Add a script for TS DNS

scripts/ts-rebuild-dns

@@ -0,0 +1,115 @@
+#! /usr/bin/env python3
+import argparse
+import sys
+import logging
+import subprocess
+import requests
+from oauthlib.oauth2 import BackendApplicationClient
+from requests_oauthlib import OAuth2Session  # pip install requests-oauthlib
+
+logger = logging.getLogger(__name__)
+
+
+def main() -> int:
+    # Handle program arguments
+    ap = argparse.ArgumentParser(
+        prog="ts-rebuild-dns", description="Writes Tailscale hostnames into DNS"
+    )
+    ap.add_argument(
+        "-v", "--verbose", help="Enable verbose logging", action="store_true"
+    )
+    args = ap.parse_args()
+
+    # Configure logging
+    logging.basicConfig(
+        level=logging.DEBUG if args.verbose else logging.INFO,
+        format="%(levelname)s:	%(message)s",
+    )
+
+    # Read relevant secrets
+    tailscale_oauth_client_id = "k2riEfMYLA11CNTRL"
+    tailscale_oauth_client_secret = (
+        subprocess.check_output(
+            ["op", "read", "op://Personal/ysffqv6vsom2hixv37iiotmtbm/credential"]
+        )
+        .decode()
+        .strip()
+    )
+    cloudflare_api_token = (
+        subprocess.check_output(
+            ["op", "read", "op://Personal/7hrhdwzhpasoqegmlv7wprjzaa/credential"]
+        )
+        .decode()
+        .strip()
+    )
+
+    # Authenticate with Tailscale
+    tailscale_client = BackendApplicationClient(client_id=tailscale_oauth_client_id)
+    tailscale_oauth = OAuth2Session(client=tailscale_client)
+    tailscale_token = tailscale_oauth.fetch_token(
+        token_url="https://api.tailscale.com/api/v2/oauth/token",
+        client_id=tailscale_oauth_client_id,
+        client_secret=tailscale_oauth_client_secret,
+    )
+
+    # Get the list of Tailscale devices
+    tailscale_devices = tailscale_oauth.get(
+        "https://api.tailscale.com/api/v2/tailnet/-/devices"
+    ).json()
+
+    # Build sets of DNS records
+    records = []
+    for device in tailscale_devices["devices"]:
+        name = device["name"].split(".")[0]
+        for address in device["addresses"]:
+            if ":" in address:
+                records.append(("AAAA", f"{name}.mesh.ewpratten.net", address))
+            else:
+                records.append(("A", f"{name}.mesh.ewpratten.net", address))
+
+    # Fetch all existing records from Cloudflare
+    cloudflare_records = requests.get(
+        f"https://api.cloudflare.com/client/v4/zones/3d8ef70ae28b8a5d97a200550dc95ed1/dns_records",
+        headers={"Authorization": f"Bearer {cloudflare_api_token}"},
+    ).json()["result"]
+
+    # Only look at records under the mesh subdomain
+    cloudflare_records = [
+        record
+        for record in cloudflare_records
+        if record["name"].endswith(".mesh.ewpratten.net")
+    ]
+    
+    # Delete all records that are stale
+    for record in cloudflare_records:
+        if (record["type"], record["name"], record["content"]) not in records:
+            logger.info(f"Deleting {record['type']} record {record['name']} -> {record['content']}")
+            requests.delete(
+                f"https://api.cloudflare.com/client/v4/zones/3d8ef70ae28b8a5d97a200550dc95ed1/dns_records/{record['id']}",
+                headers={"Authorization": f"Bearer {cloudflare_api_token}"},
+            )
+            
+    # Add all records that are missing
+    for record in records:
+        if not any(
+            r["type"] == record[0] and r["name"] == record[1] and r["content"] == record[2]
+            for r in cloudflare_records
+        ):
+            logger.info(f"Adding {record[0]} record {record[1]} -> {record[2]}")
+            requests.post(
+                f"https://api.cloudflare.com/client/v4/zones/3d8ef70ae28b8a5d97a200550dc95ed1/dns_records",
+                headers={"Authorization": f"Bearer {cloudflare_api_token}"},
+                json={
+                    "type": record[0],
+                    "name": record[1],
+                    "content": record[2],
+                    "ttl": 120,
+                    "proxied": False,
+                },
+            )
+
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())