watcher: a lookup cut short by shutdown is not logged as an error (closes #229)

Stopping dnswatcher during a DNS check logged every lookup the stop cut short as an error, "context canceled". The four places in the watcher that log a failed lookup, checkDomain, checkHostname, resolveNameserverAddresses and resolveCNAMEAddresses, now do it through logFailedLookup, which logs nothing when the watcher's context was cancelled. It asks the context, not the lookup's error: the resolver reports a cancelled lookup with its own error, which does not wrap context.Canceled. A context whose deadline passed is not cancelled, so a lookup that ran out of time is still logged. The tests run each of these lookups on a cancelled context and on one whose deadline passed; neither sends a query. Model: opus-5-5
2026-10-02 08:56:52 +02:00
parent f99de191c0
commit b047c3c64c
4 changed files with 104 additions and 4 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 DNS lookup that shutdown cuts short logs no error; one that
+  fails otherwise, or runs out of time, still does (closes #229).
 - 2026-10-02: Record Change and Inconsistency notifications list only the record
  types that differ, each with its values as plain text (closes #219).
 - 2026-10-02: the startup notification no longer says every notification