Refactored logic. Fixed for #2.

parthpower · Jan 1, 2019 · c915d33 · c915d33
1 parent 4af8757
commit c915d33
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Showing 2 changed files with 67 additions and 53 deletions.
diff --git a/README.md b/README.md
@@ -59,6 +59,8 @@ I have no idea but it should work.
 
 ## Notes
 
+- To save number of API calls this script updates the `A` record only when the host IP changes. It does not periodically check if the record is modified by other means. You can use `--always-update-dns` to update the record entry at the interval.
+
 - What is DNS record? https://www.cloudflare.com/learning/dns/dns-records/ (Psst: We are just messing with `A` record here)
 
 - Works on CloudFlare API `v4`

diff --git a/cf_ddns.sh b/cf_ddns.sh
@@ -7,6 +7,7 @@
 # Load Default Config
 interval=10
 save=false
+always_update_dns=false
 . ./config.ini
 while (( "$#" )); do
 	case "$1" in
@@ -34,15 +35,21 @@ while (( "$#" )); do
 			save=true
 			shift
 			;;
+		--always-update-dns)
+			always_update_dns=true
+			shift
+			;;
 		-h|--help)
 			printf "Usage: ./cf_ddns.sh \t[-z|--zone <zone id> 
 			-e|--email <email> 
 			-k|--key <API key>]
 			[-c|--config <config file to load/store>] 
 			[-s|--save]
+			[--always-update-dns]
 			[-i|--interval <update interval in seconds>]
 			[sub.primary.com]
-
+	
+	Use --alway-update-dns will match DNS record with the machine IP at every interval. Not recommended for free tier DNS.
 Example:
 To host current ip at test.example.com
 ./cf_ddns.sh --key <api key> --zone <zone id> --email <your email> --interval 60 --config config.ini --save test.example.com
@@ -64,12 +71,12 @@ done
 
 if [[ $config_file ]]; then
 	if [[ $save ]]; then
-		echo "Saving config..."
-		echo "zone=$zone;" 	>  $config_file
-		echo "key=$key;" 	>> $config_file
-		echo "email=$email;" >> $config_file
-		echo "name=$name;" >> $config_file
-        echo "interval=$interval;" >> $config_file
+		echo "Saving config...";
+		echo "zone=$zone;" 	>  $config_file;
+		echo "key=$key;" 	>> $config_file;
+		echo "email=$email;" >> $config_file;
+		echo "name=$name;" >> $config_file;
+        echo "interval=$interval;" >> $config_file;
 	else
 		. $config_file
 	fi
@@ -79,76 +86,81 @@ fi
 printf "[config] Zone:\t$zone
 [config] Key:\t************
 [config] Email:\t$email
-[config] Name:\t$name\n"
+[config] Name:\t$name\n";
 
 # Main Code
 ###############
 endpoint="https://api.cloudflare.com/client/v4/zones/$zone/dns_records";
 headers="-H Content-type:application/json -H X-Auth-Key:$key -H X-Auth-Email:$email";
-
-# Get Current IP Address and try to find records similar to it
-echo "[$(date)] INFO: Getting IP"
-ip=$(curl -s http://api.ipify.org||echo 'null');
-last_ip=$ip;
-
-echo "[$(date)] INFO: Current IP:$last_ip"
-echo "[$(date)] INFO: Fetchin Record"
-
-content=$(curl -s -X GET $headers $endpoint\?content=$ip\&name=$name||echo 'null');
-id=$(echo $content|jq -r '.result[0].id')	# it will be 'null' if not found. Checked in main loop.
-sucess=$(echo $content|jq -r '.result[0].sucess')
-
-# Make sure internet is working to start up
-while [[ $last_ip = 'null' || sucess = 'false' ]]; do
-	last_ip=$(curl -s http://api.ipify.org||echo 'null')
-	content=$(curl -s -X GET $headers $endpoint\?content=$ip\&name=$name||echo 'null');
-	id=$(echo $content|jq -r '.result[0].id');
-	name=$(echo $content|jq -r '.result[0].name');
-	sucess=$(echo $content|jq -r '.result[0].sucess');
-	# We are offline
-	echo "[$(date)] WARNING: Offline. Waiting for $interval s."
-	sleep $interval
-	continue
-done
-
 a_name=$(echo $name|cut -d'.' -f1)
+id="null";
+last_ip="null";
 
 while [[ true ]]; do
 	# Update IP
 	current_ip=$(curl -s http://api.ipify.org||echo 'null')
-	echo "[$(date)] INFO: Current IP:$ip";
 
 	# Check if offline
 	if [[ $current_ip = 'null' ]]; then
-
-		echo "[$(date)] WARNING: You are offline"
+		echo "[$(date)] WARNING: Failed to get your IP.";
 		sleep $interval
 		continue
+	else
+		echo "[$(date)] INFO: Current IP:$current_ip";
 	fi
 
-	# Check for IP Updates or if it requires creating new record.
-	if [[ $current_ip = $last_ip && $id != 'null' ]]; then
-
-		echo "[$(date)] INFO: No updates"
-		sleep $interval
-		continue
+	if [[ $always_update_dns = 'false' ]] ; then
+		# Skip to start if there is no updates in IP
+		if [[ $current_ip = $last_ip ]]; then
+			echo "[$(date)] INFO: Host IP Unchanged. Not checking DNS Records.";
+			sleep $interval;
+			continue;
+		else
+			last_ip=$current_ip; 
+		fi
 	fi
-
-	# Code gets here only if IP is updated or to create new record
-	last_ip=$current_ip;
-	ip=$current_ip;
+
+	# Check if DNS Record Exist
+	echo "[$(date)] INFO: Checking for existing DNS Record.";
+	content=$(curl -s -X GET $headers $endpoint\?\&name=$name||echo 'null');
+	id=$(echo $content|jq -r '.result[0].id');
+	ip_on_record=$(echo $content|jq -r '.result[0].content');
+	echo "[$(date)] INFO: DNS Record ID:$id";
+	echo "[$(date)] INFO: IP on DNS Record $ip_on_record";
 
 	if [[ $id = 'null' ]] ; then
 		# Create Record
 		echo "[$(date)] INFO: Creating New Record"
-		content=$(curl -s -X POST $headers $endpoint/$id -d "{\"type\":\"A\",\"name\":\"$a_name\",\"content\":\"$ip\",\"proxied\":false}");
+		content=$(curl -s -X POST $headers $endpoint -d "{\"type\":\"A\",\"name\":\"$a_name\",\"content\":\"$current_ip\",\"proxied\":false}");
+		id=$(echo $content|jq -r '.result.id');
+
+		echo "[$(date)] INFO: $content";
+		echo "[$(date)] INFO: Record ID:$id";
+
+		if [[ $(echo $content | jq -r '.success') != 'true' ]]; then
+			echo "[$(date)] ERROR: Failed with errors $(echo $content | jq -r '.errors')";
+			continue;
+		fi
 	else
-		echo "[$(date)] INFO: Updating Record"
-		content=$(curl -s -X PUT $headers $endpoint -d "{\"type\":\"A\",\"name\":\"$a_name\",\"content\":\"$ip\",\"proxied\":false}");
+		if [[ $ip_on_record != $current_ip ]]; then
+			# Update Existing DNS Record
+			echo "[$(date)] INFO: Updating Existing Record ID: $id";
+			content=$(curl -s -X PUT $headers $endpoint/$id -d "{\"type\":\"A\",\"name\":\"$a_name\",\"content\":\"$current_ip\",\"proxied\":false}");
+			id=$(echo $content|jq -r '.result.id');
+
+			echo "[$(date)] INFO: $content";
+			echo "[$(date)] INFO: Record ID:$id";
+
+			if [[ $(echo $content | jq -r '.success') != 'true' ]]; then
+				echo "[$(date)] ERROR: Failed with errors $(echo $content | jq -r '.errors')";
+				continue;
+			fi
+
+		else
+			echo "[$(date)] INFO: Not updating A record because IP on record is same as host ip.";
+		fi
 	fi
-	id=$(echo $content|jq -r '.result.id');
-	echo "[$(date)] INFO: $content";
-	echo "[$(date)] INFO: Record ID:$id";
+
 	sleep $interval
 done