Add command line document

cloudflare_ddns/__main__.py

@@ -1,28 +1,61 @@
 import logging
+from os import environ
 from typing import Tuple
 
 import click
 from cloudflare_ddns.app import ApplicationJob
-from cloudflare_ddns.constants import DEFAULT_DELAY
+from cloudflare_ddns.constants import BASE_ENV_VAR, DEFAULT_DELAY, DOMAINS_ENV_VAR
 
 log = logging.getLogger("ddns")
 
 
 @click.command()
-@click.option('--delay', '-d', default=DEFAULT_DELAY, show_default=True)
-@click.option('--token', '-k', prompt="Enter your Cloudflare Token", hide_input=True, show_envvar=True)
-@click.option('-v', '--verbose', is_flag=True, default=False)
-@click.argument("domain", nargs=-1)
-def start(delay: str, token: str, verbose: int, domain: Tuple[str]) -> None:
-    """Main application entrypoint."""
+@click.option(
+    '--delay', '-d',
+    default=DEFAULT_DELAY,
+    show_default=True,
+    show_envvar=True,
+    help="Time to wait between each update."
+)
+@click.option(
+    '--token', '-k',
+    prompt="Enter your Cloudflare Token",
+    hide_input=True,
+    show_envvar=True,
+    help="Your Cloudflare Bearer token."
+)
+@click.option('-v', '--verbose', is_flag=True, default=False, help="Show debug logging.")
+@click.argument("domains", nargs=-1)
+def start(delay: str, token: str, verbose: int, domains: Tuple[str]) -> None:
+    """
+    Update Cloudflare DNS RECORDS to your current IP every <delay> (default: 5 minutes).
+
+    The domains can be passed either as command line options, or as a space separated CF_DDNS_DOMAINS environment
+    variable.
+    Each domain can be preceded by the record type, either A or AAAA followed by a colon.
+
+    \b
+    The duration supports the following symbols for each unit of time:
+        - days: `d`, `D`, `day`, `days`
+        - hours: `H`, `h`, `hour`, `hours`
+        - minutes: `M`, `m`, `minute`, `minutes`, `min`
+        - seconds: `S`, `s`, `second`, `seconds`, `sec`
+    The units need to be provided in descending order of magnitude.
+    """
+    # Configure logging.
     logging.basicConfig(
         format="%(asctime)s - %(name)s - %(levelname)s - %(message)s",
         level=logging.DEBUG if verbose else logging.INFO
     )
 
-    ApplicationJob(delay, token, domain).launch()
+    # Get domains from the environment variable.
+    if domain_var := environ.get(DOMAINS_ENV_VAR, None):
+        domains = list(domains)
+        domains.extend(domain_var.split(" "))
+
+    ApplicationJob(delay, token, domains).launch()
 
 
 # Main entrypoint
 if __name__ == "__main__":
-    start(auto_envvar_prefix="CF_DDNS")
+    start(auto_envvar_prefix=BASE_ENV_VAR)

cloudflare_ddns/app.py

@@ -1,7 +1,7 @@
 import logging
 import threading
 from dataclasses import dataclass
-from typing import List, Tuple
+from typing import List
 
 import requests
 from cloudflare_ddns.constants import ACCEPTED_RECORDS, LIST_DNS, LIST_ZONES, PATCH_DNS, VERIFY_TOKEN
@@ -32,7 +32,7 @@ class Domain:
 class ApplicationJob(threading.Thread):
     """Main application class."""
 
-    def __init__(self, raw_delay: str, token: str, raw_domains: Tuple[str]):
+    def __init__(self, raw_delay: str, token: str, raw_domains: List[str]):
         super().__init__()
 
         self.stop_signal = threading.Event()

cloudflare_ddns/constants.py

@@ -1,6 +1,10 @@
 # App defaults
 DEFAULT_DELAY = "5 minutes"
 
+# App constants
+BASE_ENV_VAR = "CF_DDNS"
+DOMAINS_ENV_VAR = BASE_ENV_VAR + "_DOMAINS"
+
 # Endpoints
 BASE_ENDPOINT = "https://api.cloudflare.com/client/v4/"