health_check.info

Let’s break down what this script does in detail. The script is named health_check.sh, authored by GJS (homelab-alpha), and its purpose is to check the availability of a given URL using both HTTP and HTTPS protocols.

Here’s a detailed explanation:

Script Metadata link

• Filename: health_check.sh
• Author: GJS (homelab-alpha)
• Date: May 26, 2024
• Version: 1.0.1
• Description: This script checks the availability of a given URL using both HTTP and HTTPS protocols.
• RAW Script: health_check.sh

The script defines a function named health-check that performs the URL availability check. Let’s go through the script line by line.

Function Definition link

function health-check() {
  green="\e[32m"
  red="\e[31m"
  end="\e[0m"

The function health-check is defined here. Three variables, green, red, and end, are set to escape codes for colored output in the terminal (green for success, red for failure, and resetting to default color).

Checking for URL Argument link

  if [ -z "$1" ]; then
    echo "Please provide a URL to check."
    return 1
  fi

This block checks if the user has provided a URL as an argument. If not, it prints a message prompting the user to provide a URL and returns an exit status of 1, indicating an error.

URL and Protocols link

  url="$1"

  protocols=("https" "http")

The provided URL is assigned to the variable url. An array protocols is defined, containing the strings "https" and "http".

Loop Through Protocols link

  for protocol in "${protocols[@]}"; do
    if curl --head --silent --show-error --fail --location "$protocol://$url"; then
      echo -e "$protocol://$url is ${green}UP${end} and running."
      return 0
    fi
  done

The script loops through each protocol in the protocols array. For each protocol, it uses the curl command to send a HEAD request to the URL. The options used are:

• --head: Fetch only the headers.
• --silent: Silent mode, which reduces output.
• --show-error: Show errors if they occur.
• --fail: Fail silently (no output at all) on HTTP errors.
• --location: Follow redirects.

If the curl command succeeds (indicating the URL is accessible), it prints a message that the URL is UP, colored green, and returns an exit status of 0, indicating success.

If Both Protocols Fail link

  echo -e "Both https://$url and http://$url are ${red}DOWN${end}"
  return 1
}

If neither HTTP nor HTTPS versions of the URL are accessible, the script prints a message that both are DOWN, colored red, and returns an exit status of 1.

Conclusion link

The health_check.sh script is a straightforward Bash script that checks the availability of a URL using both HTTP and HTTPS protocols. It provides user-friendly output with color-coded messages to indicate whether the URL is up or down. By using curl with appropriate options, it efficiently handles the URL checking process. This script is handy for quick health checks of web services.