# Getting Started with GitHub Authentication

This guide explains how to set up authentication with GitHub for Prowler. The documentation covers credential retrieval processes for each supported authentication method.

## Prerequisites

- GitHub account
- Token creation permissions (organization-level access requires admin permissions)

## Authentication Methods

### 1. Personal Access Token (PAT)

Personal Access Tokens provide the simplest GitHub authentication method and support individual user authentication or testing scenarios.

#### How to Create a Personal Access Token

1. **Navigate to GitHub Settings**
    - Open [GitHub](https://github.com) and sign in
    - Click the profile picture in the top right corner
    - Select "Settings" from the dropdown menu

2. **Access Developer Settings**
    - Scroll down the left sidebar
    - Click "Developer settings"

3. **Generate New Token**
    - Click "Personal access tokens"
    - Select "Tokens (classic)"
    - Click "Generate new token"

4. **Configure Token Permissions**
    To enable Prowler functionality, configure the following scopes:
    - `repo`: Full control of private repositories
    - `read:org`: Read organization and team membership
    - `read:user`: Read user profile data
    - `read:discussion`: Read discussions
    - `read:enterprise`: Read enterprise data (if applicable)

5. **Copy and Store the Token**
    - Copy the generated token immediately (GitHub displays tokens only once)
    - Store tokens securely using environment variables

#### How to Use Personal Access Tokens

Choose one of the following methods:

**Command-line flag:**

```console
prowler github --personal-access-token your_token_here
```

**Environment variable:**

```console
export GITHUB_PERSONAL_ACCESS_TOKEN="your_token_here"
prowler github
```

### 2. OAuth App Token

OAuth Apps enable applications to act on behalf of users with explicit consent.

#### How to Create an OAuth App

1. **Navigate to Developer Settings**
    - Open GitHub Settings → Developer settings
    - Click "OAuth Apps"

2. **Register New Application**
    - Click "New OAuth App"
    - Complete the required fields:
        - **Application name**: Descriptive application name
        - **Homepage URL**: Application homepage
        - **Authorization callback URL**: User redirection URL after authorization

3. **Obtain Authorization Code**
    - Request authorization code (replace `{app_id}` with the application ID):
   ```
   https://github.com/login/oauth/authorize?client_id={app_id}
   ```

4. **Exchange Code for Token**
    - Exchange authorization code for access token (replace `{app_id}`, `{secret}`, and `{code}`):
   ```
   https://github.com/login/oauth/access_token?code={code}&client_id={app_id}&client_secret={secret}
   ```

#### How to Use OAuth Tokens

Choose one of the following methods:

**Command-line flag:**

```console
prowler github --oauth-app-token your_oauth_token
```

**Environment variable:**

```console
export GITHUB_OAUTH_APP_TOKEN="your_oauth_token"
prowler github
```

### 3. GitHub App Credentials

GitHub Apps provide the recommended integration method for accessing multiple repositories or organizations.

#### How to Create a GitHub App

1. **Navigate to Developer Settings**
    - Open GitHub Settings → Developer settings
    - Click "GitHub Apps"

2. **Create New GitHub App**
    - Click "New GitHub App"
    - Complete the required fields:
        - **GitHub App name**: Unique application name
        - **Homepage URL**: Application homepage
        - **Webhook URL**: Webhook payload URL (optional)
        - **Permissions**: Application permission requirements

3. **Configure Permissions**
    To enable Prowler functionality, configure these permissions:
    - **Repository permissions**:
        - Contents (Read)
        - Metadata (Read)
        - Pull requests (Read)
    - **Organization permissions**:
        - Members (Read)
        - Administration (Read)
    - **Account permissions**:
        - Email addresses (Read)

4. **Generate Private Key**
    - Scroll to the "Private keys" section after app creation
    - Click "Generate a private key"
    - Download the `.pem` file and store securely

5. **Record App ID**
    - Locate the App ID at the top of the GitHub App settings page

#### How to Install the GitHub App

1. **Install Application**
    - Navigate to GitHub App settings
    - Click "Install App" in the left sidebar
    - Select the target account/organization
    - Choose specific repositories or select "All repositories"

#### How to Use GitHub App Credentials

Choose one of the following methods:

**Command-line flags:**

```console
prowler github --github-app-id your_app_id --github-app-key /path/to/private-key.pem
```

**Environment variables:**

```console
export GITHUB_APP_ID="your_app_id"
export GITHUB_APP_KEY="private-key-content"
prowler github
```

## Best Practices

### Security Considerations

Implement the following security measures:

- **Secure Credential Storage**: Store credentials using environment variables instead of hardcoding tokens
- **Secrets Management**: Use dedicated secrets management systems in production environments
- **Regular Token Rotation**: Rotate tokens and keys regularly
- **Least Privilege Principle**: Grant only minimum required permissions
- **Permission Auditing**: Review and audit permissions regularly
- **Token Expiration**: Set appropriate expiration times for tokens
- **Usage Monitoring**: Monitor token usage and revoke unused tokens

### Authentication Method Selection

Choose the appropriate method based on use case:

- **Personal Access Token**: Individual use, testing, or simple automation
- **OAuth App Token**: Applications requiring user consent and delegation
- **GitHub App**: Production integrations, especially for organizations

## Troubleshooting Common Issues

### Insufficient Permissions
- Verify token/app has necessary scopes/permissions
- Check organization restrictions on third-party applications

### Token Expiration
- Confirm token has not expired
- Verify fine-grained tokens have correct resource access

### Rate Limiting
- GitHub implements API call rate limits
- Consider GitHub Apps for higher rate limits

### Organization Settings
- Some organizations restrict third-party applications
- Contact organization administrator if access is denied