libnetwork: resolve: use structured logs for DNS error

I noticed that this log didn't use structured logs;

    [resolver] failed to query DNS server: 10.115.11.146:53, query: ;google.com.\tIN\t A" error="read udp 172.19.0.2:46361->10.115.11.146:53: i/o timeout
    [resolver] failed to query DNS server: 10.44.139.225:53, query: ;google.com.\tIN\t A" error="read udp 172.19.0.2:53991->10.44.139.225:53: i/o timeout

But other logs did;

    DEBU[2024-02-20T15:48:51.026704088Z] [resolver] forwarding query                   client-addr="udp:172.19.0.2:39661" dns-server="udp:192.168.65.7:53" question=";google.com.\tIN\t A"
    DEBU[2024-02-20T15:48:51.028331088Z] [resolver] forwarding query                   client-addr="udp:172.19.0.2:35163" dns-server="udp:192.168.65.7:53" question=";google.com.\tIN\t AAAA"
    DEBU[2024-02-20T15:48:51.057329755Z] [resolver] received AAAA record "2a00:1450:400e:801::200e" for "google.com." from udp:192.168.65.7
    DEBU[2024-02-20T15:48:51.057666880Z] [resolver] received A record "142.251.36.14" for "google.com." from udp:192.168.65.7

As we're already constructing a logger with these fields, we may as well use it.

Signed-off-by: Sebastiaan van Stijn <[email protected]>

libnetwork/resolver.go

@@ -576,7 +576,7 @@ func (r *Resolver) exchange(ctx context.Context, proto string, extDNS extDNSEntr
 		UDPSize: dns.MaxMsgSize,
 	}).ExchangeWithConn(query, &dns.Conn{Conn: extConn})
 	if err != nil {
-		r.log(ctx).WithError(err).Errorf("[resolver] failed to query DNS server: %s, query: %s", extConn.RemoteAddr().String(), query.Question[0].String())
+		logger.WithError(err).Error("[resolver] failed to query external DNS server")
 		span.RecordError(err)
 		span.SetStatus(codes.Error, "ExchangeWithConn failed")
 		return nil