refactor(simapp,confix): change example of custom app.toml extension (backport #18496) (#18497)

Co-authored-by: Julien Robert <julien@rbrt.fr>

simapp/simd/cmd/commands.go

@@ -51,19 +51,18 @@ func initCometBFTConfig() *cmtcfg.Config {
 func initAppConfig() (string, interface{}) {
 	// The following code snippet is just for reference.
 
-	// WASMConfig defines configuration for the wasm module.
-	type WASMConfig struct {
-		// This is the maximum sdk gas (wasm and storage) that we allow for any x/wasm "smart" queries
-		QueryGasLimit uint64 `mapstructure:"query_gas_limit"`
-
-		// Address defines the gRPC-web server to listen on
-		LruSize uint64 `mapstructure:"lru_size"`
+	// CustomConfig defines an arbitrary custom config to extend app.toml.
+	// If you don't need it, you can remove it.
+	// If you wish to add fields that correspond to flags that aren't in the SDK server config,
+	// this custom config can as well help.
+	type CustomConfig struct {
+		CustomField string `mapstructure:"custom-field"`
 	}
 
 	type CustomAppConfig struct {
 		serverconfig.Config `mapstructure:",squash"`
 
-		WASM WASMConfig `mapstructure:"wasm"`
+		Custom CustomConfig `mapstructure:"custom"`
 	}
 
 	// Optionally allow the chain developer to overwrite the SDK's default
@@ -77,28 +76,29 @@ func initAppConfig() (string, interface{}) {
 	// In summary:
 	// - if you leave srvCfg.MinGasPrices = "", all validators MUST tweak their
 	//   own app.toml config,
-	// - if you set srvCfg.MinGasPrices non-empty, validators CAN tweak their
+	// - if you set srvCfg.MinGasPrices non-empty, validatorcan be used to extend the app.toml.s CAN tweak their
 	//   own app.toml to override, or use this default value.
 	//
 	// In simapp, we set the min gas prices to 0.
 	srvCfg.MinGasPrices = "0stake"
 	// srvCfg.BaseConfig.IAVLDisableFastNode = true // disable fastnode by default
 
+	// Now we set the custom config default values.
 	customAppConfig := CustomAppConfig{
 		Config: *srvCfg,
-		WASM: WASMConfig{
-			LruSize:       1,
-			QueryGasLimit: 300000,
+		Custom: CustomConfig{
+			CustomField: "anything",
 		},
 	}
 
+	// The default SDK app template is defined in serverconfig.DefaultConfigTemplate.
+	// We append the custom config template to the default one.
+	// And we set the default config to the custom app template.
 	customAppTemplate := serverconfig.DefaultConfigTemplate + `
-[wasm]
-# This is the maximum sdk gas (wasm and storage) that we allow for any x/wasm "smart" queries
-query_gas_limit = {{ .WASM.QueryGasLimit }}
-# This is the number of wasm vm instances we keep cached in memory for speed-up
-# Warning: this is currently unstable and may lead to crashes, best to keep for 0 unless testing locally
-lru_size = {{ .WASM.LruSize }}`
+[custom]
+# That field will be parsed by server.InterceptConfigsPreRunHandler and held by viper.
+# Do not forget to add quotes around the value if it is a string.
+custom-field = "{{ .Custom.CustomField }}"`
 
 	return customAppTemplate, customAppConfig
 }