def substitute_from_directives()

in dockerfiles.py [0:0]

• 23 lines of code
• 5 McCabe index (conditional complexity)

def substitute_from_directives(content: str, base_dir: str) -> str:
    """
    Recursively replace lines of the form:
        FROM identifier
    where 'identifier' is composed of letters and dashes, with the contents of
    <identifier>.Dockerfile found in 'base_dir'.

    Args:
        content (str): The Dockerfile content to process.
        base_dir (str): The directory containing base Dockerfiles to include.

    Returns:
        str: The processed Dockerfile content with all FROM directives substituted.
    """
    pattern = re.compile(r"^(FROM)\s+([A-Za-z-]+)\s*$")
    lines = content.splitlines()
    new_lines = []

    for line in lines:
        match = pattern.match(line)
        if match:
            identifier = match.group(2)
            file_path = os.path.join(base_dir, f"{identifier}.Dockerfile")
            if os.path.isfile(file_path):
                try:
                    with open(file_path, "r", encoding="utf-8") as inc_file:
                        included_content = inc_file.read()
                    # Recursively process the included file's content
                    substituted_content = substitute_from_directives(included_content, base_dir)
                    new_lines.append(substituted_content.rstrip())
                except OSError as e:
                    logger.error("Error reading included file '%s': %s", file_path, e)
                    new_lines.append(line)
            else:
                # If no file found, leave the line as is.
                new_lines.append(line)
        else:
            new_lines.append(line)

    return "\n".join(new_lines)