aswi2021jmsd-gitlab4/src/config/connection_provider.py @ 7ad820d0

import os
import sqlite3
from sqlite3 import Connection

from injector import Module, provider, singleton

from src.config.configuration import Configuration
from src.constants import DB_DIR, TEST_DATABASE_FILE, SCHEMA_SQL_FILE, VALUES_SQL_FILE
from src.utils.file_anchor import FileAnchor
from src.utils.logger import Logger


class ConnectionProvider(Module):
    """
    Dependency injection module that provides database connection singleton
    """

    @singleton
    @provider
    def connect(self, configuration: Configuration) -> Connection:
        """
        Create an SQLite connection based on the given configuration
        :param configuration: Configuration class with application config data
        :return: connection singleton
        """

        Logger.debug(f"Creating a database connection [{configuration.connection_string}].")

        try:
            if not os.path.exists(FileAnchor(configuration.root_dir, DB_DIR).shortest_relative_path()) and \
                    configuration.connection_string != TEST_DATABASE_FILE:
                os.makedirs(FileAnchor(configuration.root_dir, DB_DIR).shortest_relative_path())

            co = sqlite3.connect(database=configuration.connection_string, check_same_thread=False)
            cu = co.cursor()

            schema_sql_file = open(FileAnchor(configuration.root_dir, SCHEMA_SQL_FILE).shortest_relative_path())
            schema_sql = schema_sql_file.read()

            values_sql_file = open(FileAnchor(configuration.root_dir, VALUES_SQL_FILE).shortest_relative_path())
            values_sql = values_sql_file.read()

            cu.executescript(schema_sql)
            cu.executescript(values_sql)
        except sqlite3.Error as e:
            Logger.error(f"Unknown error during database setting.")
            raise e

        return co