Setting Up Automatic Cloudflare DNS Updates with Cron

cloudflare.sh

#!/bin/bash

auth_email="example@gmail.com" # The email used to login 'https://dash.cloudflare.com'
auth_key="YOUR_KEY" # Top right corner, "My profile" > "Global API Key"
zone_identifier="YOUR_ZONE_ID" # Can be found in the "Overview" tab of your domain, Zone ID is at the right bottom
record_names=("www.example.com" "example.com") # List of records you want to be synced
proxy=false # Set the proxy to true or false

log_file="$(dirname "$0")/update-logs.log"
ip_file="$(dirname "$0")/current_ip.txt"

# Ensure the log file is writable
if [ ! -e "$log_file" ]; then
  touch "$log_file"
fi
chmod 664 "$log_file"

# Ensure the IP file exists
if [ ! -e "$ip_file" ]; then
  touch "$ip_file"
fi

###########################################
## Function to log messages with timestamp
###########################################
log_message() {
  local message=$1
  local timestamp=$(date +"%Y-%m-%d %H:%M:%S")
  echo -e "[$timestamp] $message" | tee -a "$log_file"
}

###########################################
## Check if we have a public IP
###########################################
ip=$(curl -s https://ipv4.icanhazip.com/ || curl -s https://api.ipify.org)
if [ -z "$ip" ]; then
  log_message "No public IP found."
  exit 1
fi

###########################################
## Check if the IP has changed
###########################################
stored_ip=$(cat "$ip_file")
if [ "$ip" == "$stored_ip" ]; then
  log_message "IP has not changed. Current IP: $ip"
  exit 0
fi

###########################################
## Function to update DNS record
###########################################
update_record() {
  local record_name=$1

  ###########################################
  ## Seek for the A record
  ###########################################
  log_message "Check Initiated for $record_name"
  record=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones/$zone_identifier/dns_records?name=$record_name" -H "X-Auth-Email: $auth_email" -H "X-Auth-Key: $auth_key" -H "Content-Type: application/json")

  ###########################################
  ## Set the record identifier from result
  ###########################################
  record_identifier=$(echo "$record" | grep -Po '(?<="id":")[^"]*' | head -1)

  if [ -z "$record_identifier" ]; then
    log_message "Record identifier for $record_name not found."
    return 1
  fi

  ###########################################
  ## Change the IP@Cloudflare using the API
  ###########################################
  update=$(curl -s -X PUT "https://api.cloudflare.com/client/v4/zones/$zone_identifier/dns_records/$record_identifier" -H "X-Auth-Email: $auth_email" -H "X-Auth-Key: $auth_key" -H "Content-Type: application/json" --data "{\"type\":\"A\",\"proxied\":${proxy},\"name\":\"$record_name\",\"content\":\"$ip\"}")

  ###########################################
  ## Report the status
  ###########################################
  case "$update" in
  *""success":false"*)
    log_message "$ip $record_name DDNS failed for $record_identifier ($ip). DUMPING RESULTS:\n$update"
    return 1
    ;;
  *)
    log_message "$ip $record_name DDNS updated."
    return 0
    ;;
  esac
}

###########################################
## Loop through all record names
###########################################
for record_name in "${record_names[@]}"; do
  update_record "$record_name"
done

###########################################
## Save the current IP
###########################################
echo "$ip" > "$ip_file"

Two Steps to Make it Auto-Running

Assign Permission

Make the script executable by setting the appropriate permissions:

sudo chmod +x ~/cloudflare.sh

Add to Your Crontab List

Open the crontab editor to add a new cron job:

sudo crontab -e

Append the following line to the end of the crontab file to schedule the script to run every 10 minutes:

## must be absolute path here
*/10 * * * * /bin/bash /home/yourname/cloudflare.sh