cmd, core, plugins: introduce config struct, allow user flags

cmd/utils/flags.go

@@ -981,7 +981,12 @@ func ExExPluginFlags() []cli.Flag {
 	for _, name := range exex.Plugins() {
 		flagset = append(flagset, &cli.BoolFlag{
 			Name:     fmt.Sprintf("exex.%s", name),
-			Usage:    fmt.Sprintf("Enables the %s execution extension plugin", name),
+			Usage:    fmt.Sprintf("Enables the '%s' execution extension plugin", name),
+			Category: flags.ExExCategory,
+		})
+		flagset = append(flagset, &cli.StringFlag{
+			Name:     fmt.Sprintf("exex.%s.config", name),
+			Usage:    fmt.Sprintf("Opaque config to pass to the '%s' execution extension plugin", name),
 			Category: flags.ExExCategory,
 		})
 	}
@@ -1925,14 +1930,18 @@ func SetEthConfig(ctx *cli.Context, stack *node.Node, cfg *ethconfig.Config) {
 	}
 	// Execution extension plugins
 	for _, flag := range ExExPluginFlags() {
-		if ctx.IsSet(flag.(*cli.BoolFlag).Name) {
+		if flag, ok := flag.(*cli.BoolFlag); ok {
-			plugin := strings.TrimLeft(flag.(*cli.BoolFlag).Name, "exex.") // TODO(karalabe): Custom flag
+			if ctx.IsSet(flag.Name) {
-			if err := exex.Instantiate(plugin); err != nil {
+				plugin := strings.TrimLeft(flag.Name, "exex.") // TODO(karalabe): Custom flag
+				config := ctx.String(flag.Name + ".config")    // TODO(karalabe): Custom flag
+
+				if err := exex.Instantiate(plugin, config); err != nil {
 					Fatalf("Failed to instantiate ExEx plugin %s: %v", plugin, err)
 				}
 				log.Info("Instantiated ExEx plugin", "name", plugin)
 			}
 		}
+	}
 }
 
 // SetDNSDiscoveryDefaults configures DNS discovery with the given URL if
@@ -2223,14 +2232,18 @@ func MakeChain(ctx *cli.Context, stack *node.Node, readonly bool) (*core.BlockCh
 		}
 	}
 	for _, flag := range ExExPluginFlags() {
-		if ctx.IsSet(flag.(*cli.BoolFlag).Name) {
+		if flag, ok := flag.(*cli.BoolFlag); ok {
-			plugin := strings.TrimLeft(flag.(*cli.BoolFlag).Name, "exex.") // TODO(karalabe): Custom flag
+			if ctx.IsSet(flag.Name) {
-			if err := exex.Instantiate(plugin); err != nil {
+				plugin := strings.TrimLeft(flag.Name, "exex.") // TODO(karalabe): Custom flag
+				config := ctx.String(flag.Name + ".config")    // TODO(karalabe): Custom flag
+
+				if err := exex.Instantiate(plugin, config); err != nil {
 					Fatalf("Failed to instantiate ExEx plugin %s: %v", plugin, err)
 				}
 				log.Info("Instantiated ExEx plugin", "name", plugin)
 			}
 		}
+	}
 	// Disable transaction indexing/unindexing by default.
 	chain, err := core.NewBlockChain(chainDb, cache, gspec, nil, engine, vmcfg, nil)
 	if err != nil {

core/exex/exex.go

@@ -27,7 +27,15 @@ func RegisterV1(name string, constructor NewPluginV1) {
 }
 
 // NewPluginV1 is the constructor signature for making a new plugin.
-type NewPluginV1 func(logger log.Logger) (*PluginV1, error)
+type NewPluginV1 func(config *ConfigV1) (*PluginV1, error)
+
+// ConfigV1 contains some configurations for initializing exex plugins. Some of
+// the fields originate from Geth, other fields from user configs.
+type ConfigV1 struct {
+	Logger log.Logger // Geth's logger with the plugin name injected
+
+	User string // Opaque flag provided by the user on the CLI
+}
 
 // PluginV1 is an Execution Extension module that can be injected into Geth's
 // processing pipeline to subscribe to different node, chain and EVM lifecycle

core/exex/exex/registry.go

@@ -33,7 +33,7 @@ func init() {
 // triggers to be invoked.
 type registry interface {
 	Plugins() []string
-	Instantiate(name string) error
+	Instantiate(name string, userconf string) error
 
 	TriggerInitHook(chain exex.Chain)
 	TriggerCloseHook()
@@ -46,8 +46,8 @@ func Plugins() []string {
 }
 
 // Instantiate constructs an execution extension plugin from a unique name.
-func Instantiate(name string) error {
+func Instantiate(name string, userconf string) error {
-	return globalRegistry.Instantiate(name)
+	return globalRegistry.Instantiate(name, userconf)
 }
 
 // TriggerInitHook triggers the OnInit hook in exex plugins.

core/exex/registry_internal.go

@@ -35,10 +35,13 @@ func (reg *registry) Plugins() []string {
 }
 
 // Instantiate constructs an execution extension plugin from a unique name.
-func (reg *registry) Instantiate(name string) error {
+func (reg *registry) Instantiate(name string, userconf string) error {
 	// Try instantiating a V1 plugin
 	if constructor, ok := globalRegistry.pluginsMakersV1[name]; ok {
-		plugin, err := constructor(log.New("exex", name))
+		plugin, err := constructor(&ConfigV1{
+			Logger: log.New("exex", name),
+			User:   userconf,
+		})
 		if err != nil {
 			return err
 		}

plugins/minimal.go

@@ -19,7 +19,6 @@ package plugins
 import (
 	"github.com/ethereum/go-ethereum/core/exex"
 	"github.com/ethereum/go-ethereum/core/types"
-	"github.com/ethereum/go-ethereum/log"
 )
 
 // Register the minimal ExEx plugin into Geth.
@@ -29,10 +28,10 @@ func init() {
 
 // newMinimalPlugin creates a minimal Execution Extension plugin to react to some
 // chain events.
-func newMinimalPlugin(logger log.Logger) (*exex.PluginV1, error) {
+func newMinimalPlugin(config *exex.ConfigV1) (*exex.PluginV1, error) {
 	return &exex.PluginV1{
 		OnHead: func(head *types.Header) {
-			logger.Info("Chain head updated", "number", head.Number, "hash", head.Hash())
+			config.Logger.Info("Chain head updated", "number", head.Number, "hash", head.Hash())
 		},
 	}, nil
 }