ENR = Easy Nginx Redirects

CLI utility for quick & easy generating nginx configuration and running Docker containers with nginx reverse proxy.

Uses only Python standard library without external dependencies. So the utility works immediately after copying files - does not require installation of additional Python packages.

This utility demonstrates the capabilities of nginx's ngx_http_proxy_module using directives: proxy_pass, proxy_pass_header, proxy_intercept_errors, proxy_ssl_verify. These are the specific directives currently implemented, but ngx_http_proxy_module module offers many more options. The project serves as an example of a Python wrapper for automatic Docker container configuration and nginx-proxy integration, as well as building Python modules into a single executable script. You can fork this project and customize the nginx and Docker templates for your needs. Pull requests are welcome.

Table of Contents

• Table of Contents
• Use Cases
• Installation
  • Quick Installation
  • Other installation ways
    • Installation from source code
    • Notes about pipx
    • If GitHub is blocked in your network
• Usage
  • nginx-proxy Compatibility
    • Integration with nginx-proxy
    • Quick nginx-proxy deployment
• Under the Hood
  • Requirements
  • Dependencies
  • Generated Nginx Configuration
  • Docker Container Running
• Features & Roadmap
• Development & Contributing
  • Version Management
    • Versioning F.A.Q.
    • Versioning scheme
  • Pre-commit Hooks

Use Cases

• 🐳 One-click proxying for any local (Dockerized and non-Dockerized) or remote HTTP or HTTPS service. This tools runs proxy service as single docker container that is convenient to manage. Support docker networks and hostnames, host.docker.internal domain
• 🔒 Secure Access to Any Service. Make any web service accessible through HTTPS with just one command, even if it doesn't have security certificates
• 🏗️ Website Constructor Integration. Free domain binding for website builders like Tilda, Wix, Webflow, etc. Best for fully static sites, forms may require additional configuration
• 🔗 Custom Subdomain Links. Create short, easy-to-remember subdomain links using your own domain name instead of generic shortener services
• 😉 Your Own Everything. PRs and forks are welcome

Installation

Quick Installation

Since it uses only Python standard library without external dependencies you can install it via:

curl -fsSL --compressed https://raw.githubusercontent.com/pavelsr/enr/main/enr.pyz > /usr/local/bin/enr && \
    chmod +x /usr/local/bin/enr

or you can install it as regular Python module:

# pipx (recommended)
pipx install enr    # or from GitHub:
pipx install git+https://github.com/pavelsr/enr.git@main

# pip
pip install enr     # or from GitHub:
pip install git+https://github.com/pavelsr/enr.git@main

Other installation ways

Other installation ways

Installation from source code

git clone https://github.com/pavelsr/enr.git
cd enr
# Run without installation
./enr.py example.com http://localhost:3000
# Editable install (convenient for test and development):
pip install -e .
# Install development dependencies
pip install -e ".[dev]"
# Install using flit in development mode
flit install --symlink
# Creates enr.pyz from modules:
make build  # Creates enr.pyz from modules
# Or use flit directly
flit build

Notes about pipx

Since this is a CLI utility, it's recommended to install it using pipx to avoid conflicts with other Python packages:

# Install pipx if not already installed
python -m pip install --user pipx
python -m pipx ensurepath

# Install ENR
pipx install enr

Advantages of pipx installation:

• ✅ Isolated environment - no conflicts with other Python packages
• ✅ Easy updates - pipx upgrade enr
• ✅ Easy uninstall - pipx uninstall enr
• ✅ Global availability - enr command available everywhere

If GitHub is blocked in your network

You can copy the project manually using scp or rsync from a machine where GitHub is NOT blocked:

# Using scp, only enr.pyz
scp ./enr.pyz user@host.example.com:/usr/local/bin/enr

# Using scp, whole source code
ssh user@host.example.com "mkdir -p ~/enr" && scp -r * user@host.example.com:~/enr/

# Using rsync, whole source code (requires rsync on both machines)
rsync -avz . user@host.example.com:~/enr/

Note: Replace user@host.example.com with your actual server details. The rsync command automatically creates the 'enr' folder if it doesn't exist.

Usage

usage: enr [-h] [--port PORT] [--container-name CONTAINER_NAME] [--network NETWORK] [--config-dir CONFIG_DIR] [--dry-run] [--force] [--with-letsencrypt] [--version] server_name proxy_pass

positional arguments:
  server_name           Domain name for the server
  proxy_pass            Upstream server URL (e.g., http://localhost:3000)

options:
  -h, --help            show this help message and exit
  --port PORT, -p PORT  Port to listen on (default: 80)
  --container-name CONTAINER_NAME, -n CONTAINER_NAME
                        Docker container name (defaults to server_name)
  --network NETWORK     Docker network name (default: nginx-proxy)
  --config-dir CONFIG_DIR, -d CONFIG_DIR
                        Directory to save nginx config (default: current directory)
  --dry-run             Generate config only, don't run Docker container
  --force, -f           Force overwrite existing config file
  --with-letsencrypt    Automatically add Let's Encrypt environment variables for SSL support
  --version             Show version and exit

Examples:
enr example.com http://<container_name>:3000
enr example.com http://host.docker.internal:8000 --port 3000
enr example.com http://host.docker.internal:8000 --with-letsencrypt
enr shop.example.com https://marketplace.example/seller/<seller_id>
enr example.com https://example.tilda.ws --container-name my-tilda-proxy
enr test.com http://localhost:5000 --dry-run --config-dir ./configs --force

nginx-proxy Compatibility

ENR is specifically designed to work with nginx-proxy - a popular solution for automatic Docker container proxying. ENR automatically:

• Generates compatible nginx configurations
• Runs containers in the nginx-proxy network (by default)
• Sets the VIRTUAL_HOST environment variable for automatic discovery
• Adds Let's Encrypt variables for SSL certificates when using HTTPS

Integration with nginx-proxy

# Start nginx-proxy (if not already running)
docker run -d -p 80:80 -p 443:443 \
  --name nginx-proxy \
  --restart always \
  -v /var/run/docker.sock:/tmp/docker.sock:ro \
  nginxproxy/nginx-proxy

# Imagine that you have non-dockerized service running at 8000 port locally

# Using ENR with nginx-proxy
./enr.py example.com http://host.docker.internal:8000

Quick nginx-proxy deployment

For a complete example of nginx-proxy deployment with Let\x27s Encrypt support, see: 🔗 https://gitlab.com/pavelsr/nginx-proxy

This repository contains ready-to-use scripts for quick deployment of nginx-proxy with automatic SSL certificate management.

Under the Hood

Some Technical Overview about Architecture and Implementation Details

Requirements

• Python 3.11+ (recommended), 3.10+ (minimum)
• Docker

For full functionality, it is recommended to use:

• nginx-proxy - automatic Docker container proxying
• nginx-proxy-letsencrypt - automatic Let's Encrypt SSL certificates

Dependencies

The project has no external dependencies - uses only Python standard library:

• argparse - command line argument processing
• pathlib - file system path operations
• subprocess - running Docker commands
• str.format() - nginx configuration formatting (instead of jinja2)
• zipapp - building single script (instead of stickytape or PyInstaller)

Generated Nginx Configuration

The utility creates an nginx configuration of the following type:

server {
  server_name example.com;
  listen 80;

  location / {
    proxy_pass http://localhost:3000;
    proxy_pass_header Host;
    proxy_intercept_errors on;
    error_page 301 302 307 = @handle_redirect;
    # recursive_error_pages on;
  }

  location @handle_redirect {
    set $saved_redirect_location '$upstream_http_location';
    proxy_pass $saved_redirect_location;
  }
}

Docker Container Running

After generating the configuration, the utility runs a Docker container with the command:

# For HTTP
docker run --network nginx-proxy \
  -e VIRTUAL_HOST=example.com \
  -v $(pwd)/example.com.proxy.conf:/etc/nginx/conf.d/default.conf \
  --name example.com \
  -d --restart always nginx:alpine

# For HTTPS (Let's Encrypt variables are automatically added)
docker run --network nginx-proxy \
  -e VIRTUAL_HOST=example.com \
  -e LETSENCRYPT_HOST=example.com \
  -e LETSENCRYPT_EMAIL=443@example.com \
  -v $(pwd)/example.com.proxy.conf:/etc/nginx/conf.d/default.conf \
  --name example.com \
  -d --restart always nginx:alpine

Features & Roadmap

Implemented Features:

• Easy to use - one command to set up reverse proxy
• No external dependencies - only Python needed (recommended version 3.11)
• Single script - can be installed with one curl command, without git/pip/pipx
• Docker integration - automatic container running
• nginx-proxy integration - nginx-proxy automatically discover containers by VIRTUAL_HOST
• Automatic protocol addition - automatically adds http:// to domains without protocol
• Automatic arguments addition - automatically adds arguments for support host.docker.internal
• Automatic Let's Encrypt SSL support - automatically adds environment variables for HTTPS
• Named configurations - files are created as {server_name}.proxy.conf for better organization
• Single-source versionin - __init__.py
• Flit-based build system
• Zipapp-based single-file build

TODO (Roadmap):

• Nginx configs as named templates
• More high-level tests
• traefik and other proxy servers integration

Development & Contributing

All necessary development commands are available in the Makefile following best practices. To view the complete list of commands, run:

make help

Common Makefile commands

# Install development dependencies
make install-dev

# Install pre-commit hooks
make pre-commit-install

# Run all checks (formatting, linting, tests)
make check

# Or separately:
make format    # Code formatting
make lint      # Style checking
make test      # Run tests

# Pre-commit hooks
make pre-commit-run    # Manual pre-commit hooks run
make pre-commit-clean  # Clean pre-commit cache

# Clean temporary files
make clean

Git Guidelines

Before submitting a PR:

1. Squash your commits into a single, meaningful commit. E.g.

   git reset --soft HEAD~42
   git commit -m "feat: add new nginx configuration feature"

2. Use descriptive commit messages that explain what the change does

   E.g.

   git commit -m "fix: resolve docker container startup issue (#456)"

   Good practice: Include issue number if one exists (as shown in the example above)

FYI: I prefer trunk-based development rather than gitflow branching model

Version Management

To change version ONLY ONE STEP REQUIRED: Update version in __init__.py: __version__ = "x.y.z"

That's it! All other files automatically get the new version when you run:

• make build - builds single script with current version
• make build-dist - builds distribution packages with current version

Benefits of this approach

• Single source of truth: Version managed in ONE file only (__init__.py)
• Automatic propagation: All other files automatically get the version from this file
• Flit dynamic versioning: Uses flit's built-in dynamic = ["version"] feature
• No git dependency: Version management works independently of git tags
• No manual sync needed: Version is automatically read from module during build

Files that automatically get the version

pyenr/
├── enr/
│ └── init.py # ← MAIN VERSION FILE (change here ONLY)
├── pyproject.toml # ← gets version automatically via flit dynamic
├── setup.py # ← imports version from enr.init (legacy compatibility)
├── enr.pyz # ← single executable script (built via make build)
└── dist/ # ← packages get version automatically

Versioning F.A.Q.

Q: How to check current version? A: Run python -c "import enr; print(enr.__version__)"

Q: Version didn't update after changing version.py? A: Make sure to run make build or make build-dist after changing the version. Flit will automatically read the new version.

Q: Flit build failed? A: Make sure all files are committed to git, as flit requires a clean git state.

Versioning scheme

This project follows Semantic Versioning

Pre-commit Hooks

The project uses pre-commit hooks for automatic code quality checking before each commit

What is automatically checked:

• ✅ Single script build (make build)
• ✅ Code formatting (Black)
• ✅ Style checking (ruff)
• ✅ Test running (pytest)
• ✅ Automatic addition of changed enr.pyz to commit