feat: colorize http status logs

internal/observability/log.go

@@ -20,7 +20,10 @@ import (
 const (
 	ansiReset      = "\x1b[0m"
 	ansiBlue       = "\x1b[36m"
+	ansiStatusBlue = "\x1b[34m"
+	ansiGreen      = "\x1b[32m"
 	ansiYellow     = "\x1b[33m"
+	ansiOrange     = "\x1b[38;5;208m"
 	ansiRed        = "\x1b[31m"
 )
 
@@ -315,7 +318,7 @@ func popField(fields map[string]any, key string) string {
 func formatInlineField(key string, value any) string {
 	switch key {
 	case "status":
-		return fmt.Sprint(value)
+		return formatHTTPStatus(value)
 	case "duration_ms":
 		return formatDurationMillis(value)
 	case "bytes":
@@ -328,6 +331,28 @@ func formatInlineField(key string, value any) string {
 	}
 }
 
+func formatHTTPStatus(value any) string {
+	status := fmt.Sprint(value)
+	if !colorLogs || len(status) == 0 {
+		return status
+	}
+
+	switch status[0] {
+	case '1':
+		return ansiStatusBlue + status + ansiReset
+	case '2':
+		return ansiGreen + status + ansiReset
+	case '3':
+		return ansiYellow + status + ansiReset
+	case '4':
+		return ansiOrange + status + ansiReset
+	case '5':
+		return ansiRed + status + ansiReset
+	default:
+		return status
+	}
+}
+
 func formatDurationMillis(value any) string {
 	ms, ok := toFloat64(value)
 	if !ok {

internal/observability/log_test.go

@@ -34,3 +34,27 @@ func TestFormatLogEntryFormatsHTTPRequestCompactly(t *testing.T) {
 		t.Fatalf("line should omit loopback ip: %q", line)
 	}
 }
+
+func TestFormatHTTPStatusColorsByStatusFamily(t *testing.T) {
+	previousColorLogs := colorLogs
+	colorLogs = true
+	t.Cleanup(func() {
+		colorLogs = previousColorLogs
+	})
+
+	tests := map[any]string{
+		101:       ansiStatusBlue + "101" + ansiReset,
+		200:       ansiGreen + "200" + ansiReset,
+		302:       ansiYellow + "302" + ansiReset,
+		404:       ansiOrange + "404" + ansiReset,
+		500:       ansiRed + "500" + ansiReset,
+		"unknown": "unknown",
+	}
+
+	for input, want := range tests {
+		got := formatHTTPStatus(input)
+		if got != want {
+			t.Fatalf("formatHTTPStatus(%v) = %q, want %q", input, got, want)
+		}
+	}
+}