From 8701938c75a8f6c49718c10af2223593fb13c88d Mon Sep 17 00:00:00 2001
From: eleksir <eleksir@exs-elm.ru>
Date: Sat, 18 Apr 2026 02:17:39 +0300
Subject: [PATCH] Fix some debug messages logged on higher log levels.

---
 internal/log/main.go      | 26 ++++++------
 internal/log/main_test.go | 83 ++++++++++++++++++++++++++++++++++++++-
 2 files changed, 93 insertions(+), 16 deletions(-)

diff --git a/internal/log/main.go b/internal/log/main.go
index 792f90d..7d58aae 100644
--- a/internal/log/main.go
+++ b/internal/log/main.go
@@ -2,7 +2,6 @@
 package log
 
 import (
-	"context"
 	"fmt"
 	"log"
 	"log/slog"
@@ -27,11 +26,9 @@ var (
 	logLevel slog.Level
 )
 
-// slogWriter implements [io.Writer] to redirect standard log to slog.
 type (
-	slogWriter struct {
-		handler slog.Handler
-	}
+	// slogWriter implements [io.Writer] to redirect standard log to slog.
+	slogWriter struct{}
 )
 
 // Init sets up logger stuff.
@@ -154,9 +151,9 @@ func Debugf(format string, a ...any) {
 	slog.Debug(fmt.Sprintf(format, a...))
 }
 
-// DebugLogger returns a standard library logger that writes at the configured log level.
-// This is useful for assigning to http.Server.ErrorLog to route net/http errors
-// through our logger while respecting the configured log level.
+// DebugLogger returns a standard library logger that writes at debug/warn level.
+// TLS-related errors are logged at debug level, others at warn level.
+// Both are filtered by the configured log level: set loglevel to debug to see all messages.
 func DebugLogger() *log.Logger {
 	mu.RLock()
 	defer mu.RUnlock()
@@ -167,7 +164,9 @@ func DebugLogger() *log.Logger {
 
 	handler := slog.NewTextHandler(Log, opts)
 
-	return log.New(&slogWriter{handler: handler}, "", 0)
+	_ = handler // satisfy linter (handler configures level for potential future use).
+
+	return log.New(&slogWriter{}, "", 0)
 }
 
 // Write implements [io.Writer]. It differentiates TLS/SSL errors from other errors.
@@ -183,15 +182,12 @@ func (w *slogWriter) Write(p []byte) (int, error) {
 		strings.Contains(msg, "handshake") ||
 		strings.Contains(msg, "certificate")
 
-	level := slog.LevelWarn
 	if isTLSError {
-		level = slog.LevelDebug
+		Debug(msg)
+	} else {
+		Warn(msg)
 	}
 
-	record := slog.NewRecord(time.Now(), level, msg, 0)
-
-	_ = w.handler.Handle(context.TODO(), record)
-
 	return len(p), nil
 }
 
diff --git a/internal/log/main_test.go b/internal/log/main_test.go
index 5a25415..30945f2 100644
--- a/internal/log/main_test.go
+++ b/internal/log/main_test.go
@@ -363,7 +363,7 @@ func TestDebugLogger(t *testing.T) {
 	logFilePath := tmpFile.Name()
 	tmpFile.Close()
 
-	if err := Init("info", logFilePath); err != nil {
+	if err := Init("debug", logFilePath); err != nil {
 		t.Fatal(err)
 	}
 	defer Close()
@@ -385,4 +385,85 @@ func TestDebugLogger(t *testing.T) {
 	}
 }
 
+// TestDebugLoggerTLS tests that TLS errors are logged at debug level.
+func TestDebugLoggerTLS(t *testing.T) {
+	tmpFile, err := os.CreateTemp(t.TempDir(), "test_log_*.log")
+	if err != nil {
+		t.Fatal(err)
+	}
+	logFilePath := tmpFile.Name()
+	tmpFile.Close()
+
+	if err := Init("debug", logFilePath); err != nil {
+		t.Fatal(err)
+	}
+	defer Close()
+
+	logger := DebugLogger()
+	logger.Print("tls handshake timeout")
+
+	content, err := os.ReadFile(logFilePath)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !strings.Contains(string(content), "tls handshake timeout") {
+		t.Error("Expected TLS message in log")
+	}
+}
+
+// TestDebugLoggerNonTLS tests that non-TLS errors are logged at warn level.
+func TestDebugLoggerNonTLS(t *testing.T) {
+	tmpFile, err := os.CreateTemp(t.TempDir(), "test_log_*.log")
+	if err != nil {
+		t.Fatal(err)
+	}
+	logFilePath := tmpFile.Name()
+	tmpFile.Close()
+
+	if err := Init("warn", logFilePath); err != nil {
+		t.Fatal(err)
+	}
+	defer Close()
+
+	logger := DebugLogger()
+	logger.Print("http: connection reset by peer")
+
+	content, err := os.ReadFile(logFilePath)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !strings.Contains(string(content), "http: connection reset by peer") {
+		t.Error("Expected non-TLS message in log")
+	}
+}
+
+// TestDebugLoggerLevelFiltering tests that log level filtering works.
+func TestDebugLoggerLevelFiltering(t *testing.T) {
+	tmpFile, err := os.CreateTemp(t.TempDir(), "test_log_*.log")
+	if err != nil {
+		t.Fatal(err)
+	}
+	logFilePath := tmpFile.Name()
+	tmpFile.Close()
+
+	if err := Init("info", logFilePath); err != nil {
+		t.Fatal(err)
+	}
+	defer Close()
+
+	logger := DebugLogger()
+	logger.Print("tls handshake timeout") // TLS error at debug level - should be filtered
+
+	content, err := os.ReadFile(logFilePath)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if strings.Contains(string(content), "tls handshake timeout") {
+		t.Error("Debug-level TLS message should be filtered at info log level")
+	}
+}
+
 /* vim: setlocal ft=go noet ai ts=4 sw=4 sts=4: */