Merge pull request #1442 from afjcjsbx/feat/logger-stdout-formatting

feat(logger): Custom console formatter for JSON and multiline strings

Author: afjcjsbx

pkg/logger/logger.go

@@ -5,6 +5,7 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+	"strconv"
 	"strings"
 	"sync"
 
@@ -45,13 +46,47 @@ func init() {
 		consoleWriter := zerolog.ConsoleWriter{
 			Out:        os.Stdout,
 			TimeFormat: "15:04:05", // TODO: make it configurable???
+
+			// Custom formatter to handle multiline strings and JSON objects
+			FormatFieldValue: formatFieldValue,
 		}
 
 		logger = zerolog.New(consoleWriter).With().Timestamp().Logger()
 		fileLogger = zerolog.Logger{}
 	})
 }
 
+func formatFieldValue(i any) string {
+	var s string
+
+	switch val := i.(type) {
+	case string:
+		s = val
+	case []byte:
+		s = string(val)
+	default:
+		return fmt.Sprintf("%v", i)
+	}
+
+	if unquoted, err := strconv.Unquote(s); err == nil {
+		s = unquoted
+	}
+
+	if strings.Contains(s, "\n") {
+		return fmt.Sprintf("\n%s", s)
+	}
+
+	if strings.Contains(s, " ") {
+		if (strings.HasPrefix(s, "{") && strings.HasSuffix(s, "}")) ||
+			(strings.HasPrefix(s, "[") && strings.HasSuffix(s, "]")) {
+			return s
+		}
+		return fmt.Sprintf("%q", s)
+	}
+
+	return s
+}
+
 func SetLevel(level LogLevel) {
 	mu.Lock()
 	defer mu.Unlock()
@@ -163,10 +198,7 @@ func logMessage(level LogLevel, component string, message string, fields map[str
 		event.Str("caller", fmt.Sprintf("<none> %s:%d (%s)", callerFile, callerLine, callerFunc))
 	}
 
-	for k, v := range fields {
-		event.Interface(k, v)
-	}
-
+	appendFields(event, fields)
 	event.Msg(message)
 
 	// Also log to file if enabled
@@ -176,9 +208,8 @@ func logMessage(level LogLevel, component string, message string, fields map[str
 		if component != "" {
 			fileEvent.Str("component", component)
 		}
-		for k, v := range fields {
-			fileEvent.Interface(k, v)
-		}
+
+		appendFields(event, fields)
 		fileEvent.Msg(message)
 	}
 
@@ -187,6 +218,26 @@ func logMessage(level LogLevel, component string, message string, fields map[str
 	}
 }
 
+func appendFields(event *zerolog.Event, fields map[string]any) {
+	for k, v := range fields {
+		// Type switch to avoid double JSON serialization of strings
+		switch val := v.(type) {
+		case string:
+			event.Str(k, val)
+		case int:
+			event.Int(k, val)
+		case int64:
+			event.Int64(k, val)
+		case float64:
+			event.Float64(k, val)
+		case bool:
+			event.Bool(k, val)
+		default:
+			event.Interface(k, v) // Fallback for struct, slice and maps
+		}
+	}
+}
+
 func Debug(message string) {
 	logMessage(DEBUG, "", message, nil)
 }

pkg/logger/logger_test.go

@@ -141,3 +141,114 @@ func TestLoggerHelperFunctions(t *testing.T) {
 	Debugf("test from %v", "Debugf")
 	WarnF("Warning with fields", map[string]any{"key": "value"})
 }
+
+func TestFormatFieldValue(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    any
+		expected string
+	}{
+		// Basic types test (default case of the switch)
+		{
+			name:     "Integer Type",
+			input:    42,
+			expected: "42",
+		},
+		{
+			name:     "Boolean Type",
+			input:    true,
+			expected: "true",
+		},
+		{
+			name:     "Unsupported Struct Type",
+			input:    struct{ A int }{A: 1},
+			expected: "{1}",
+		},
+
+		// Simple strings and byte slices test
+		{
+			name:     "Simple string without spaces",
+			input:    "simple_value",
+			expected: "simple_value",
+		},
+		{
+			name:     "Simple byte slice",
+			input:    []byte("byte_value"),
+			expected: "byte_value",
+		},
+
+		// Unquoting test (strconv.Unquote)
+		{
+			name:     "Quoted string",
+			input:    `"quoted_value"`,
+			expected: "quoted_value",
+		},
+
+		// Strings with newline (\n) test
+		{
+			name:     "String with newline",
+			input:    "line1\nline2",
+			expected: "\nline1\nline2",
+		},
+		{
+			name:     "Quoted string with newline (Unquote -> newline)",
+			input:    `"line1\nline2"`, // Escaped \n that Unquote will resolve
+			expected: "\nline1\nline2",
+		},
+
+		// Strings with spaces test (which should be quoted)
+		{
+			name:     "String with spaces",
+			input:    "hello world",
+			expected: `"hello world"`,
+		},
+		{
+			name:     "Quoted string with spaces (Unquote -> has spaces -> Re-quote)",
+			input:    `"hello world"`,
+			expected: `"hello world"`,
+		},
+
+		// JSON formats test (strings with spaces that start/end with brackets)
+		{
+			name:     "Valid JSON object",
+			input:    `{"key": "value"}`,
+			expected: `{"key": "value"}`,
+		},
+		{
+			name:     "Valid JSON array",
+			input:    `[1, 2, "three"]`,
+			expected: `[1, 2, "three"]`,
+		},
+		{
+			name:     "Fake JSON (starts with { but doesn't end with })",
+			input:    `{"key": "value"`, // Missing closing bracket, has spaces
+			expected: `"{\"key\": \"value\""`,
+		},
+		{
+			name:     "Empty JSON (object)",
+			input:    `{ }`,
+			expected: `{ }`,
+		},
+
+		// 7. Edge Cases
+		{
+			name:     "Empty string",
+			input:    "",
+			expected: "",
+		},
+		{
+			name:     "Whitespace only string",
+			input:    "   ",
+			expected: `"   "`,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			actual := formatFieldValue(tt.input)
+			if actual != tt.expected {
+				t.Errorf("formatFieldValue() = %q, expected %q", actual, tt.expected)
+			}
+		})
+	}
+}