ansible/library/database/mysql_variables

#!/usr/bin/python
# -*- coding: utf-8 -*-

"""

Ansible module to manage mysql variables
(c) 2013, Balazs Pocze <banyek@gawker.com>
Certain parts are taken from Mark Theunissen's mysqldb module

This file is part of Ansible

Ansible is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

Ansible is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
"""

DOCUMENTATION = '''
---
module: mysql_variables

short_description: Manage MySQL global variables
description:
    - Query / Set MySQL variables
version_added: 1.3
options:
    variable:
        description:
            - Variable name to operate
        required: True
    value:
        description:
            - If set, then sets variable value to this
        required: False
    login_user:
        description:
            - username to connect mysql host, if defined login_password also needed.
        required: False
    login_password:
        description:
            - password to connect mysql host, if defined login_user also needed.
        required: False
    login_host:
        description:
            - mysql host to connect
        required: False
    login_unix_socket:
        description:
            - unix socket to connect mysql server
'''
EXAMPLES = '''
# Check for sync_binary_log setting
- mysql_variables: variable=sync_binary_log

# Set read_only variable to 1
- mysql_variables: variable=read_only value=1
'''


import ConfigParser
import os
import warnings

try:
    import MySQLdb
except ImportError:
    mysqldb_found = False
else:
    mysqldb_found = True


def getvariable(cursor, mysqlvar):
    cursor.execute("SHOW VARIABLES LIKE '" + mysqlvar + "'")
    mysqlvar_val = cursor.fetchall()
    return mysqlvar_val

def setvariable(cursor, mysqlvar, value):
    try:
        cursor.execute("SET GLOBAL " + mysqlvar + "=" + value)
        cursor.fetchall()
        result = True
    except Exception, e:
        result = str(e)
    return result


def strip_quotes(s):
    """ Remove surrounding single or double quotes

    >>> print strip_quotes('hello')
    hello
    >>> print strip_quotes('"hello"')
    hello
    >>> print strip_quotes("'hello'")
    hello
    >>> print strip_quotes("'hello")
    'hello

    """
    single_quote = "'"
    double_quote = '"'

    if s.startswith(single_quote) and s.endswith(single_quote):
        s = s.strip(single_quote)
    elif s.startswith(double_quote) and s.endswith(double_quote):
        s = s.strip(double_quote)
    return s


def config_get(config, section, option):
    """ Calls ConfigParser.get and strips quotes

    See: http://dev.mysql.com/doc/refman/5.0/en/option-files.html
    """
    return strip_quotes(config.get(section, option))


def load_mycnf():
    config = ConfigParser.RawConfigParser()
    mycnf = os.path.expanduser('~/.my.cnf')
    if not os.path.exists(mycnf):
        return False
    try:
        config.readfp(open(mycnf))
    except (IOError):
        return False
    # We support two forms of passwords in .my.cnf, both pass= and password=,
    # as these are both supported by MySQL.
    try:
        passwd = config_get(config, 'client', 'password')
    except (ConfigParser.NoOptionError):
        try:
            passwd = config_get(config, 'client', 'pass')
        except (ConfigParser.NoOptionError):
            return False

    # If .my.cnf doesn't specify a user, default to user login name
    try:
        user = config_get(config, 'client', 'user')
    except (ConfigParser.NoOptionError):
        user = getpass.getuser()
    creds = dict(user=user, passwd=passwd)
    return creds


def main():
    module = AnsibleModule(
            argument_spec = dict(
            login_user=dict(default=None),
            login_password=dict(default=None),
            login_host=dict(default="localhost"),
            login_unix_socket=dict(default=None),
            variable=dict(default=None),
            value=dict(default=None)

        )
    )
    user = module.params["login_user"]
    password = module.params["login_password"]
    host = module.params["login_host"]
    mysqlvar = module.params["variable"]
    value = module.params["value"]
    if not mysqldb_found:
        module.fail_json(msg="the python mysqldb module is required")
    else:
        warnings.filterwarnings('error', category=MySQLdb.Warning)

    # Either the caller passes both a username and password with which to connect to
    # mysql, or they pass neither and allow this module to read the credentials from
    # ~/.my.cnf.
    login_password = module.params["login_password"]
    login_user = module.params["login_user"]
    if login_user is None and login_password is None:
        mycnf_creds = load_mycnf()
        if mycnf_creds is False:
            login_user = "root"
            login_password = ""
        else:
            login_user = mycnf_creds["user"]
            login_password = mycnf_creds["passwd"]
    elif login_password is None or login_user is None:
        module.fail_json(msg="when supplying login arguments, both login_user and login_password must be provided")
    try:
        if module.params["login_unix_socket"]:
            db_connection = MySQLdb.connect(host=module.params["login_host"], unix_socket=module.params["login_unix_socket"], user=login_user, passwd=login_password, db="mysql")
        else:
            db_connection = MySQLdb.connect(host=module.params["login_host"], user=login_user, passwd=login_password, db="mysql")
        cursor = db_connection.cursor()
    except Exception, e:
        module.fail_json(msg="unable to connect to database, check login_user and login_password are correct or ~/.my.cnf has the credentials")
    if mysqlvar is None:
        module.fail_json(msg="Cannot run without variable to operate with")
    mysqlvar_val = getvariable(cursor, mysqlvar)
    if value is None:
        module.exit_json(msg=mysqlvar_val)
    else:
        if value == mysqlvar_val[0][1]:
            module.exit_json(msg="Variable already set to requested value", changed=False)
        result = setvariable(cursor, mysqlvar, value)
        if result is True:
            module.exit_json(msg="Variable change succeeded", changed=True)
        else:
            module.fail_json(msg=result, changed=False)

# this is magic, see lib/ansible/module_common.py
#<<INCLUDE_ANSIBLE_MODULE_COMMON>>
main()