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devcontainer-cli-port-forwarder

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Enable Port Forwarding when using DevContainer CLI

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forwarder.py
LICENSE
README.md

# Use via CDN

jsDelivr

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Example

Command Glossary

Commands referenced in this DOCs, explained below.

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`git clone`

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Clone an existing repository.

git clone {{remote_repository_location}} {{path/to/directory}}

Clone an existing repository into a new directory (the default directory is the repository name):

git clone --recursive {{remote_repository_location}}

Clone an existing repository and its submodules:

git clone {{[-n|--no-checkout]}} {{remote_repository_location}}

Clone only the `.git` directory of an existing repository:

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`socat`

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Multipurpose relay (SOcket CAT).

sudo socat - TCP-LISTEN:8080,fork

Listen to a port, wait for an incoming connection and transfer data to STDIO:

sudo socat OPENSSL-LISTEN:4433,reuseaddr,cert=./cert.pem,cafile=./ca.cert.pem,key=./key.pem,verify=0 STDOUT

Listen on a port using SSL and print to `stdout`:

sudo socat - TCP4:www.example.com:80

Create a connection to a host and port, transfer data in STDIO to connected host:

// repository documentation

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# 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.