The Cosmos SDK allows much easier wiring of an app.go thanks to runtime and app wiring. Learn more about the rationale of App Wiring in ADR-057.
This section is intended to provide an overview of the SimApp app_di.go file with App Wiring.

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app_config.go​

The app_config.go file is the single place to configure all modules parameters.
  1. Create the AppConfig variable: simapp/app_config.go 
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    See full example on GitHub Where the appConfig combines the runtime configuration and the (extra) modules configuration. simapp/app_di.go 
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    See full example on GitHub
  2. Configure the runtime module: In this configuration, the order at which the modules are defined in PreBlockers, BeginBlocks, and EndBlockers is important. They are named in the order they should be executed by the module manager. simapp/app_config.go 
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    See full example on GitHub
  3. Wire the other modules: Next to runtime, the other (depinject-enabled) modules are wired in the AppConfig: simapp/app_config.go 
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    See full example on GitHub Note: the tx isn’t a module, but a configuration. It should be wired in the AppConfig as well. simapp/app_config.go 
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    See full example on GitHub
See the complete app_config.go file for SimApp here.

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Alternative formats​

The example above shows how to create an AppConfig using Go. However, it is also possible to create an AppConfig using YAML, or JSON. The configuration can then be embed with go:embed and read with appconfig.LoadYAML, or appconfig.LoadJSON, in app_di.go.
//go:embed app_config.yamlvar (    appConfigYaml []byte    appConfig = appconfig.LoadYAML(appConfigYaml))

modules:  - name: runtime    config:      "@type": cosmos.app.runtime.v1alpha1.Module      app_name: SimApp      begin_blockers: [staking, auth, bank]      end_blockers: [bank, auth, staking]      init_genesis: [bank, auth, staking]  - name: auth    config:      "@type": cosmos.auth.module.v1.Module      bech32_prefix: cosmos  - name: bank    config:      "@type": cosmos.bank.module.v1.Module  - name: staking    config:      "@type": cosmos.staking.module.v1.Module  - name: tx    config:      "@type": cosmos.tx.module.v1.Module
A more complete example of app.yaml can be found here.

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app_di.go​

app_di.go is the place where SimApp is constructed. depinject.Inject automatically wires the app modules and keepers when provided with an application configuration (AppConfig). SimApp is constructed upon calling the injected *runtime.AppBuilder with appBuilder.Build(...). In short depinject and the runtime package abstract the wiring of the app, and the AppBuilder is the place where the app is constructed. runtime takes care of registering the codecs, KV store, subspaces and instantiating baseapp. simapp/app_di.go 
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See full example on GitHub
When using depinject.Inject, the injected types must be pointers.

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Advanced Configuration​

In advanced cases, it is possible to inject extra (module) configuration in a way that is not (yet) supported by AppConfig. In this case, use depinject.Configs for combining the extra configuration, and AppConfig and depinject.Supply for providing the extra configuration. More information on how depinject.Configs and depinject.Supply function can be found in the depinject documentation. simapp/app_di.go 
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See full example on GitHub

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Registering non app wiring modules​

It is possible to combine app wiring / depinject enabled modules with non-app wiring modules. To do so, use the app.RegisterModules method to register the modules on your app, as well as app.RegisterStores for registering the extra stores needed. 
// ....app.App = appBuilder.Build(db, traceStore, baseAppOptions...)// register module manuallyapp.RegisterStores(storetypes.NewKVStoreKey(example.ModuleName))app.ExampleKeeper = examplekeeper.NewKeeper(app.appCodec, app.AccountKeeper.AddressCodec(), runtime.NewKVStoreService(app.GetKey(example.ModuleName)), authtypes.NewModuleAddress(govtypes.ModuleName).String())exampleAppModule := examplemodule.NewAppModule(app.ExampleKeeper)if err := app.RegisterModules(&exampleAppModule); err != nil {    panic(err)}// ....
When using AutoCLI and combining app wiring and non-app wiring modules. The AutoCLI options should be manually constructed instead of injected. Otherwise it will miss the non depinject modules and not register their CLI.

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Complete app_di.go​

Note that in the complete SimApp app_di.go file, testing utilities are also defined, but they could as well be defined in a separate file.
simapp/app_di.go 
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See full example on GitHub