73 lines
2.4 KiB
Ruby
73 lines
2.4 KiB
Ruby
class ColumnDropper
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def self.drop(table:, after_migration:, columns:, delay: nil, on_drop: nil)
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raise ArgumentError.new("Invalid table name passed to drop #{table}") if table =~ /[^a-z0-9_]/i
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columns.each do |column|
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raise ArgumentError.new("Invalid column name passed to drop #{column}") if column =~ /[^a-z0-9_]/i
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end
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delay ||= Rails.env.production? ? 60 : 0
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sql = <<~SQL
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SELECT 1
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FROM INFORMATION_SCHEMA.COLUMNS
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WHERE table_schema = 'public' AND
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table_name = :table AND
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column_name IN (:columns) 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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LIMIT 1
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SQL
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if ActiveRecord::Base.exec_sql(sql, table: table,
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columns: columns,
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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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columns.each do |column|
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# safe cause it is protected on method entry, can not be passed in params
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ActiveRecord::Base.exec_sql("ALTER TABLE #{table} DROP COLUMN IF EXISTS #{column}")
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ActiveRecord::Base.exec_sql <<~SQL
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DROP FUNCTION IF EXISTS #{readonly_function_name(table, column)};
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DROP TRIGGER IF EXISTS #{readonly_trigger_name(table, column)} ON #{table};
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SQL
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end
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end
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end
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def self.mark_readonly(table_name, column_name)
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ActiveRecord::Base.exec_sql <<-SQL
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CREATE OR REPLACE FUNCTION #{readonly_function_name(table_name, column_name)} RETURNS trigger AS $rcr$
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BEGIN
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RAISE EXCEPTION 'Discourse: #{column_name} in #{table_name} is readonly';
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END
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$rcr$ 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, column_name)}
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BEFORE INSERT OR UPDATE OF #{column_name}
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ON #{table_name}
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FOR EACH ROW
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WHEN (NEW.#{column_name} IS NOT NULL)
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EXECUTE PROCEDURE #{readonly_function_name(table_name, column_name)};
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SQL
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end
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private
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def self.readonly_function_name(table_name, column_name)
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"raise_#{table_name}_#{column_name}_readonly()"
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end
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def self.readonly_trigger_name(table_name, column_name)
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"#{table_name}_#{column_name}_readonly"
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end
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end
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