app: add code for macOS and Windows apps under 'app' (#12933)

* app: add code for macOS and Windows apps under 'app'

* app: add readme

* app: windows and linux only for now

* ci: fix ui CI validation

---------

Co-authored-by: jmorganca <jmorganca@gmail.com>

app/logrotate/logrotate.go

@@ -0,0 +1,45 @@
+//go:build windows || darwin
+
+// package logrotate provides utilities for rotating logs
+// TODO (jmorgan): this most likely doesn't need it's own
+// package and can be moved to app where log files are created
+package logrotate
+
+import (
+	"log/slog"
+	"os"
+	"strconv"
+	"strings"
+)
+
+const MaxLogFiles = 5
+
+func Rotate(filename string) {
+	if _, err := os.Stat(filename); os.IsNotExist(err) {
+		return
+	}
+
+	index := strings.LastIndex(filename, ".")
+	pre := filename[:index]
+	post := "." + filename[index+1:]
+	for i := MaxLogFiles; i > 0; i-- {
+		older := pre + "-" + strconv.Itoa(i) + post
+		newer := pre + "-" + strconv.Itoa(i-1) + post
+		if i == 1 {
+			newer = pre + post
+		}
+		if _, err := os.Stat(newer); err == nil {
+			if _, err := os.Stat(older); err == nil {
+				err := os.Remove(older)
+				if err != nil {
+					slog.Warn("Failed to remove older log", "older", older, "error", err)
+					continue
+				}
+			}
+			err := os.Rename(newer, older)
+			if err != nil {
+				slog.Warn("Failed to rotate log", "older", older, "newer", newer, "error", err)
+			}
+		}
+	}
+}