Fire a single ddns update

Dockerfile

@@ -3,4 +3,5 @@ RUN pip install --no-cache-dir --upgrade pip
 
 WORKDIR /app
 COPY src/ ./
+RUN pip install --no-cache-dir --requirement requirements.txt
 CMD [ "python", "ddns_update.py" ]

src/ddns_update.py

@@ -1,15 +1,56 @@
 #!/usr/bin/python3
 
-from time import sleep
 import logging
+import requests
+from requests.exceptions import RequestException
+import click
+from os import environ
 
 logging.basicConfig(level=logging.DEBUG)
 log = logging.getLogger("ddns updater")
 
+
+def response_successful(response_text):
+    return response_text.startswith("good") or response_text.startswith("nochg")
+
+
+@click.command()
+@click.option(
+    "--host",
+    required=True,
+    default=lambda: environ.get("DDNS_HOST", None),
+    help="The dns name to update",
+)
+@click.option(
+    "--key",
+    required=True,
+    default=lambda: environ.get("DDNS_KEY", None),
+    help="The ddns authorization key",
+)
+@click.option(
+    "--ip",
+    required=True,
+    default=lambda: environ.get("DDNS_IP", None),
+    help="The hosts new ip address in ipv4 or ipv6 format",
+)
+def ddns_update(host, key, ip):
+    url = f"https://dyndns.strato.com/nic/update?hostname={host}&myip={ip}"
+
+    try:
+        response = requests.get(url, auth=(host, key), timeout=3)
+        response.raise_for_status()
+
+        if not response_successful(response.text):
+            raise RequestException("update failed")
+
+    except RequestException as error:
+        log.debug(response.text.strip())
+        log.error(error)
+        return
+
+    log.debug(response.text.strip())
+    log.info("update successful")
+
+
 if __name__ == "__main__":
-    log.info("starting...")
-    sequence = 1
-    while True:
-        log.debug(f"update sequence {sequence}")
-        sequence += 1
-        sleep(5)
+    ddns_update()

src/requirements.txt

@@ -0,0 +1,2 @@
+Click==7.0
+requests==2.23.0