Cloudflare Tunnel Script

This bash script automates the creation and management of Cloudflare tunnels for exposing local applications to the internet. It simplifies the process of setting up a secure connection between your local server and Cloudflare's global network, allowing you to access your application via a custom domain.

Features

• Automated Tunnel Creation: Creates a new Cloudflare tunnel if one doesn't already exist with the specified name.
• Configuration File Generation: Automatically generates a cloudflared configuration file (cloudflared-<appname>.yml) with the necessary settings, including the tunnel ID, credentials file path, origin certificate path, and ingress rules.
• DNS Record Management: Checks for an existing DNS record for your subdomain and creates one if it doesn't exist. This script assumes you want a DNS record of type CNAME that points to the cloudflare tunnel.
• Background Execution with Logging: Runs the cloudflared tunnel process in the background and redirects standard output and standard error to a log file (<appname>-cloudflared.log).
• Process Management: Saves the process ID (PID) of the running tunnel in a file (<appname>-cloudflared.pid) for easy stopping and restarting.
• Process Verification: Checks to make sure the tunnel started successfully.
• Error Handling: Provides informative error messages and exits if required arguments are missing, the Cloudflare origin certificate is not found, tunnel creation fails, or tunnel startup fails.
• Existing Tunnel Management: The script provides the functionality to stop and restart running tunnels associated with the specified appname.

Prerequisites

• Cloudflare Account: You'll need a Cloudflare account and a domain registered with Cloudflare.
• Cloudflared: Install the cloudflared command-line tool. You can download it from the Cloudflare website.
• Cloudflare Origin Certificate: Authenticate with Cloudflare and download the origin certificate. This typically resides in ~/.cloudflared/cert.pem. You can obtain the certificate using: cloudflared tunnel login.

Usage

./cftunnel.sh <appname> <domain> <local-port>

• <appname>: The name of your application (used for the tunnel name, config file name, log file name, and subdomain). For instance, if your app is called "my-app", you would assign this to the appname.
• <domain>: Your domain (e.g., example.com).
• <local-port>: The port number your application is listening on locally (e.g., 3000).

Example:

./tunnel.sh myapp example.com 3000

This will:

1. Check for the Cloudflare origin certificate.
2. Create a tunnel named myapp-tunnel (if it doesn't exist) using the Cloudflare API.
3. Generate a configuration file named cloudflared-myapp.yml.
4. Create a DNS record for myapp.example.com (if it doesn't exist), pointing to the Cloudflare tunnel.
5. Start the tunnel in the background.
6. Save the PID of the tunnel process to myapp-cloudflared.pid.
7. Log tunnel output to myapp-cloudflared.log.

Script Breakdown

• Argument Parsing: Validates the presence of the required arguments (appname, domain, local-port).
• Certificate Check: Verifies the existence of the Cloudflare origin certificate file.
• Tunnel Existence Check: Determines if a tunnel with the specified name already exists using cloudflared tunnel list and grep.
• Tunnel Creation: Creates a new Cloudflare tunnel using cloudflared tunnel create.
• Configuration File Generation: Creates the cloudflared-<appname>.yml configuration file using a "here document" (cat << EOF ... EOF).
• DNS Record Creation: Creates the CNAME record to automatically route traffic.
• Tunnel Startup: Starts the cloudflared tunnel run command in the background using & and redirects standard output and standard error to a log file.
• PID Management: Saves the process ID to a file so the process can be managed easily.
• Logging: Redirects the tunnel's output to a file for debugging and monitoring.

Important Considerations

• Security: This setup relies on Cloudflare's security features. Keep your cloudflared tool and Cloudflare account secure.
• Dependencies: Ensure you have cloudflared installed and configured correctly.
• Firewall: Make sure your firewall allows traffic to your application on the specified <local-port>.
• Domain Configuration: Your domain's nameservers must be pointed to Cloudflare for this script to work correctly. This step is outside the scope of this script.
• Cleanup: If you delete the Cloudflare tunnel through the Cloudflare dashboard, you might need to manually delete the DNS record created by the script.
• Error Handling: It's recommended to improve the error handling to better catch and report unexpected issues.
• Stopping the Tunnel: If you want to stop the script you can do this with kill $(cat ${APPNAME}-cloudflared.pid).