core/commands/base.py

#!/usr/bin/env python3
"""
Copyright (c) 2017-present, Facebook, Inc.
All rights reserved.

This source code is licensed under the BSD-style license found in the
LICENSE file in the root directory of this source tree.
"""

import logging

log = logging.getLogger(__name__)


class CommandBase(object):
    DESCRIPTION = """
    This is a default description. You should overwrite it in your sub-class.
    """

    # args from ArgumentParser.parse_args()
    args = None

    # master ArgumentParser
    parser = None

    # subparser for this command
    subparser = None

    def __init__(self, get_conn_func=None):
        """
        Initialize the command base object, and assign the infra-dependent
        stuffs if given

        @param get_mysql_connection: Override the function to get the MySQL
        connection. If not specified here, the default connection function
        will be used, which is 'osc.lib.db.default_get_mysql_connection'.
        If you want to customize the way OSC connect to a
        MySQL instance, you can write/import one in cli.py and pass it here
        @type: function
        """
        self.get_conn_func = get_conn_func
        self.init()

    def init(self):
        """
        Called upon init, override me.
        """
        pass

    def name(self):
        """
        Return the name of this subcommand.
        """
        return self.NAME

    def description(self):
        """
        Return a one-line description of this command
        Exceptions are ignored
        """
        return self.DESCRIPTION.splitlines()[0]

    def help(self):
        """
        Return a chunk of text explaining this command
        """
        return self.DESCRIPTION

    def setup_parser(
        self, parser, optional_db=False, require_user=False, require_password=False
    ):
        """
        Common parser shared across all the modes
        """
        parser.add_argument(
            "--socket", help="Socket file for the mysql " "connection", required=True
        )
        parser.add_argument(
            "--database",
            help="Database name(s) to run the schema change",
            nargs="+",
            required=(not optional_db),
        )
        parser.add_argument(
            "--repl-status",
            help="Force script to run only on instances with " "the replication role. ",
            choices=["master", "slave"],
        )
        parser.add_argument(
            "--mysql-user",
            help="MySQL username to connect to the instance",
            required=require_user,
        )
        parser.add_argument(
            "--mysql-password",
            help="MySQL user password to connect to the " "instance",
            required=require_password,
        )
        parser.add_argument(
            "--charset",
            default="ascii",
            help="Character set used for MySQL connection "
            "(defaults to '%(default)s').",
        )
        parser.add_argument(
            "--force",
            help="Ignore non-critical errors and continue "
            "making schema changes for all the given "
            "databases ",
        )

    def add_file_list_parser(self, parser):
        parser.add_argument(
            "--ddl-file-list",
            help="Files with CREATE statements. "
            "Multiple files are supported as list separated "
            "by space",
            required=True,
            nargs="+",
        )

    def add_engine_parser(self, parser):
        parser.add_argument(
            "--mysql-engine",
            help="Make sure the table is created with only " "the specified engine",
        )

    def usage(self, *args, **kwargs):
        self.parser.error(*args, **kwargs)

    def validate_args(self):
        pass