[v16] migrate teleport wait no-resolve to slog and add more details…

… in logs (#49569)

* migrate to slog. add more details in logs

* make linter happy

* remove unsupported error unwrap

tool/teleport/common/wait.go

@@ -29,7 +29,6 @@ import (
 	"time"
 
 	"github.com/gravitational/trace"
-	log "github.com/sirupsen/logrus"
 
 	"github.com/gravitational/teleport/api/utils/retryutils"
 	"github.com/gravitational/teleport/lib/utils"
@@ -92,6 +91,8 @@ func waitNoResolve(ctx context.Context, domain string, period, timeout time.Dura
 	if timeout == 0 {
 		return trace.BadParameter("no timeout provided")
 	}
+	log := slog.With("domain", domain)
+	log.InfoContext(ctx, "waiting until the domain stops resolving to ensure that every auth server running the previous major version has been updated/terminated")
 
 	var err error
 	ctx, cancel := context.WithTimeout(ctx, timeout)
@@ -124,44 +125,58 @@ func waitNoResolve(ctx context.Context, domain string, period, timeout time.Dura
 			return trace.Wrap(err)
 
 		case <-periodic.Next():
-			exit, err = checkDomainNoResolve(domain)
+			exit, err = checkDomainNoResolve(ctx, domain, log)
 			if err != nil {
 				return trace.Wrap(err)
 			}
 		}
 	}
 
-	log.Info("no endpoints found, exiting with success code")
+	log.InfoContext(ctx, "no endpoints found, exiting with success code")
 	return nil
 }
 
-func checkDomainNoResolve(domainName string) (exit bool, err error) {
-	endpoints, err := countEndpoints(domainName)
+func checkDomainNoResolve(ctx context.Context, domainName string, log *slog.Logger) (exit bool, err error) {
+	endpoints, err := resolveEndpoints(domainName)
 	if err != nil {
 		var dnsErr *net.DNSError
 		if !errors.As(trace.Unwrap(err), &dnsErr) {
-			log.Errorf("unexpected error when resolving domain %s : %s", domainName, err)
+			log.ErrorContext(ctx, "unexpected error when resolving domain", "error", err)
 			return false, trace.Wrap(err)
 		}
-		if dnsErr.Temporary() {
-			log.Warnf("temporary error when resolving domain %s : %s", domainName, err)
-			return false, nil
-		}
+
 		if dnsErr.IsNotFound {
-			log.Infof("domain %s not found", domainName)
+			log.InfoContext(ctx, "domain not found")
 			return true, nil
 		}
-		log.Errorf("error when resolving domain %s : %s", domainName, err)
+
+		// Creating a new logger because the linter doesn't want both key/value and slog.Attr in the same log write.
+		log := log.With(slog.Group("dns_error",
+			"name", dnsErr.Name,
+			"server", dnsErr.Server,
+			"is_timeout", dnsErr.IsTimeout,
+			"is_temporary", dnsErr.IsTemporary,
+			"is_not_found", dnsErr.IsNotFound,
+		))
+		if dnsErr.Temporary() {
+			log.WarnContext(ctx, "temporary error when resolving domain", "error", err)
+			return false, nil
+		}
+		log.ErrorContext(ctx, "error when resolving domain", "error", err)
 		return false, nil
 	}
-	log.Infof("%d endpoints found when resolving domain %s", endpoints, domainName)
-	return endpoints == 0, nil
+	if len(endpoints) == 0 {
+		log.InfoContext(ctx, "domain found and resolution returned no endpoints")
+		return true, nil
+	}
+	log.InfoContext(ctx, "endpoints found when resolving domain", "endpoints", endpoints)
+	return false, nil
 }
 
-func countEndpoints(serviceName string) (int, error) {
+func resolveEndpoints(serviceName string) ([]net.IP, error) {
 	ips, err := net.LookupIP(serviceName)
 	if err != nil {
-		return 0, trace.Wrap(err)
+		return nil, trace.Wrap(err)
 	}
-	return len(ips), nil
+	return ips, nil
 }