db: adding multi database support

README.rst

@@ -44,6 +44,16 @@ In the source directory (whether cloned or from the tarball) run
 bot. Alternately, you can just run the ``sopel.py`` file in the source
 directory.
 
+Database Support
+----------------
+Sopel leverages SQLAlchemy to support the following database types: SQLite,
+MySQL, PostgreSQL, MSSQL, Oracle, Firebird, and Sybase. By default Sopel will
+use a SQLite database in the current configuration directory, but alternative
+databases can be configured with the following config options: ``db_type``,
+``db_filename`` (SQLite only), ``db_driver``, ``db_user``, ``db_pass``,
+``db_host``, ``db_port``, and ``db_name``. You will need to manually install
+any packages (system or ``pip``) needed to make your chosen database work.
+
 Adding modules
 --------------
 The easiest place to put new modules is in ``~/.sopel/modules``. Some newer

requirements.txt

@@ -11,3 +11,5 @@ requests>=2.0.0,<3.0.0
 dnspython<2.0; python_version >= '2.7' and python_version < '3.0'
 dnspython<1.16.0; python_version == '3.3'
 dnspython<3.0; python_version >= '3.4'
+sqlalchemy<1.3; python_version == '3.3'
+sqlalchemy<1.4; python_version != '3.3'

sopel/config/core_section.py

@@ -108,8 +108,38 @@ class CoreSection(StaticSection):
     channels = ListAttribute('channels')
     """List of channels for the bot to join when it connects"""
 
+    db_type = ChoiceAttribute('db_type', choices=[
+        'sqlite', 'mysql', 'postgres', 'mssql', 'oracle', 'firebird', 'sybase'], default='sqlite')
+    """The type of database to use for Sopel's database.
+
+    mysql - pip install mysql-python (Python 2) or pip install mysqlclient (Python 3)
+    postgres - pip install psycopg2
+    mssql - pip install pymssql
+
+    See https://docs.sqlalchemy.org/en/latest/dialects/ for a full list of dialects"""
+
     db_filename = ValidatedAttribute('db_filename')
-    """The filename for Sopel's database."""
+    """The filename for Sopel's database. (SQLite only)"""
+
+    db_driver = ValidatedAttribute('db_driver')
+    """The driver for Sopel's database.
+    This is optional, but can be specified if user wants to use a different driver
+    https://docs.sqlalchemy.org/en/latest/core/engines.html"""
+
+    db_user = ValidatedAttribute('db_user')
+    """The user for Sopel's database."""
+
+    db_pass = ValidatedAttribute('db_pass')
+    """The password for Sopel's database."""
+
+    db_host = ValidatedAttribute('db_host')
+    """The host for Sopel's database."""
+
+    db_port = ValidatedAttribute('db_port')
+    """The port for Sopel's database."""
+
+    db_name = ValidatedAttribute('db_name')
+    """The name of Sopel's database."""
 
     default_time_format = ValidatedAttribute('default_time_format',
                                              default='%Y-%m-%d - %T%Z')