Integrated Tim's Gunicorn solution as replacement for Flask

src/api/app_utils.py

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+# Imports
+
+# > Standard library
+import logging
+import os
+from typing import Tuple
+
+# > Third-party dependencies
+from flask import request
+
+
+def setup_logging(level: str = "INFO") -> logging.Logger:
+    """
+    Set up logging with the specified level and return a logger instance.
+
+    Parameters
+    ----------
+    level : str, optional
+        Desired logging level. Supported values are "DEBUG", "INFO",
+        "WARNING", "ERROR". Default is "INFO".
+
+    Returns
+    -------
+    logging.Logger
+        Configured logger instance.
+    """
+
+    logging_levels = {
+        "DEBUG": logging.DEBUG,
+        "INFO": logging.INFO,
+        "WARNING": logging.WARNING,
+        "ERROR": logging.ERROR
+    }
+
+    # Set up the basic logging configuration
+    logging.basicConfig(
+        format="%(asctime)s - %(levelname)s - %(message)s",
+        datefmt="%d/%m/%Y %H:%M:%S",
+        level=logging_levels[level],
+    )
+
+    return logging.getLogger(__name__)
+
+
+def extract_request_data() -> Tuple[bytes, str, str]:
+    """
+    Extract image and other form data from the current request.
+
+    Returns
+    -------
+    tuple of (bytes, str, str)
+        image_content : bytes
+            Content of the uploaded image.
+        group_id : str
+            ID of the group from form data.
+        identifier : str
+            Identifier from form data.
+
+    Raises
+    ------
+    ValueError
+        If required data (image, group_id, identifier) is missing or if the
+        image format is invalid.
+    """
+
+    # Extract the uploaded image
+    image_file = request.files.get('image')
+    if not image_file:
+        raise ValueError("No image provided.")
+
+    # Validate image format
+    allowed_extensions = {'png', 'jpg', 'jpeg', 'gif'}
+    if '.' not in image_file.filename or image_file.filename.rsplit('.', 1)[1]\
+            .lower() not in allowed_extensions:
+        raise ValueError(
+            "Invalid image format. Allowed formats: png, jpg, jpeg, gif")
+
+    image_content = image_file.read()
+
+    # Extract other form data
+    group_id = request.form.get('group_id')
+    if not group_id:
+        raise ValueError("No group_id provided.")
+
+    identifier = request.form.get('identifier')
+    if not identifier:
+        raise ValueError("No identifier provided.")
+
+    return image_content, group_id, identifier
+
+
+def get_env_variable(var_name: str, default_value: str = None) -> str:
+    """
+    Retrieve an environment variable's value or use a default value.
+
+    Parameters
+    ----------
+    var_name : str
+        The name of the environment variable.
+    default_value : str, optional
+        Default value to use if the environment variable is not set.
+        Default is None.
+
+    Returns
+    -------
+    str
+        Value of the environment variable or the default value.
+
+    Raises
+    ------
+    ValueError
+        If the environment variable is not set and no default value is
+        provided.
+    """
+
+    logger = logging.getLogger(__name__)
+
+    value = os.environ.get(var_name)
+    if value is None:
+        if default_value is None:
+            raise ValueError(
+                f"Environment variable {var_name} not set and no default "
+                "value provided.")
+        logger.warning(
+            f"Environment variable {var_name} not set. Using default value: "
+            f"{default_value}")
+        return default_value
+
+    logger.debug(f"Environment variable {var_name} set to {value}")
+    return value