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https://github.com/nohzafk/devcontainer-cli-port-forwarder

Enable Port Forwarding when using DevContainer CLI
https://github.com/nohzafk/devcontainer-cli-port-forwarder

devcontainer devcontainer-development devcontainers

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Enable Port Forwarding when using DevContainer CLI

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# DevContainer CLI Port Forwarder

# Overview
This Python script dynamically forward ports from a host machine to a Docker container according to `devcontainer.json` **forwardPorts**.

This Python script is created because currently DevContainer CLI does not support port forwarding, see [devcontainers/cli issue](https://github.com/devcontainers/cli/issues/22)

## Usage Context
- This script is only needed if you are managing your containers directly with the **devcontainer CLI**.
- If you are using vSCode with the Visual Studio Code Dev Containers extension,The VS Code extension already includes built-in support for port forwarding you do not need to use this script.

## Prerequisites
- host machine: Python 3 interpreter is installed.
- container: `socat` is installed.

## Features
- Dynamic Port Forwarding: Automates the process of forwarding specified ports from the host to a Docker container.
- Automatic Shutdown: The script automatically exits when the associated Docker container stops running.

# Installation
git clone this project under your project's `.devcontainer` directory, or anywhere you like.

```shell
git clone https://github.com/nohzafk/devcontainer-cli-port-forwarder.git .devcontainer/devcontainer-cli-port-forwarder
```

This script won't automatically install `socat` inside the container for you, you need to install `socat` inside the container.

you can simply add a line in **onCreateCommand** in your `devcontainer.json`

```json
"onCreateCommand": "sudo apt update && sudo apt install -y socat",
```

or use nix feature
```json
"features": {
"ghcr.io/devcontainers/features/nix:1": {
"packages": "socat"
}
},
```

# Usage
In your **devcontainer.json**, set the `initializeCommand` to run the script in the background when the container is being initialized:

```json
"initializeCommand": "python3 .devcontainer/devcontainer-cli-port-forwarder/forwarder.py &",
```

To enable verbose output, which provides more detailed information about the port forwarding process, modify the initializeCommand as follows:
```json
"initializeCommand": "python3 .devcontainer/devcontainer-cli-port-forwarder/forwarder.py verbose &",
```

and finally specify the ports that you want to forward from host by **forwardPorts**,

for example port 2222 used by devcontainer feature sshd `"ghcr.io/devcontainers/features/sshd:1": {},`

Use 'forwardPorts' to make a list of ports inside the container available locally.
```json
"forwardPorts": [2222],
```

Once configured in your devcontainer.json, the script will automatically start when you create a devcontainer using the devcontainer CLI. It listens on specified ports and forwards them to the Docker container.

- The script runs in the background and does not require manual intervention once started.
- When the Docker container stops, the script detects this and exits automatically, ensuring that resources are not left unnecessarily consumed on the host machine.