internet_connectivity.sh

#!/bin/bash

# URL to check for internet connectivity
URL="https://cp.cloudflare.com/generate_204"
INTERVAL=60  # Interval in seconds between checks
RETRIES=3  # Number of retries before concluding that the internet is down
RETRY_DELAY=1  # Delay in seconds between retries
CURL_TIMEOUT=1  # Curl timeout in seconds

# Function to check connectivity and measure latency
check_connectivity() {
    for ((i=1; i<=RETRIES; i++)); do
        timestamp=$(date "+%Y-%m-%d %H:%M:%S")
        ttfb=$(curl -o /dev/null --max-time $CURL_TIMEOUT --connect-timeout $CURL_TIMEOUT -s -w '%{time_starttransfer}\n' $URL)
        t=$(echo "scale=0; $ttfb*1000/1" | bc)
        t_int=$(printf "%.0f" "$t")
        http_code=$(curl -o /dev/null --max-time $CURL_TIMEOUT --connect-timeout $CURL_TIMEOUT -s -w '%{http_code}\n' $URL)

        # Ignore 0 ms latencies
        if [ "$ttfb" == "0" ]; then
            echo "Attempt $i/$RETRIES: Ignoring 0 ms latency."
            sleep $RETRY_DELAY
            continue
        fi

        if [ "$http_code" -eq 204 ]; then
            if [ "$t_int" -gt 1000 ]; then
                echo "😐😐😐 [$timestamp] Internet is slow! Time to first byte (latency): $t ms"
            else
                echo "😺😺😺 [$timestamp] Internet is up. Time to first byte (latency): $t ms"
            fi
            return
        else
            echo "Attempt $i/$RETRIES: 😡😡😡 [$timestamp] Internet is down or unstable."
            if [ "$i" -lt "$RETRIES" ]; then
                sleep $RETRY_DELAY
            fi
        fi
    done

    echo "😡😡😡 [$timestamp] Internet is down or unstable after $RETRIES retries."
}

# Continuously check connectivity
while true; do
    check_connectivity
    sleep $INTERVAL
done