resolver, watcher: a record type whose query fails keeps its previous records (closes #231)

The resolver lists in FailedTypes each record type whose query to a nameserver got no usable reply (no reply, a code other than NOERROR or NXDOMAIN, a referral, or a truncated reply whose TCP retry failed) and logs it unless shutdown cut it short. A nameserver that answered no type has failed. The watcher saves such a type in failedTypes with the previous check's records, leaves it out of the comparison with other nameservers on that check, and compares it with the next answer. When the previous check did not know its records either, it is also in unknownTypes and not compared until it answers. A nameserver whose A, AAAA or CNAME query failed is no answer when following a CNAME or resolving addresses. Model: opus-5-5
2026-10-02 10:51:23 +02:00
parent 9b524e9d63
commit 9b9e26d6b2
16 changed files with 936 additions and 65 deletions
@@ -19,6 +19,8 @@ trial run of the finished image: https://git.eeqj.de/sneak/dnswatcher/issues/149

 # Completed Steps

+- 2026-10-02: a record type whose query to a nameserver fails keeps its previous
+  records and alerts nothing; the other types are still saved (closes #231).
 - 2026-10-02: a Port Change notification lists the port's domains on a
  `Domains:` line and its hostnames on a `Hostnames:` line (closes #248).
 - 2026-10-02: the dashboard's Ports table and `/api/v1/status` port entries list