Source code for provy.more.centos.database.postgresql

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

'''
Roles in this namespace are meant to provide `PostgreSQL <http://www.postgresql.org/>`_ database management utilities for CentOS distributions.
'''
import re

import fabric

from provy.more.base.database import BasePostgreSQLRole
from provy.more.centos.package.yum import YumRole


class PostgreSQLRole(BasePostgreSQLRole):
    '''
    This role provides `PostgreSQL <http://www.postgresql.org/>`_ database management utilities for CentOS distributions.

    Take a look at :class:`provy.more.base.database.postgresql.BasePostgreSQLRole` for more available methods.

    Example:
    ::

        from provy.core import Role
        from provy.more.centos import PostgreSQLRole

        class MySampleRole(Role):
            def provision(self):
                with self.using(PostgreSQLRole) as role:
                    role.ensure_user("john")
                    role.ensure_database("foo", owner="john")
    '''
    def provision(self):
        '''
        Installs `PostgreSQL <http://www.postgresql.org/>`_ and its dependencies.
        This method should be called upon if overriden in base classes, or PostgreSQL won't work properly in the remote server.

        Example:
        ::

            class MySampleRole(Role):
                def provision(self):
                    self.provision_role(PostgreSQLRole) # no need to call this if using with block.
        '''
        with self.using(YumRole) as role:
            role.ensure_package_installed('postgresql-server')
            role.ensure_package_installed('postgresql-devel')

        self._ensure_initialized()
        self._ensure_running()
        self._run_on_startup()

    def _execute(self, *args, **kwargs):
        with fabric.api.cd('/var/lib/pgsql'):
            return super(PostgreSQLRole, self)._execute(*args, **kwargs)

    def _is_db_initialized(self):
        pgdata = '/var/lib/pgsql/data'
        return self.execute('ls -A %s' % pgdata, sudo=True, stdout=False)

    def _ensure_initialized(self):
        if not self._is_db_initialized():
            return(self.execute("service postgresql initdb", sudo=True))
        return True

    def _is_running(self):
        with fabric.api.settings(warn_only=True):
            status = self.execute('service postgresql status', sudo=True, stdout=False)
            return 'running' in status

    def _ensure_running(self):
        if not self._is_running():
            return self.execute('service postgresql start', sudo=True)
        return True

    def _will_start_on_boot(self):
        pkg_list = self.execute('chkconfig --list', sudo=True, stdout=False)
        return re.search(r'postgresql.*\t0:off\t1:off\t2:on\t3:on\t4:on\t5:on\t6:off', pkg_list)

    def _run_on_startup(self):
        if not self._will_start_on_boot():
            self.execute('chkconfig --add postgresql', sudo=True)
            self.execute('chkconfig postgresql on', sudo=True)
            return True
        return False