ResilientFTP

ResilientFTP is a robust Python library for handling FTP connections with automatic retry and reconnection logic. Built on top of Python's built-in ftplib and the powerful Tenacity retry library, ResilientFTP makes it easy to build resilient FTP clients that recover gracefully from transient errors and connection drops.

Features

• Automatic Reconnection: Checks the active connection using FTP’s NOOP command and reconnects if the connection is stale.

• Retry Logic with Exponential Backoff: Uses Tenacity to automatically retry FTP operations with customizable retry counts and backoff intervals.

• Robust Error Handling: Raises clear, domain-specific exceptions (e.g., FTPConnectionError) for easier debugging and maintenance.

• Context Manager Support: Use the FTP handler with Python’s with statement for automatic connection setup and cleanup.

• Customizable Behavior: Configure the number of retries, wait strategy, and logging to suit your production needs.

Installation

You can install ResilientFTP via pip (if published on PyPI):

pip install resilientftp

Alternatively, clone the repository and install locally:

git clone https://github.com/davidlorenzana/ResilientFTP.git
cd resilientftp
pip install .

Usage

Below are some examples of how to use ResilientFTP.

Basic Example

from resilientftp import FTP, FTPConnectionError

# Initialize the FTP handler with your server credentials and retry settings.
ftp = FTP("ftp.example.com", user="username", password="password", retries=5)

try:
    ftp.download_file("remote/path/file.txt", "local/path/file.txt")
    print("File downloaded successfully!")
except FTPConnectionError as e:
    print(f"FTP connection error: {e}")

Using Context Management

from resilientftp import FTP

# Using the context manager ensures proper connection cleanup.
with FTP("ftp.example.com", user="username", password="password", retries=5) as ftp:
    ftp.download_file("remote/path/file.txt", "local/path/file.txt")

Delegated FTP Commands

ResilientFTP supports delegating other FTP commands via __getattr__. For example:

# Access underlying FTP methods with automatic retry handling.
with FTP("ftp.example.com", user="username", password="password") as ftp:
    # For example, list files in a directory:
    files = ftp.nlst()
    print(files)

API Overview

FTP(host: str, user: Optional[str] = None, password: Optional[str] = None, retries: int = 5)

Initializes the FTP handler with the target FTP server, credentials, and the maximum number of retry attempts.

download_file(remote_path: str, local_path: str, expected_md5: Optional[str] = None) -> None

Downloads a file from the FTP server to the specified local path. If an expected_md5 is provided, the file is verified for integrity. Retries are automatically performed on transient errors.

__getattr__(attr: str) -> Any

Delegates attribute access to the underlying FTP connection, applying the same retry logic for transient errors.

Context Manager Methods

• __enter__() – Establishes the FTP connection.
• __exit__(exc_type, exc_val, exc_tb) – Ensures the FTP connection is gracefully closed.

Contributing

Contributions are welcome! Feel free to fork the repository, open issues, or submit pull requests. Please ensure your code adheres to PEP 8 standards and includes appropriate tests.

License

ResilientFTP is released under the MIT License. See the LICENSE file for details.

Acknowledgements

• Built on Python’s built-in ftplib.
• Uses Tenacity for robust retry handling.