cmd/geth: set up cache and metrics when starting node (#19911)

cmd/geth/consolecmd.go

@@ -77,6 +77,7 @@ JavaScript API. See https://github.com/ethereum/go-ethereum/wiki/JavaScript-Cons
 // same time.
 func localConsole(ctx *cli.Context) error {
 	// Create and start the node based on the CLI flags
+	prepare(ctx)
 	node := makeFullNode(ctx)
 	startNode(ctx, node)
 	defer node.Close()

cmd/geth/main.go

@@ -242,6 +242,26 @@ func init() {
 		if err := debug.Setup(ctx, logdir); err != nil {
 			return err
 		}
+		return nil
+	}
+
+	app.After = func(ctx *cli.Context) error {
+		debug.Exit()
+		console.Stdin.Close() // Resets terminal mode.
+		return nil
+	}
+}
+
+func main() {
+	if err := app.Run(os.Args); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}
+
+// prepare manipulates memory cache allowance and setups metric system.
+// This function should be called before launching devp2p stack.
+func prepare(ctx *cli.Context) {
 	// If we're a full node on mainnet without --cache specified, bump default cache allowance
 	if ctx.GlobalString(utils.SyncModeFlag.Name) != "light" && !ctx.GlobalIsSet(utils.CacheFlag.Name) && !ctx.GlobalIsSet(utils.NetworkIdFlag.Name) {
 		// Make sure we're not on any supported preconfigured testnet either
@@ -281,22 +301,6 @@ func init() {
 
 	// Start system runtime metrics collection
 	go metrics.CollectProcessMetrics(3 * time.Second)
-
-		return nil
-	}
-
-	app.After = func(ctx *cli.Context) error {
-		debug.Exit()
-		console.Stdin.Close() // Resets terminal mode.
-		return nil
-	}
-}
-
-func main() {
-	if err := app.Run(os.Args); err != nil {
-		fmt.Fprintln(os.Stderr, err)
-		os.Exit(1)
-	}
 }
 
 // geth is the main entry point into the system if no special subcommand is ran.
@@ -306,6 +310,7 @@ func geth(ctx *cli.Context) error {
 	if args := ctx.Args(); len(args) > 0 {
 		return fmt.Errorf("invalid command: %q", args[0])
 	}
+	prepare(ctx)
 	node := makeFullNode(ctx)
 	defer node.Close()
 	startNode(ctx, node)