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我试图在运行 rails 迁移 ( rake db:migrate) 时捕获错误，以便它可以静默失败。

我想在我的 PostgreSQL 数据库上启用 RDKit 扩展，但前提是它在 PostgreSQL 安装中可用。我的rescue代码正在运行，但是 rake 仍然中止。我试过这个：

class EnableExtensionRdkit < ActiveRecord::Migration
  def up
    begin
      ActiveRecord::Base.connection.execute("CREATE EXTENSION rdkit;")
    rescue => error
      p "NO RDKit SUPPORT due to exception: "+error.to_s
  end
  def down
    ActiveRecord::Base.connection.execute("DROP EXTENSION IF EXISTS rdkit;")
  end
end

但我得到这个错误：

$ rake db:migrate
==  EnableExtensionRdkit: migrating ===========================================
NO RDKit SUPPORT due to exception: PG::UndefinedFile: ERROR:  could not access file "$libdir/rdkit": No such file or directory
: CREATE EXTENSION rdkit;
==  EnableExtensionRdkit: migrated (0.0955s) ==================================

rake aborted!
StandardError: An error has occurred, this and all later migrations canceled:

PG::InFailedSqlTransaction: ERROR:  current transaction is aborted, commands ignored until end of transaction block
:             SELECT attr.attname
            FROM pg_attribute attr
            INNER JOIN pg_constraint cons ON attr.attrelid = cons.conrelid AND attr.attnum = cons.conkey[1]
            WHERE cons.contype = 'p'
              AND cons.conrelid = '"schema_migrations"'::regclass
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.0.1/lib/active_record/connection_adapters/postgresql_adapter.rb:774:in `async_exec'
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.0.1/lib/active_record/connection_adapters/postgresql_adapter.rb:774:in `exec_no_cache'
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.0.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:138:in `block in exec_query'
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.0.1/lib/active_record/connection_adapters/abstract_adapter.rb:435:in `block in log'
/Library/Ruby/Gems/2.0.0/gems/activesupport-4.0.1/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.0.1/lib/active_record/connection_adapters/abstract_adapter.rb:430:in `log'
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1 回答 1

2

我找到了一种让它停止失败的方法。我怀疑关键字可能是“交易”。所以我disable_ddl_transaction!()在上面的EnableExtensionRdkit类中添加了。这解决了问题并给我留下了所需的输出：

$ rake db:migrate
==  EnableExtensionRdkit: migrating ===========================================
NO RDKit SUPPORT due to exception: PG::UndefinedFile: ERROR:  could not access file "$libdir/rdkit": No such file or directory
: CREATE EXTENSION rdkit;
==  EnableExtensionRdkit: migrated (0.0875s) ==================================

希望有人可以使用这个！

于 2014-07-31T10:18:55.600 回答