1 package DBIx::Class::DeploymentHandler::DeployMethod::SQL::Translator;
4 # ABSTRACT: Manage your SQL and Perl migrations in nicely laid out directories
7 use Carp qw( carp croak );
8 use DBIx::Class::DeploymentHandler::LogImporter qw(:log :dlog);
14 require SQL::Translator::Diff;
16 require DBIx::Class::Storage; # loaded for type constraint
17 use DBIx::Class::DeploymentHandler::Types;
19 use Path::Class qw(file dir);
21 with 'DBIx::Class::DeploymentHandler::HandlesDeploy';
29 has force_overwrite => (
41 isa => 'DBIx::Class::Storage',
48 my $s = $self->schema->storage;
49 $s->_determine_driver;
53 has sql_translator_args => (
56 default => sub { {} },
58 has script_directory => (
67 isa => 'DBIx::Class::DeploymentHandler::Databases',
69 default => sub { [qw( MySQL SQLite PostgreSQL )] },
78 has schema_version => (
84 # this will probably never get called as the DBICDH
85 # will be passing down a schema_version normally, which
86 # is built the same way, but we leave this in place
87 sub _build_schema_version {
89 $self->schema->schema_version
92 sub __ddl_consume_with_prefix {
93 my ($self, $type, $versions, $prefix) = @_;
94 my $base_dir = $self->script_directory;
96 my $main = dir( $base_dir, $type );
98 dir( $base_dir, '_common', $prefix, join q(-), @{$versions} );
101 dir( $base_dir, '_common', $prefix, '_any' );
105 $dir = dir($main, $prefix, join q(-), @{$versions})
107 if ($self->ignore_ddl) {
110 croak "$main does not exist; please write/generate some SQL"
113 my $dir_any = dir($main, $prefix, '_any');
117 opendir my($dh), $dir;
119 map { $_ => "$dir/$_" }
120 grep { /\.(?:sql|pl|sql-\w+)$/ && -f "$dir/$_" }
124 die $_ unless $self->ignore_ddl;
126 for my $dirname (grep { -d $_ } $common, $common_any, $dir_any) {
127 opendir my($dh), $dirname;
128 for my $filename (grep { /\.(?:sql|pl)$/ && -f file($dirname,$_) } readdir $dh) {
129 unless ($files{$filename}) {
130 $files{$filename} = file($dirname,$filename);
136 return [@files{sort keys %files}]
139 sub _ddl_initialize_consume_filenames {
140 my ($self, $type, $version) = @_;
141 $self->__ddl_consume_with_prefix($type, [ $version ], 'initialize')
144 sub _ddl_schema_consume_filenames {
145 my ($self, $type, $version) = @_;
146 $self->__ddl_consume_with_prefix($type, [ $version ], 'deploy')
149 sub _ddl_protoschema_deploy_consume_filenames {
150 my ($self, $version) = @_;
151 my $base_dir = $self->script_directory;
153 my $dir = dir( $base_dir, '_source', 'deploy', $version);
154 return [] unless -d $dir;
156 opendir my($dh), $dir;
157 my %files = map { $_ => "$dir/$_" } grep { /\.yml$/ && -f "$dir/$_" } readdir $dh;
160 return [@files{sort keys %files}]
163 sub _ddl_protoschema_upgrade_consume_filenames {
164 my ($self, $versions) = @_;
165 my $base_dir = $self->script_directory;
167 my $dir = dir( $base_dir, '_preprocess_schema', 'upgrade', join q(-), @{$versions});
169 return [] unless -d $dir;
171 opendir my($dh), $dir;
172 my %files = map { $_ => "$dir/$_" } grep { /\.pl$/ && -f "$dir/$_" } readdir $dh;
175 return [@files{sort keys %files}]
178 sub _ddl_protoschema_downgrade_consume_filenames {
179 my ($self, $versions) = @_;
180 my $base_dir = $self->script_directory;
182 my $dir = dir( $base_dir, '_preprocess_schema', 'downgrade', join q(-), @{$versions});
184 return [] unless -d $dir;
186 opendir my($dh), $dir;
187 my %files = map { $_ => "$dir/$_" } grep { /\.pl$/ && -f "$dir/$_" } readdir $dh;
190 return [@files{sort keys %files}]
193 sub _ddl_protoschema_produce_filename {
194 my ($self, $version) = @_;
195 my $dirname = dir( $self->script_directory, '_source', 'deploy', $version );
196 $dirname->mkpath unless -d $dirname;
198 return "" . file( $dirname, '001-auto.yml' );
201 sub _ddl_schema_produce_filename {
202 my ($self, $type, $version) = @_;
203 my $dirname = dir( $self->script_directory, $type, 'deploy', $version );
204 $dirname->mkpath unless -d $dirname;
206 return "" . file( $dirname, '001-auto.sql' );
209 sub _ddl_schema_upgrade_consume_filenames {
210 my ($self, $type, $versions) = @_;
211 $self->__ddl_consume_with_prefix($type, $versions, 'upgrade')
214 sub _ddl_schema_downgrade_consume_filenames {
215 my ($self, $type, $versions) = @_;
216 $self->__ddl_consume_with_prefix($type, $versions, 'downgrade')
219 sub _ddl_schema_upgrade_produce_filename {
220 my ($self, $type, $versions) = @_;
221 my $dir = $self->script_directory;
223 my $dirname = dir( $dir, $type, 'upgrade', join q(-), @{$versions});
224 $dirname->mkpath unless -d $dirname;
226 return "" . file( $dirname, '001-auto.sql' );
229 sub _ddl_schema_downgrade_produce_filename {
230 my ($self, $type, $versions, $dir) = @_;
231 my $dirname = dir( $dir, $type, 'downgrade', join q(-), @{$versions} );
232 $dirname->mkpath unless -d $dirname;
234 return "" . file( $dirname, '001-auto.sql');
238 my ($self, $sql) = @_;
239 my $storage = $self->storage;
241 $sql = [ _split_sql_chunk( @$sql ) ];
243 Dlog_trace { "Running SQL $_" } $sql;
244 foreach my $line (@{$sql}) {
245 $storage->_query_start($line);
246 # the whole reason we do this is so that we can see the line that was run
248 $storage->dbh_do (sub { $_[1]->do($line) });
251 die "$_ (running line '$line')"
253 $storage->_query_end($line);
255 return join "\n", @$sql
258 # split a chunk o' SQL into statements
259 sub _split_sql_chunk {
260 my @sql = map { split /;\n/, $_ } @_;
264 s/^(?:BEGIN|BEGIN TRANSACTION|COMMIT).*//mgi;
280 return grep $_, @sql;
284 my ($self, $filename) = @_;
285 log_debug { "Running SQL from $filename" };
286 return $self->_run_sql_array($self->_read_sql_file($filename));
293 my $_package = $_file;
294 $_package =~ s/([^A-Za-z0-9_])/sprintf("_%2x", ord($1))/eg;
296 my $fn = eval sprintf <<'END_EVAL', $_package;
297 package DBICDH::Sandbox::%s;
300 $app ||= require $_file;
301 if ( !$app && ( my $error = $@ || $! )) { die $error; }
308 croak "$_file should define an anonymous sub that takes a schema but it didn't!"
309 unless ref $fn && ref $fn eq 'CODE';
315 my ($self, $filename, $versions) = @_;
316 log_debug { "Running Perl from $filename" };
318 my $fn = _load_sandbox($filename);
320 Dlog_trace { "Running Perl $_" } $fn;
322 $fn->($self->schema, $versions)
326 my ( $self, $code ) = @_;
327 return $code->() unless $self->txn_wrap;
329 my $guard = $self->schema->txn_scope_guard;
331 return preserve_context { $code->() } after => sub { $guard->commit };
334 sub _run_sql_and_perl {
335 my ($self, $filenames, $sql_to_run, $versions) = @_;
336 my @files = @{$filenames};
338 $self->_run_sql_array($sql_to_run) if $self->ignore_ddl;
340 my $sql = ($sql_to_run)?join ";\n", @$sql_to_run:'';
342 for my $filename (map file($_), @files) {
343 if ($self->ignore_ddl && $filename->basename =~ /^[^-]*-auto.*\.sql$/) {
345 } elsif ($filename =~ /\.sql$/) {
346 $sql .= $self->_run_sql($filename)
347 } elsif ( $filename =~ /\.pl$/ ) {
348 $self->_run_perl($filename, $versions)
350 croak "A file ($filename) got to deploy that wasn't sql or perl!";
360 my $version = (shift @_ || {})->{version} || $self->schema_version;
361 log_info { "deploying version $version" };
362 my $sqlt_type = $self->storage->sqlt_type;
364 my $sqltargs = $self->sql_translator_args;
365 if ($self->ignore_ddl) {
366 $sql = $self->_sql_from_yaml($sqltargs,
367 '_ddl_protoschema_deploy_consume_filenames', $sqlt_type
370 return $self->_run_sql_and_perl($self->_ddl_schema_consume_filenames(
373 ), $sql, [$version]);
379 my $version = $args->{version} || $self->schema_version;
380 log_info { "initializing version $version" };
381 my $storage_type = $args->{storage_type} || $self->storage->sqlt_type;
383 my @files = @{$self->_ddl_initialize_consume_filenames(
388 for my $filename (@files) {
389 # We ignore sql for now (till I figure out what to do with it)
390 if ( $filename =~ /^(.+)\.pl$/ ) {
391 my $filedata = do { local( @ARGV, $/ ) = $filename; <> };
393 no warnings 'redefine';
394 my $fn = eval "$filedata";
398 croak "$filename failed to compile: $@";
399 } elsif (ref $fn eq 'CODE') {
402 croak "$filename should define an anonymous sub but it didn't!";
405 croak "A file ($filename) got to initialize_scripts that wasn't sql or perl!";
410 sub _sqldiff_from_yaml {
411 my ($self, $from_version, $to_version, $db, $direction) = @_;
412 my $dir = $self->script_directory;
415 ignore_constraint_names => 1,
416 ignore_index_names => 1,
417 %{$self->sql_translator_args}
422 my $prefilename = $self->_ddl_protoschema_produce_filename($from_version, $dir);
424 # should probably be a croak
425 carp("No previous schema file found ($prefilename)")
426 unless -e $prefilename;
428 my $t = SQL::Translator->new({
432 parser => 'SQL::Translator::Parser::YAML',
435 my $out = $t->translate( $prefilename )
438 $source_schema = $t->schema;
440 $source_schema->name( $prefilename )
441 unless $source_schema->name;
446 my $filename = $self->_ddl_protoschema_produce_filename($to_version, $dir);
448 # should probably be a croak
449 carp("No next schema file found ($filename)")
452 my $t = SQL::Translator->new({
456 parser => 'SQL::Translator::Parser::YAML',
459 my $out = $t->translate( $filename )
462 $dest_schema = $t->schema;
464 $dest_schema->name( $filename )
465 unless $dest_schema->name;
468 my $transform_files_method = "_ddl_protoschema_${direction}_consume_filenames";
469 my $transforms = $self->_coderefs_per_files(
470 $self->$transform_files_method([$from_version, $to_version])
472 $_->($source_schema, $dest_schema) for @$transforms;
474 return [SQL::Translator::Diff::schema_diff(
482 my ($self, $sqltargs, $from_file, $db) = @_;
483 my $schema = $self->schema;
484 my $version = $self->schema_version;
488 my $actual_file = $self->$from_file($version);
489 for my $yaml_filename (@{(
490 DlogS_trace { "generating SQL from Serialized SQL Files: $_" }
491 (ref $actual_file?$actual_file:[$actual_file])
493 my $sqlt = SQL::Translator->new({
495 parser => 'SQL::Translator::Parser::YAML',
500 push @sql, $sqlt->translate($yaml_filename);
502 carp("Failed to translate to $db, skipping. (" . $sqlt->error . ")");
509 sub _prepare_install {
511 my $sqltargs = { %{$self->sql_translator_args}, %{shift @_} };
512 my $from_file = shift;
514 my $dir = $self->script_directory;
515 my $databases = $self->databases;
516 my $version = $self->schema_version;
518 foreach my $db (@$databases) {
519 my $sql = $self->_sql_from_yaml($sqltargs, $from_file, $db ) or next;
521 my $filename = $self->$to_file($db, $version, $dir);
523 if ($self->force_overwrite) {
524 carp "Overwriting existing DDL file - $filename";
527 die "Cannot overwrite '$filename', either enable force_overwrite or delete it"
530 open my $file, q(>), $filename;
531 print {$file} join ";\n", @$sql, '';
536 sub _resultsource_install_filename {
537 my ($self, $source_name) = @_;
539 my ($self, $type, $version) = @_;
540 my $dirname = dir( $self->script_directory, $type, 'deploy', $version );
541 $dirname->mkpath unless -d $dirname;
543 return "" . file( $dirname, "001-auto-$source_name.sql" );
547 sub _resultsource_protoschema_filename {
548 my ($self, $source_name) = @_;
550 my ($self, $version) = @_;
551 my $dirname = dir( $self->script_directory, '_source', 'deploy', $version );
552 $dirname->mkpath unless -d $dirname;
554 return "" . file( $dirname, "001-auto-$source_name.yml" );
558 sub install_resultsource {
559 my ($self, $args) = @_;
560 my $source = $args->{result_source}
561 or die 'result_source must be passed to install_resultsource';
562 my $version = $args->{version}
563 or die 'version must be passed to install_resultsource';
564 log_info { 'installing_resultsource ' . $source->source_name . ", version $version" };
565 my $rs_install_file =
566 $self->_resultsource_install_filename($source->source_name);
569 $self->$rs_install_file(
570 $self->storage->sqlt_type,
574 $self->_run_sql_and_perl($files, '', [$version]);
577 sub prepare_resultsource_install {
579 my $source = (shift @_)->{result_source};
580 log_info { 'preparing install for resultsource ' . $source->source_name };
582 my $install_filename = $self->_resultsource_install_filename($source->source_name);
583 my $proto_filename = $self->_resultsource_protoschema_filename($source->source_name);
584 $self->prepare_protoschema({
585 parser_args => { sources => [$source->source_name], }
587 $self->_prepare_install({}, $proto_filename, $install_filename);
591 log_info { 'preparing deploy' };
593 $self->prepare_protoschema({
594 # Exclude __VERSION so that it gets installed separately
598 grep { $_ ne '__VERSION' }
599 $self->schema->sources
602 }, '_ddl_protoschema_produce_filename');
603 $self->_prepare_install({}, '_ddl_protoschema_produce_filename', '_ddl_schema_produce_filename');
606 sub prepare_upgrade {
607 my ($self, $args) = @_;
609 "preparing upgrade from $args->{from_version} to $args->{to_version}"
611 $self->_prepare_changegrade(
612 $args->{from_version}, $args->{to_version}, $args->{version_set}, 'upgrade'
616 sub prepare_downgrade {
617 my ($self, $args) = @_;
619 "preparing downgrade from $args->{from_version} to $args->{to_version}"
621 $self->_prepare_changegrade(
622 $args->{from_version}, $args->{to_version}, $args->{version_set}, 'downgrade'
626 sub _coderefs_per_files {
627 my ($self, $files) = @_;
628 no warnings 'redefine';
629 [map eval do { local( @ARGV, $/ ) = $_; <> }, @$files]
632 sub _prepare_changegrade {
633 my ($self, $from_version, $to_version, $version_set, $direction) = @_;
634 my $schema = $self->schema;
635 my $databases = $self->databases;
636 my $dir = $self->script_directory;
638 my $schema_version = $self->schema_version;
639 my $diff_file_method = "_ddl_schema_${direction}_produce_filename";
640 foreach my $db (@$databases) {
641 my $diff_file = $self->$diff_file_method($db, $version_set, $dir );
643 if ($self->force_overwrite) {
644 carp("Overwriting existing $direction-diff file - $diff_file");
647 die "Cannot overwrite '$diff_file', either enable force_overwrite or delete it"
651 open my $file, q(>), $diff_file;
652 print {$file} join ";\n", @{$self->_sqldiff_from_yaml($from_version, $to_version, $db, $direction)};
658 my ($self, $file) = @_;
661 local $/ = undef; #sluuuuuurp
663 open my $fh, '<', $file;
664 return [ _split_sql_chunk( <$fh> ) ];
667 sub downgrade_single_step {
669 my $version_set = (shift @_)->{version_set};
670 Dlog_info { "downgrade_single_step'ing $_" } $version_set;
672 my $sqlt_type = $self->storage->sqlt_type;
674 if ($self->ignore_ddl) {
675 $sql_to_run = $self->_sqldiff_from_yaml(
676 $version_set->[0], $version_set->[1], $sqlt_type, 'downgrade',
679 my $sql = $self->_run_sql_and_perl($self->_ddl_schema_downgrade_consume_filenames(
682 ), $sql_to_run, $version_set);
687 sub upgrade_single_step {
689 my $version_set = (shift @_)->{version_set};
690 Dlog_info { "upgrade_single_step'ing $_" } $version_set;
692 my $sqlt_type = $self->storage->sqlt_type;
694 if ($self->ignore_ddl) {
695 $sql_to_run = $self->_sqldiff_from_yaml(
696 $version_set->[0], $version_set->[1], $sqlt_type, 'upgrade',
699 my $sql = $self->_run_sql_and_perl($self->_ddl_schema_upgrade_consume_filenames(
702 ), $sql_to_run, $version_set);
706 sub prepare_protoschema {
708 my $sqltargs = { %{$self->sql_translator_args}, %{shift @_} };
711 = $self->$to_file($self->schema_version);
713 # we do this because the code that uses this sets parser args,
714 # so we just need to merge in the package
715 my $sqlt = SQL::Translator->new({
716 parser => 'SQL::Translator::Parser::DBIx::Class',
717 producer => 'SQL::Translator::Producer::YAML',
721 my $yml = $sqlt->translate(data => $self->schema);
723 croak("Failed to translate to YAML: " . $sqlt->error)
727 if ($self->force_overwrite) {
728 carp "Overwriting existing DDL-YML file - $filename";
731 die "Cannot overwrite '$filename', either enable force_overwrite or delete it"
735 open my $file, q(>), $filename;
740 __PACKAGE__->meta->make_immutable;
744 # vim: ts=2 sw=2 expandtab
750 This class is the meat of L<DBIx::Class::DeploymentHandler>. It takes care
751 of generating serialized schemata as well as sql files to move from one
752 version of a schema to the rest. One of the hallmark features of this class
753 is that it allows for multiple sql files for deploy and upgrade, allowing
754 developers to fine tune deployment. In addition it also allows for perl
755 files to be run at any stage of the process.
757 For basic usage see L<DBIx::Class::DeploymentHandler::HandlesDeploy>. What's
758 documented here is extra fun stuff or private methods.
760 =head1 DIRECTORY LAYOUT
762 Arguably this is the best feature of L<DBIx::Class::DeploymentHandler>.
763 It's spiritually based upon L<DBIx::Migration::Directories>, but has a
764 lot of extensions and modifications, so even if you are familiar with it,
765 please read this. I feel like the best way to describe the layout is with
766 the following example:
792 | | `- 002-remove-customers.pl
795 | | `- 002-generate-customers.pl
797 | `- 999-bump-action.pl
804 | |- 001-create_database.pl
805 | `- 002-create_users_and_permissions.pl
813 So basically, the code
817 on an C<SQLite> database that would simply run
818 C<$sql_migration_dir/SQLite/deploy/1/001-auto.sql>. Next,
820 $dm->upgrade_single_step([1,2])
822 would run C<$sql_migration_dir/SQLite/upgrade/1-2/001-auto.sql> followed by
823 C<$sql_migration_dir/_common/upgrade/1-2/002-generate-customers.pl>, and
824 finally punctuated by
825 C<$sql_migration_dir/_common/upgrade/_any/999-bump-action.pl>.
827 C<.pl> files don't have to be in the C<_common> directory, but most of the time
828 they should be, because perl scripts are generally database independent.
830 Note that unlike most steps in the process, C<initialize> will not run SQL, as
831 there may not even be an database at initialize time. It will run perl scripts
832 just like the other steps in the process, but nothing is passed to them.
833 Until people have used this more it will remain freeform, but a recommended use
834 of initialize is to have it prompt for username and password, and then call the
835 appropriate C<< CREATE DATABASE >> commands etc.
837 =head2 Directory Specification
839 The following subdirectories are recognized by this DeployMethod:
843 =item C<_source> This directory can contain the following directories:
847 =item C<deploy> This directory merely contains directories named after schema
848 versions, which in turn contain C<yaml> files that are serialized versions
849 of the schema at that version. These files are not for editing by hand.
853 =item C<_preprocess_schema> This directory can contain the following
858 =item C<downgrade> This directory merely contains directories named after
859 migrations, which are of the form C<$from_version-$to_version>. Inside of
860 these directories you may put Perl scripts which are to return a subref
861 that takes the arguments C<< $from_schema, $to_schema >>, which are
862 L<SQL::Translator::Schema> objects.
864 =item C<upgrade> This directory merely contains directories named after
865 migrations, which are of the form C<$from_version-$to_version>. Inside of
866 these directories you may put Perl scripts which are to return a subref
867 that takes the arguments C<< $from_schema, $to_schema >>, which are
868 L<SQL::Translator::Schema> objects.
872 =item C<$storage_type> This is a set of scripts that gets run depending on what
873 your storage type is. If you are not sure what your storage type is, take a
874 look at the producers listed for L<SQL::Translator>. Also note, C<_common>
875 is a special case. C<_common> will get merged into whatever other files you
876 already have. This directory can contain the following directories itself:
880 =item C<initialize> Gets run before the C<deploy> is C<deploy>ed. Has the
881 same structure as the C<deploy> subdirectory as well; that is, it has a
882 directory for each schema version. Unlike C<deploy>, C<upgrade>, and C<downgrade>
883 though, it can only run C<.pl> files, and the coderef in the perl files get
884 no arguments passed to them.
886 =item C<deploy> Gets run when the schema is C<deploy>ed. Structure is a
887 directory per schema version, and then files are merged with C<_common> and run
888 in filename order. C<.sql> files are merely run, as expected. C<.pl> files are
889 run according to L</PERL SCRIPTS>.
891 =item C<upgrade> Gets run when the schema is C<upgrade>d. Structure is a directory
892 per upgrade step, (for example, C<1-2> for upgrading from version 1 to version
893 2,) and then files are merged with C<_common> and run in filename order.
894 C<.sql> files are merely run, as expected. C<.pl> files are run according
897 =item C<downgrade> Gets run when the schema is C<downgrade>d. Structure is a directory
898 per downgrade step, (for example, C<2-1> for downgrading from version 2 to version
899 1,) and then files are merged with C<_common> and run in filename order.
900 C<.sql> files are merely run, as expected. C<.pl> files are run according
908 Note that there can be an C<_any> in the place of any of the versions (like
909 C<1-2> or C<1>), which means those scripts will be run B<every> time. So if
910 you have an C<_any> in C<_common/upgrade>, that script will get run for every
915 A perl script for this tool is very simple. It merely needs to contain an
916 anonymous sub that takes a L<DBIx::Class::Schema> and the version set as it's
919 A very basic perl script might look like:
926 use DBIx::Class::DeploymentHandler::DeployMethod::SQL::Translator::ScriptHelpers
927 'schema_from_schema_loader';
929 schema_from_schema_loader({ naming => 'v4' }, sub {
932 # [1] for deploy, [1,2] for upgrade or downgrade, probably used with _any
933 my $versions = shift;
935 $schema->resultset('Users')->create({
941 Note that the above uses
942 L<DBIx::Class::DeploymentHanlder::DeployMethod::SQL::Translator::ScriptHelpers/schema_from_schema_loader>.
943 Using a raw coderef is strongly discouraged as it is likely to break as you
948 This attribute will, when set to true (default is false), cause the DM to use
949 L<SQL::Translator> to use the C<_source>'s serialized SQL::Translator::Schema
950 instead of any pregenerated SQL. If you have a development server this is
951 probably the best plan of action as you will not be putting as many generated
952 files in your version control. Goes well with with C<databases> of C<[]>.
954 =attr force_overwrite
956 When this attribute is true generated files will be overwritten when the
957 methods which create such files are run again. The default is false, in which
958 case the program will die with a message saying which file needs to be deleted.
962 The L<DBIx::Class::Schema> (B<required>) that is used to talk to the database
963 and generate the DDL.
967 The L<DBIx::Class::Storage> that is I<actually> used to talk to the database
968 and generate the DDL. This is automatically created with L</_build_storage>.
970 =attr sql_translator_args
972 The arguments that get passed to L<SQL::Translator> when it's used.
974 =attr script_directory
976 The directory (default C<'sql'>) that scripts are stored in
980 The types of databases (default C<< [qw( MySQL SQLite PostgreSQL )] >>) to
985 Set to true (which is the default) to wrap all upgrades and deploys in a single
990 The version the schema on your harddrive is at. Defaults to
991 C<< $self->schema->schema_version >>.
995 This class is an implementation of
996 L<DBIx::Class::DeploymentHandler::HandlesDeploy>. Pretty much all the
997 documentation is there.