reftype); |
12 | use Try::Tiny; |
13 | |
7f9a3f70 |
14 | # DO NOT edit away without talking to riba first, he will just put it back |
15 | # BEGIN pre-Moo2 import block |
16 | BEGIN { |
17 | my $initial_fatal_bits = (${^WARNING_BITS}||'') & $warnings::DeadBits{all}; |
cbd7f87a |
18 | |
7f9a3f70 |
19 | local $ENV{PERL_STRICTURES_EXTRA} = 0; |
cbd7f87a |
20 | # load all of these now, so that lazy-loading does not escape |
21 | # the current PERL_STRICTURES_EXTRA setting |
22 | require Sub::Quote; |
23 | require Sub::Defer; |
24 | require Moo; |
25 | require Moo::Object; |
26 | require Method::Generate::Accessor; |
27 | require Method::Generate::Constructor; |
28 | |
29 | Moo->import; |
7f9a3f70 |
30 | ${^WARNING_BITS} &= ( $initial_fatal_bits | ~ $warnings::DeadBits{all} ); |
31 | } |
32 | # END pre-Moo2 import block |
33 | |
9345b14c |
34 | use namespace::clean; |
35 | |
36 | =head1 NAME |
37 | |
38 | DBIx::Class::Storage::BlockRunner - Try running a block of code until success with a configurable retry logic |
39 | |
40 | =head1 DESCRIPTION |
41 | |
42 | =head1 METHODS |
43 | |
44 | =cut |
45 | |
46 | has storage => ( |
47 | is => 'ro', |
48 | required => 1, |
49 | ); |
50 | |
51 | has wrap_txn => ( |
52 | is => 'ro', |
53 | required => 1, |
54 | ); |
55 | |
56 | # true - retry, false - rethrow, or you can throw your own (not catching) |
57 | has retry_handler => ( |
58 | is => 'ro', |
59 | required => 1, |
7f9a3f70 |
60 | isa => qsub q{ |
7d534e68 |
61 | (Scalar::Util::reftype($_[0])||'') eq 'CODE' |
9345b14c |
62 | or DBIx::Class::Exception->throw('retry_handler must be a CODE reference') |
7f9a3f70 |
63 | }, |
9345b14c |
64 | ); |
65 | |
66 | has retry_debug => ( |
67 | is => 'rw', |
7d534e68 |
68 | # use a sub - to be evaluated on the spot lazily |
7f9a3f70 |
69 | default => qsub '$ENV{DBIC_STORAGE_RETRY_DEBUG}', |
7d534e68 |
70 | lazy => 1, |
9345b14c |
71 | ); |
72 | |
7d534e68 |
73 | has max_attempts => ( |
9345b14c |
74 | is => 'ro', |
7d534e68 |
75 | default => 20, |
9345b14c |
76 | ); |
77 | |
7d534e68 |
78 | has failed_attempt_count => ( |
9345b14c |
79 | is => 'ro', |
7d534e68 |
80 | init_arg => undef, # ensures one can't pass the value in |
81 | writer => '_set_failed_attempt_count', |
82 | default => 0, |
9345b14c |
83 | lazy => 1, |
7f9a3f70 |
84 | trigger => qsub q{ |
f9080e45 |
85 | $_[0]->throw_exception( sprintf ( |
7d534e68 |
86 | 'Reached max_attempts amount of %d, latest exception: %s', |
87 | $_[0]->max_attempts, $_[0]->last_exception |
88 | )) if $_[0]->max_attempts <= ($_[1]||0); |
7f9a3f70 |
89 | }, |
9345b14c |
90 | ); |
91 | |
92 | has exception_stack => ( |
93 | is => 'ro', |
94 | init_arg => undef, |
95 | clearer => '_reset_exception_stack', |
7f9a3f70 |
96 | default => qsub q{ [] }, |
9345b14c |
97 | lazy => 1, |
98 | ); |
99 | |
100 | sub last_exception { shift->exception_stack->[-1] } |
101 | |
f9080e45 |
102 | sub throw_exception { shift->storage->throw_exception (@_) } |
103 | |
9345b14c |
104 | sub run { |
105 | my $self = shift; |
106 | |
9345b14c |
107 | $self->_reset_exception_stack; |
7d534e68 |
108 | $self->_set_failed_attempt_count(0); |
109 | |
110 | my $cref = shift; |
111 | |
112 | $self->throw_exception('run() requires a coderef to execute as its first argument') |
113 | if ( reftype($cref)||'' ) ne 'CODE'; |
114 | |
9345b14c |
115 | my $storage = $self->storage; |
116 | |
7d534e68 |
117 | return $cref->( @_ ) if ( |
118 | $storage->{_in_do_block} |
119 | and |
120 | ! $self->wrap_txn |
121 | ); |
9345b14c |
122 | |
123 | local $storage->{_in_do_block} = 1 unless $storage->{_in_do_block}; |
124 | |
7d534e68 |
125 | return $self->_run($cref, @_); |
9345b14c |
126 | } |
127 | |
128 | # this is the actual recursing worker |
129 | sub _run { |
7d534e68 |
130 | # internal method - we know that both refs are strong-held by the |
131 | # calling scope of run(), hence safe to weaken everything |
132 | weaken( my $self = shift ); |
133 | weaken( my $cref = shift ); |
9345b14c |
134 | |
7d534e68 |
135 | my $args = @_ ? \@_ : []; |
9345b14c |
136 | |
137 | # from this point on (defined $txn_init_depth) is an indicator for wrap_txn |
138 | # save a bit on method calls |
139 | my $txn_init_depth = $self->wrap_txn ? $self->storage->transaction_depth : undef; |
140 | my $txn_begin_ok; |
141 | |
142 | my $run_err = ''; |
143 | |
9345b14c |
144 | return preserve_context { |
145 | try { |
146 | if (defined $txn_init_depth) { |
7d534e68 |
147 | $self->storage->txn_begin; |
9345b14c |
148 | $txn_begin_ok = 1; |
149 | } |
7d534e68 |
150 | $cref->( @$args ); |
9345b14c |
151 | } catch { |
152 | $run_err = $_; |
153 | (); # important, affects @_ below |
154 | }; |
155 | } replace => sub { |
156 | my @res = @_; |
157 | |
7d534e68 |
158 | my $storage = $self->storage; |
9345b14c |
159 | my $cur_depth = $storage->transaction_depth; |
160 | |
9bea2000 |
161 | if (defined $txn_init_depth and ! is_exception $run_err) { |
9345b14c |
162 | my $delta_txn = (1 + $txn_init_depth) - $cur_depth; |
163 | |
164 | if ($delta_txn) { |
165 | # a rollback in a top-level txn_do is valid-ish (seen in the wild and our own tests) |
166 | carp (sprintf |
167 | 'Unexpected reduction of transaction depth by %d after execution of ' |
168 | . '%s, skipping txn_commit()', |
169 | $delta_txn, |
7d534e68 |
170 | $cref, |
9345b14c |
171 | ) unless $delta_txn == 1 and $cur_depth == 0; |
172 | } |
173 | else { |
174 | $run_err = eval { $storage->txn_commit; 1 } ? '' : $@; |
175 | } |
176 | } |
177 | |
178 | # something above threw an error (could be the begin, the code or the commit) |
841efcb3 |
179 | if ( is_exception $run_err ) { |
9345b14c |
180 | |
181 | # attempt a rollback if we did begin in the first place |
182 | if ($txn_begin_ok) { |
183 | # some DBDs go crazy if there is nothing to roll back on, perform a soft-check |
184 | my $rollback_exception = $storage->_seems_connected |
185 | ? (! eval { $storage->txn_rollback; 1 }) ? $@ : '' |
186 | : 'lost connection to storage' |
187 | ; |
188 | |
189 | if ( $rollback_exception and ( |
190 | ! defined blessed $rollback_exception |
191 | or |
192 | ! $rollback_exception->isa('DBIx::Class::Storage::NESTED_ROLLBACK_EXCEPTION') |
193 | ) ) { |
194 | $run_err = "Transaction aborted: $run_err. Rollback failed: $rollback_exception"; |
195 | } |
196 | } |
197 | |
7d534e68 |
198 | push @{ $self->exception_stack }, $run_err; |
199 | |
200 | # this will throw if max_attempts is reached |
201 | $self->_set_failed_attempt_count($self->failed_attempt_count + 1); |
9345b14c |
202 | |
203 | # init depth of > 0 ( > 1 with AC) implies nesting - no retry attempt queries |
204 | $storage->throw_exception($run_err) if ( |
205 | ( |
206 | defined $txn_init_depth |
207 | and |
208 | # FIXME - we assume that $storage->{_dbh_autocommit} is there if |
209 | # txn_init_depth is there, but this is a DBI-ism |
210 | $txn_init_depth > ( $storage->{_dbh_autocommit} ? 0 : 1 ) |
7d534e68 |
211 | ) or ! $self->retry_handler->($self) |
9345b14c |
212 | ); |
213 | |
9345b14c |
214 | # we got that far - let's retry |
7d534e68 |
215 | carp( sprintf 'Retrying %s (attempt %d) after caught exception: %s', |
216 | $cref, |
217 | $self->failed_attempt_count + 1, |
9345b14c |
218 | $run_err, |
7d534e68 |
219 | ) if $self->retry_debug; |
9345b14c |
220 | |
221 | $storage->ensure_connected; |
222 | # if txn_depth is > 1 this means something was done to the |
4a0eed52 |
223 | # original $dbh, otherwise we would not get past the preceding if() |
9345b14c |
224 | $storage->throw_exception(sprintf |
225 | 'Unexpected transaction depth of %d on freshly connected handle', |
226 | $storage->transaction_depth, |
227 | ) if (defined $txn_init_depth and $storage->transaction_depth); |
228 | |
7d534e68 |
229 | return $self->_run($cref, @$args); |
9345b14c |
230 | } |
231 | |
232 | return wantarray ? @res : $res[0]; |
233 | }; |
234 | } |
235 | |
a2bd3796 |
236 | =head1 FURTHER QUESTIONS? |
9345b14c |
237 | |
a2bd3796 |
238 | Check the list of L<additional DBIC resources|DBIx::Class/GETTING HELP/SUPPORT>. |
9345b14c |
239 | |
a2bd3796 |
240 | =head1 COPYRIGHT AND LICENSE |
9345b14c |
241 | |
a2bd3796 |
242 | This module is free software L<copyright|DBIx::Class/COPYRIGHT AND LICENSE> |
243 | by the L<DBIx::Class (DBIC) authors|DBIx::Class/AUTHORS>. You can |
244 | redistribute it and/or modify it under the same terms as the |
245 | L<DBIx::Class library|DBIx::Class/COPYRIGHT AND LICENSE>. |
9345b14c |
246 | |
247 | =cut |
248 | |
249 | 1; |