Support .env.override file and remove env.example

Author: felixschndr

.env.example

@@ -2,4 +2,5 @@
 .idea
 **/__pycache__
 .env
+.env.override
 logs/

.gitignore

@@ -117,7 +117,6 @@ When the current time is a price minimum, the program wakes up and does the foll
    ```
 4. Create an `.env` and fill in your values
    ```bash
-   cp .env.example .env
    vi .env
    ```
 
@@ -143,6 +142,7 @@ When the current time is a price minimum, the program wakes up and does the foll
 
    All the environment variables are read in every time they are used.
    As a consequence, the program does **not** have to be restarted when they are altered.
+   If a `.env.override` exists values of the `.env` are overwritten.
 
 ### Running
 #### Manually
@@ -165,7 +165,6 @@ cd app/
 python -m venv .venv
 source .venv/bin/activate
 poetry install
-cp .env.example .env
 vi .env
 chown -R <username>: app/
 ```

README.md

@@ -1,27 +1,39 @@
 import os
 from typing import Any
 
-from dotenv import load_dotenv
+from dotenv import find_dotenv, load_dotenv
 
 
 class EnvironmentVariableGetter:
     @staticmethod
-    def get(name_of_variable: str, default_value: Any = None) -> str:
+    def get(name_of_variable: str, default_value: Any = None) -> bool | str:
         """
+        Gets the value of an environment variable.
+
+        The method attempts to retrieve the value of the provided environment variable. If the variable exists, it's
+        retrieved and, if applicable, converted to a boolean. If the variable doesn't exist, an optional default value
+        is returned. If neither the variable is set nor a default value is provided, it raises a RuntimeError.
+        The method also processes and gives precedence to variables defined in an `.env.override` file.
+
         Args:
-            name_of_variable: The name of the environment variable to be retrieved.
-            default_value: Optional; The default value to return if the environment variable is not set.
+            name_of_variable (str): The name of the environment variable to query.
+            default_value (Any, optional): The fallback value to return if the environment variable is not set.
 
         Returns:
-            The value of the environment variable cast to a boolean if possible, otherwise returns its string value or the default value.
+            bool | str: The retrieved environment variable value, either as a boolean (if applicable) or string.
 
         Raises:
-            RuntimeError: If the environment variable is not set and no default value is provided.
+            RuntimeError: If the specified environment variable is not found and no default value is provided.
         """
         load_dotenv(override=True)
 
+        # Load variables from .env.override with higher priority
+        load_dotenv(dotenv_path=find_dotenv(".env.override"), override=True)
+
         try:
             value = os.environ[name_of_variable]
+            if value == "":
+                raise KeyError()
             return EnvironmentVariableGetter._cast_string_to_bool(value)
         except KeyError:
             if default_value is not None: