# Dockerize nodejs application

Deploying a **Node.js project using Docker from GitHub with a deploy key** involves a few main steps:

---

### Overview

1. **Generate and configure a deploy key** on GitHub.
    
2. **Write a Dockerfile** for your Node.js project.
    
3. **Create a Docker container or server environment** (e.g., a VPS or cloud instance).
    
4. **Configure SSH to use the deploy key to clone the private repository**
    
5. **Run Docker build and start the app.**
    

---

## 1. Create a Deploy Key on GitHub

Deploy keys are SSH keys associated with a **single repository**. This means they can only be used for cloning one repository.

### 1.1 Generate SSH Key (no passphrase)

```bash
ssh-keygen -t ED25519 -C "<yourcomment>" -f ./deploy_key_name
```

- You’ll get:
    
    - `deploy_key_name` (private)
        
    - `deploy_key_name.pub` (public)
        

### 1.2. Add Public Key to GitHub Repo

1. Go to **<GitHub repo> → Settings → Deploy keys**.
    
2. Click **"Add deploy key"**:
    
    - Title: anything (e.g., `Docker Deploy`)
        
    - Paste the **contents of `deploy_key.pub`**. this file can be opend using an text editor
        
    - ✅ Check **"Allow write access"** if your deployment needs the ability to push. Otherwise, leave it unchecked (Besic need for this totorial).
        
    - Save.
        

---

## 2. Create a Dockerfile

In your Node.js project (in GitHub), make sure you have a `Dockerfile` like this (basic configuration):

```Dockerfile
# Use Node base image
FROM node:lts-alpine

# Create app directory
WORKDIR /app

# Install dependencies
COPY backend/package*.json ./
RUN npm install

# Bundle app source
COPY backend/ .

# Expose port and start app
#EXPOSE 3000 #not needed if ports get exposed in the docker compose.
CMD [ "npm", "start" ]
```

---

## 3. Set up the Deployment Server

On your server (e.g., Ubuntu VPS):

### 3.1 Install Docker (if not installed):

```bash
curl -fsSL https://get.docker.com -o get-docker.sh
sh get-docker.sh
```

### 3.2 Copy the Private Deploy Key to the Server

```bash
scp deploy_key user@yourserver:/home/user/.ssh/deploy_key
```

Then, SSH into the server and set correct permissions:

```bash
chmod 600 ~/.ssh/deploy_key
```

---

## 4. Clone the GitHub Repo Using the Deploy Key

Since Git uses SSH, we need to **override the SSH config** so Git knows to use this key.

Create or modify `~/.ssh/config` on the server:

```bash
Host github_<projectname>
    HostName github.com
    User git
    IdentityFile ~/.ssh/deploy_key
    IdentitiesOnly yes
```

Then test:

```bash
ssh github_<projectname>
```

You should see something like:

```
Hi username/repo! You've successfully authenticated...
```

Now clone your private repo:

```bash
git clone github_projectname:yourusername/your-node-project.git
cd your-node-project
```

---

## 5. Build and Run Docker

### 5.1 Build the Docker Image

```bash
docker build -t my-node-app .
```

### 5.2 Run the Container

```bash
docker run -d -p 3000:3000 --name my-node-app-container my-node-app
```

Your app should now be running at `http://<your-server-ip>:3000`.

---

## Optional: Automate with a Shell Script

You could make a `deploy.sh`:

```bash
#!/bin/bash

# Ensure SSH agent is running and key is added
eval "$(ssh-agent -s)"
ssh-add ~/.ssh/deploy_key

# Clone/update the repo
if [ ! -d "your-node-project" ]; then
    git clone git@github.com:yourusername/your-node-project.git
else
    cd your-node-project
    git pull origin main
    cd ..
fi

# Build and run
cd your-node-project
docker build -t my-node-app .
docker stop my-node-app-container && docker rm my-node-app-container
docker run -d -p 3000:3000 --name my-node-app-container my-node-app
```

---

## Tips   
- Never commit deploy keys to your repo.
    

---

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