Docstrings, typing, a bit of renaming and minor stuff.

connections.py

@@ -0,0 +1,93 @@
+from typing import Union, Callable
+
+import mysql.connector
+import trino.dbapi
+from trino.auth import BasicAuthentication
+from trino.dbapi import connect
+
+
+def get_connection(connection_config: dict) -> Union[trino.dbapi.Connection]:
+    """
+    Pick the right way to build a connection and pass it the connection details.
+
+    :param connection_config: confi
+    :return:
+    """
+    connection_builder = pick_connection_builder(connection_config["engine"])
+    connection = connection_builder(connection_config)
+    return connection
+
+
+def get_possible_connection_builders() -> dict:
+    """
+    Get the complete list of connection builders.
+
+    :return: a dict where the keys are the strings that identify each
+    connection engine and the values are the callable function that will return
+    a valid connection object.
+    """
+    return {
+        "trino": get_connection_to_trino,
+        "mysql": get_connection_to_mysql,
+    }
+
+
+def pick_connection_builder(connection_engine_name: str) -> Callable:
+    """
+    Get a connection builder from a string name.
+
+    :param connection_engine_name: the string defining the connection engine.
+    :return: the connection builder function.
+    """
+    possible_connection_builders = get_possible_connection_builders()
+
+    try:
+        connection_builder = possible_connection_builders[connection_engine_name]
+    except KeyError:
+        raise ValueError(
+            f"Connection type {connection_engine_name} is unknown. Please review config."
+        )
+
+    return connection_builder
+
+
+def get_connection_to_trino(connection_config: dict) -> trino.dbapi.Connection:
+    """
+    Build a connection to Trino from the passed config.
+
+    :param connection_config: specifies host, port, etc.
+    :return: the connection object
+    """
+
+    return connect(
+        host=connection_config["host"],
+        port=connection_config["port"],
+        user=connection_config["user"],
+        auth=BasicAuthentication(
+            connection_config["user"],
+            connection_config["password"],
+        ),
+        http_scheme=connection_config["http_scheme"],
+        catalog=connection_config["catalog"],
+        schema=connection_config["schema"],
+    )
+
+
+def get_connection_to_mysql(
+    connection_config,
+) -> mysql.connector.connection.MySQLConnection:
+    """
+    Build a connection to MySQL from the passed config.
+
+    :param connection_config: specifies host, port, etc.
+    :return: the connection object
+    """
+    connection = mysql.connector.connect(
+        host=connection_config["host"],
+        port=connection_config["port"],
+        user=connection_config["user"],
+        password=connection_config["password"],
+        database=connection_config["schema"],
+    )
+
+    return connection