# Image Support Files

This directory contains helper scripts that enable NVM (Node Version Manager) functionality in Docker images.

## Files

### bash-with-nvm

A wrapper script used as the SHELL directive in Dockerfiles. It loads NVM before executing any RUN command, enabling commands like:

```dockerfile
SHELL ["/usr/local/bin/bash-with-nvm"]
RUN nvm install 18
RUN node --version
```

### docker-entrypoint.sh

An entrypoint script that ensures NVM is available at runtime. It handles:

1. Loading NVM environment on container start
2. Special handling for `bash -c` commands (common in CI/CD) to inject bashrc sourcing

## Usage

These files are copied into Alpine-based Docker images:

```dockerfile
COPY image_support_files/bash-with-nvm /usr/local/bin/bash-with-nvm
COPY image_support_files/docker-entrypoint.sh /usr/local/bin/docker-entrypoint.sh
RUN chmod +x /usr/local/bin/bash-with-nvm /usr/local/bin/docker-entrypoint.sh

SHELL ["/usr/local/bin/bash-with-nvm"]
ENTRYPOINT ["/usr/local/bin/docker-entrypoint.sh"]
```

## Why These Scripts Are Needed

NVM is a bash function, not a binary. This creates challenges in Docker:

1. **Build time**: Each RUN command starts a fresh shell without NVM loaded
2. **Runtime**: Container commands don't automatically have NVM available
3. **CI/CD**: Non-interactive shells (bash -c) need special handling

These scripts solve all three contexts.

## Maintenance

When updating NVM version, ensure compatibility with both scripts. The NVM_DIR path (`/usr/local/nvm`) must match across:
- These scripts
- Dockerfile ENV declarations
- /etc/bash.bashrc configuration