Set process priority to idle on Windows.

icedreammusic/np/main.go

@@ -18,6 +18,7 @@ import (
 	"github.com/delthas/go-libnp"
 	"github.com/dhowden/tag"
 	"github.com/gin-gonic/gin"
+	"golang.org/x/sys/windows"
 	"gopkg.in/alecthomas/kingpin.v3-unstable"
 
 	"github.com/icedream/livestream-tools/icedreammusic/metacollector"
@@ -61,9 +62,31 @@ func generateIDFromMetadata(metadata libnp.Info) [64]byte {
 	return sha512.Sum512([]byte(strings.Join(metadata.Artists, "|") + "||" + metadata.Title))
 }
 
+// https://learn.microsoft.com/en-us/windows/win32/procthread/process-security-and-access-rights
+const PROCESS_ALL_ACCESS = windows.STANDARD_RIGHTS_REQUIRED | windows.SYNCHRONIZE | 0xffff
+
+func SetPriorityWindows(pid int, priority uint32) error {
+	handle, err := windows.OpenProcess(PROCESS_ALL_ACCESS, false, uint32(pid))
+	if err != nil {
+		return err
+	}
+	defer windows.CloseHandle(handle) // Technically this can fail, but we ignore it if it does
+
+	err = windows.SetPriorityClass(handle, priority)
+	if err != nil {
+		return err
+	}
+}
+
 func main() {
 	ctx := context.Background()
 
+	// Set priority to idle to not use CPU that is required for audio playback
+	err := SetPriorityWindows(os.Getpid(), windows.IDLE_PRIORITY_CLASS)
+	if err != nil {
+		log.Println("WARNING: Failed to set priority class: ", err)
+	}
+
 	ctx, cancel := signal.NotifyContext(ctx, os.Interrupt, syscall.SIGTERM)
 	defer cancel()