67 lines
2.0 KiB
Ruby
67 lines
2.0 KiB
Ruby
class TableMigrationHelper
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def self.read_only_table(table_name)
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ActiveRecord::Base.exec_sql <<-SQL
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CREATE OR REPLACE FUNCTION #{readonly_function_name(table_name)} RETURNS trigger AS $rro$
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BEGIN
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RAISE EXCEPTION 'Discourse: Table is read only';
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RETURN null;
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END
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$rro$ LANGUAGE plpgsql;
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SQL
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ActiveRecord::Base.exec_sql <<-SQL
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CREATE TRIGGER #{readonly_trigger_name(table_name)}
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BEFORE INSERT OR UPDATE OR DELETE OR TRUNCATE
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ON #{table_name}
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FOR EACH STATEMENT
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EXECUTE PROCEDURE #{readonly_function_name(table_name)};
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SQL
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end
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def self.delayed_drop(old_name:, new_name:, after_migration:, delay: nil, on_drop: nil)
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delay ||= Rails.env.production? ? 3600 : 0
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sql = <<~SQL
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SELECT 1
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FROM INFORMATION_SCHEMA.TABLES
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WHERE table_schema = 'public' AND
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EXISTS (
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SELECT 1
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FROM schema_migration_details
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WHERE name = :after_migration AND
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created_at <= (current_timestamp at time zone 'UTC' - interval :delay)
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)
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AND EXISTS (
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SELECT 1
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FROM INFORMATION_SCHEMA.TABLES
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WHERE table_schema = 'public' AND
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table_name = :new_name
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)
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LIMIT 1
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SQL
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if ActiveRecord::Base.exec_sql(sql, old_name: old_name,
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new_name: new_name,
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delay: "#{delay.to_i || 0} seconds",
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after_migration: after_migration).to_a.length > 0
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on_drop&.call
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ActiveRecord::Base.exec_sql("DROP TABLE IF EXISTS #{old_name}")
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ActiveRecord::Base.exec_sql <<~SQL
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DROP FUNCTION IF EXISTS #{readonly_function_name(old_name)} CASCADE;
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SQL
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end
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end
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private
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def self.readonly_function_name(table_name)
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"public.raise_#{table_name}_read_only()"
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end
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def self.readonly_trigger_name(table_name)
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"#{table_name}_read_only"
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end
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end
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