internal/rosa: track evaluation time

Useful to track performance regressions over migrations.

Signed-off-by: Ophestra <cat@gensokyo.uk>

cmd/mbf/main.go

@@ -84,12 +84,17 @@ func main() {
 		flagArch  string
 		flagCheck bool
 		flagLTO   bool
+		flagET    bool
 
 		flagCrossOverride int
 
 		addr net.UnixAddr
 	)
 	c := command.New(os.Stderr, log.Printf, "mbf", func([]string) error {
+		if flagET {
+			log.Println("evaluated in", rosa.EvalTime())
+		}
+
 		msg.SwapVerbose(!flagQuiet)
 		cm.ctx, cm.msg = ctx, msg
 		cm.base = os.ExpandEnv(cm.base)
@@ -183,6 +188,10 @@ func main() {
 		&addr.Name,
 		"socket", command.StringFlag("$MBF_DAEMON_SOCKET"),
 		"Pathname of socket to bind to",
+	).Flag(
+		&flagET,
+		"eval-time", command.BoolFlag(false),
+		"Print duration of the initial azalea evaluation",
 	)
 
 	c.NewCommand(