From d2fe417715d2116a33bf6468bb37b272a2be9edb Mon Sep 17 00:00:00 2001
From: missytake <missytake@systemli.org>
Date: Wed, 13 Dec 2023 04:18:25 +0100
Subject: [PATCH] DNS: try other resolvers if the first doesn't have it

---
 cmdeploy/src/cmdeploy/cmdeploy.py | 20 +++++++----
 cmdeploy/src/cmdeploy/dns.py      | 56 +++++++++++++++++--------------
 2 files changed, 45 insertions(+), 31 deletions(-)

diff --git a/cmdeploy/src/cmdeploy/cmdeploy.py b/cmdeploy/src/cmdeploy/cmdeploy.py
index e41a9475..e7aef07a 100644
--- a/cmdeploy/src/cmdeploy/cmdeploy.py
+++ b/cmdeploy/src/cmdeploy/cmdeploy.py
@@ -45,11 +45,11 @@ def init_cmd(args, out):
     to_print = ["Now you should add %dnsentry% at your DNS provider:\n"]
     if not ipaddress:
         entries += 1
-        to_print.append(f"\tA\t{args.chatmail_domain}\t\t<your server's IPv4 address>")
+        to_print.append(f"\tA\t{args.chatmail_domain}.\t\t<your server's IPv4 address>")
     if not mta_ipadress or mta_ipadress != ipaddress:
         entries += 1
         to_print.append(
-            f"\tCNAME\tmta-sts.{args.chatmail_domain}\t{args.chatmail_domain}."
+            f"\tCNAME\tmta-sts.{args.chatmail_domain}.\t{args.chatmail_domain}."
         )
     if entries == 1:
         singular = "this entry"
@@ -126,11 +126,19 @@ def dns_cmd(args, out):
 
     print()
     if not dns.check_ptr_record(ipv4, args.config.mail_domain):
-        print(f"You should add a PTR/reverse DNS entry for {ipv4}, with the value: {args.config.mail_domain}.")
-        print("You can do so at your hosting provider (maybe this isn't your DNS provider).\n")
+        print(
+            f"You should add a PTR/reverse DNS entry for {ipv4}, with the value: {args.config.mail_domain}."
+        )
+        print(
+            "You can do so at your hosting provider (maybe this isn't your DNS provider).\n"
+        )
     if not dns.check_ptr_record(ipv6, args.config.mail_domain):
-        print(f"You should add a PTR/reverse DNS entry for {ipv6}, with the value: {args.config.mail_domain}.")
-        print("You can do so at your hosting provider (maybe this isn't your DNS provider).\n")
+        print(
+            f"You should add a PTR/reverse DNS entry for {ipv6}, with the value: {args.config.mail_domain}."
+        )
+        print(
+            "You can do so at your hosting provider (maybe this isn't your DNS provider).\n"
+        )
 
     to_print = []
     with open(template, "r") as f:
diff --git a/cmdeploy/src/cmdeploy/dns.py b/cmdeploy/src/cmdeploy/dns.py
index e01ded67..d470cdeb 100644
--- a/cmdeploy/src/cmdeploy/dns.py
+++ b/cmdeploy/src/cmdeploy/dns.py
@@ -1,7 +1,11 @@
 import requests
 from ipaddress import ip_address
 
-url = "https://dns.nextdns.io/dns-query"
+resolvers = [
+    "https://dns.nextdns.io/dns-query",
+    "https://dns.google/resolve",
+    "https://cloudflare-dns.com/dns-query",
+]
 dns_types = {
     "A": 1,
     "AAAA": 28,
@@ -20,36 +24,38 @@ class DNS:
 
     def get(self, typ: str, domain: str) -> str:
         """Get a DNS entry"""
-        r = self.session.get(
-            url,
-            params={"name": domain, "type": typ},
-            headers={"accept": "application/dns-json"},
-        )
+        for url in resolvers:
+            r = self.session.get(
+                url,
+                params={"name": domain, "type": typ},
+                headers={"accept": "application/dns-json"},
+            )
 
-        j = r.json()
-        if "Answer" in j:
-            for answer in j["Answer"]:
-                if answer["type"] == dns_types[typ]:
-                    return answer["data"]
+            j = r.json()
+            if "Answer" in j:
+                for answer in j["Answer"]:
+                    if answer["type"] == dns_types[typ]:
+                        return answer["data"]
         return ""
 
     def resolve_mx(self, domain: str) -> (str, str):
         """Resolve an MX entry"""
-        r = self.session.get(
-            url,
-            params={"name": domain, "type": "MX"},
-            headers={"accept": "application/dns-json"},
-        )
+        for url in resolvers:
+            r = self.session.get(
+                url,
+                params={"name": domain, "type": "MX"},
+                headers={"accept": "application/dns-json"},
+            )
 
-        j = r.json()
-        if "Answer" in j:
-            result = (0, None)
-            for answer in j["Answer"]:
-                if answer["type"] == dns_types["MX"]:
-                    prio, server_name = answer["data"].split()
-                    if int(prio) > result[0]:
-                        result = (int(prio), server_name)
-            return result
+            j = r.json()
+            if "Answer" in j:
+                result = (0, None)
+                for answer in j["Answer"]:
+                    if answer["type"] == dns_types["MX"]:
+                        prio, server_name = answer["data"].split()
+                        if int(prio) > result[0]:
+                            result = (int(prio), server_name)
+                return result
         return None, None
 
     def resolve(self, domain: str) -> str: