abstract global config setup

shared/selene/api/base_config.py

@@ -0,0 +1,81 @@
+"""Define configuration values that apply to all Mycroft Flask APIs
+
+The below base config classes included in this module represent globally
+applicable config values.  Please do not add to these classes unless the new
+config applies to ALL APIs. Define additional configs specific to an
+application within the application..
+
+Example usage:
+    in api.py:
+        from selene.api import get_environment_config
+        app.config = from_object(get_base_config())
+        app.config.update(<app_specific_configs>)
+        .
+        .
+        .
+        @app.teardown_teardown_appcontext
+        def close_db_connections():
+            app.config['DB_CONNECTION_POOL].close_all()
+
+"""
+
+import os
+
+from selene.util.db import allocate_db_connection_pool, DatabaseConnectionConfig
+
+db_connection_config = DatabaseConnectionConfig(
+    host=os.environ['DB_HOST'],
+    db_name=os.environ['DB_NAME'],
+    password=os.environ['DB_PASSWORD'],
+    port=os.environ.get('DB_PORT', 5432),
+    user=os.environ['DB_USER']
+)
+
+
+class APIConfigError(Exception):
+    pass
+
+
+class BaseConfig(object):
+    """Base configuration."""
+    ACCESS_SECRET = os.environ['JWT_ACCESS_SECRET']
+    DB_CONNECTION_POOL = allocate_db_connection_pool(db_connection_config)
+    DEBUG = False
+    REFRESH_SECRET = os.environ['JWT_REFRESH_SECRET']
+
+
+class DevelopmentConfig(BaseConfig):
+    DEBUG = True
+
+
+class TestConfig(BaseConfig):
+    pass
+
+
+class ProdConfig(BaseConfig):
+    pass
+
+
+def get_base_config():
+    """Determine which config object to pass to the application.
+
+    :return: an object containing the configs for the API.
+    """
+    environment_configs = dict(
+        dev=DevelopmentConfig,
+        test=TestConfig,
+        prod=ProdConfig
+    )
+
+    try:
+        environment_name = os.environ['SELENE_ENVIRONMENT']
+    except KeyError:
+        raise APIConfigError('the SELENE_ENVIRONMENT variable is not set')
+
+    try:
+        app_config = environment_configs[environment_name]
+    except KeyError:
+        error_msg = 'no configuration defined for the "{}" environment'
+        raise APIConfigError(error_msg.format(environment_name))
+
+    return app_config