This Gist provides examples of how to create and schedule cron jobs for monitoring purposes. It includes a Bash script and a Go application that both check the availability of `google.com` every 5 minutes.

README.md

Cron Job Examples: Bash and Golang

This repository contains two examples of how to monitor google.com every 5 minutes using a Bash script and a Go application.

---

1. Bash Script Execution Instructions

Create and Set Up the Script

1. Save the Bash script from check_google.sh in this repository.
2. Make it executable:

   chmod +x check_google.sh

Set Up a Cron Job

1. Open the crontab file:

   crontab -e

2. Add the following line to run the script every 5 minutes:

   */5 * * * * /path/to/check_google.sh >> /path/to/check_google.log 2>&1

Logs

The output of the script will be saved in check_google.log.

---

2. Golang Application Execution Instructions

Run the Go Application

Option 1: Run directly:

go run main.go >> go-cron-check.log 2>&1 &

Option 2: Build and execute the binary:

go build -o go-cron-check
./go-cron-check >> go-cron-check.log 2>&1 &

Logs

The output of the Go application will be saved in go-cron-check.log.

check_google.sh

#!/bin/bash
if ping -c 1 google.com &> /dev/null
then
    echo "$(date): google.com is reachable."
else
    echo "$(date): google.com is not reachable."
fi

main.go

package main

import (
    "fmt"
    "net/http"
    "time"

    "github.com/robfig/cron/v3"
)

func main() {
    c := cron.New()

    // Schedule a job to run every 5 minutes
    c.AddFunc("*/5 * * * *", func() {
        checkGoogle()
    })

    // Start the cron scheduler
    c.Start()

    // Keep the main goroutine alive
    select {}
}

func checkGoogle() {
    client := &http.Client{
        Timeout: 5 * time.Second,
    }

    resp, err := client.Get("https://www.google.com")
    if err != nil {
        fmt.Println(time.Now().Format(time.RFC3339), ": google.com is not reachable. Error:", err)
        return
    }
    defer resp.Body.Close()

    if resp.StatusCode == 200 {
        fmt.Println(time.Now().Format(time.RFC3339), ": google.com is reachable.")
    } else {
        fmt.Println(time.Now().Format(time.RFC3339), ": google.com returned status:", resp.StatusCode)
    }
}