Simplified the script by adding Runitor

dnsupdater/Dockerfile

@@ -1,8 +1,20 @@
+FROM alpine:latest AS builder
+
+ARG TARGETPLATFORM
+
+RUN DOWNLOAD_ARCH=$(echo ${TARGETPLATFORM} | cut -d"/" -f 2) \
+	&& apk add --no-cache curl \
+	&& DOWNLOAD_URL=$(curl -s https://api.github.com/repos/bdd/runitor/releases/latest | grep "browser_download_url" | grep "linux-"${DOWNLOAD_ARCH} | cut -d\" -f4) \
+	&& curl --retry 3 -L -s -o runitor ${DOWNLOAD_URL} \
+	&& chmod +x runitor
+
 FROM alpine:latest
 
-ADD dnsupdater.sh /usr/bin/dnsupdater.sh
+COPY --from=builder runitor /usr/bin/
+
+ADD dnsupdater.sh docker-command.sh /usr/bin/
 
 RUN apk add --no-cache bash curl jq bind-tools \
 	&& chmod +x /usr/bin/dnsupdater.sh
 
-CMD /usr/bin/dnsupdater.sh
+CMD ["/usr/bin/docker-command.sh"]

dnsupdater/dnsupdater.sh

@@ -1,59 +1,58 @@
 #!/bin/bash
 
-while true ; do
-  # Get my current IP
-  my_ip=$(curl -s https://api.ipify.org)
+# Get my IP
+my_ip=$(curl -s https://api.ipify.org)
+if [[ ! ("$my_ip" =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$) ]] ; then
+  echo "Got incorrect IP: $my_ip"
+  exit 1
+fi
 
-  # Get my currently registered IP
-  current_ip=
-  if [[ "$GANDI_API_KEY" != "" ]] ; then
+# Get my registered IP
+current_ip=
+if [[ "$GANDI_API_KEY" != "" ]] ; then
   current_ip=$(curl -s -H"X-Api-Key: $GANDI_API_KEY" https://dns.api.gandi.net/api/v5/domains/$DNS_DOMAIN/records | jq -r '.[] | select(.rrset_name == "'$DNS_HOST'") | select(.rrset_type == "A") | .rrset_values[0]')
-  elif [[ "$OVH_USERNAME" != "" ]] ; then
+elif [[ "$OVH_USERNAME" != "" ]] ; then
   master_server=$(dig +short -t NS $DNS_DOMAIN | head -n 1)
   current_ip=$(dig +short @$master_server $DNS_HOST.$DNS_DOMAIN)
-  fi
+else
+  echo "No DNS provider configured"
+  exit 2
+fi
+if [[ ! ("$current_ip" =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$) ]] ; then
+  echo "Incorrect registered IP: $current_ip"
+  exit 3
+fi
 
-  # Check if both IP addresses are correct
-  if [[ "$my_ip" =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ && "$current_ip" =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ ]] ; then
-    # If they do not match, change it (and keep the TTL and TYPE)
-    if [[ "$my_ip" != "$current_ip" ]]; then
-      result=1
-      echo "Updating $DNS_HOST.$DNS_DOMAIN record with IP $my_ip"
-      if [[ "$GANDI_API_KEY" != "" ]] ; then
+# If they match, do nothing
+if [[ "$my_ip" == "$current_ip" ]]; then
+  echo "$DNS_HOST.$DNS_DOMAIN record already up-to-date with IP $my_ip"
+  exit 0
+fi
+
+# Update the DNS record
+echo "Updating $DNS_HOST.$DNS_DOMAIN record with IP $my_ip"
+if [[ "$GANDI_API_KEY" != "" ]] ; then
   current_record=$(curl -s -H"X-Api-Key: $GANDI_API_KEY" https://dns.api.gandi.net/api/v5/domains/$DNS_DOMAIN/records | jq -c '.[] | select(.rrset_name == "'$DNS_HOST'") | select(.rrset_type == "A")')
   current_ttl=$(echo $current_record | jq -r '.rrset_ttl')
   curl -s -X PUT -H "Content-Type: application/json" -H "X-Api-Key: $GANDI_API_KEY" -d '{"rrset_ttl": '$current_ttl', "rrset_values":["'$my_ip'"]}' https://dns.api.gandi.net/api/v5/domains/$DNS_DOMAIN/records/$DNS_HOST/A
-	result=$?
-      elif [[ "$OVH_USERNAME" != "" ]] ; then
+  if [[ $? != 0 ]] ; then
+    echo "Unable to update GANDI record"
+    exit 4
+  fi
+elif [[ "$OVH_USERNAME" != "" ]] ; then
   curl -s --user "$OVH_USERNAME:$OVH_PASSWORD" "http://www.ovh.com/nic/update?system=dyndns&hostname=$DNS_HOST.$DNS_DOMAIN&myip=$my_ip"
-	result=$?
+  if [[ $? != 0 ]] ; then
+    echo "Unable to update OVH record"
+    exit 5
   fi
+fi
 
-      # If the update was OK
-      if [[ $result == 0 ]] ; then
-        # Send a notification to Slack
-        if [[ "$SLACK_URL" != "" ]] ; then
+# Send a notification to Slack
+if [[ "$SLACK_URL" != "" ]] ; then
   curl -o /dev/null -s -m 10 --retry 5 -X POST -d "payload={\"username\": \"gandi\", \"icon_emoji\": \":dart:\", \"text\": \"New IP $my_ip for host $DNS_HOST.$DNS_DOMAIN\"}" $SLACK_URL
-        fi
+fi
 
-        # Send a notification to Gotify
-        if [[ "$GOTIFY_URL" != "" ]] ; then
+# Send a notification to Gotify
+if [[ "$GOTIFY_URL" != "" ]] ; then
    curl -o /dev/null -s -m 10 --retry 5 -X POST -H "accept: application/json" -H "Content-Type: application/json" -d "{\"priority\": 5, \"title\": \"New IP for host $DNS_HOST.$DNS_DOMAIN\", \"message\": \"New IP $my_ip for host $DNS_HOST.$DNS_DOMAIN, the old IP was $current_ip\"}" $GOTIFY_URL
-        fi
-
-        # Send a notification to Healthchecks
-        if [[ "$HEALTHCHECKS_URL" != "" ]] ; then
-          curl -o /dev/null -s -m 10 --retry 5 $HEALTHCHECKS_URL
-        fi
-      fi
-    else
-      # Send a notification to Healthchecks
-      if [[ "$HEALTHCHECKS_URL" != "" ]] ; then
-        curl -o /dev/null -s -m 10 --retry 5 $HEALTHCHECKS_URL
-      fi
-    fi
-  fi
-
-  # Wait 5 minutes
-  sleep 300
-done
+fi