docs: demonstrate how to define hooks using depinject (backport #21892) (#22132)

Co-authored-by: Eric Mokaya <4112301+ziscky@users.noreply.github.com>
2024-10-04 17:42:25 +02:00
parent 0768b9b0bd
commit 10c19a2592
7 changed files with 169 additions and 5 deletions
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+---
+sidebar_position: 1
+---
+
+# Hooks
+
+Hooks are functions that are called before and/or after certain events in the module's lifecycle.
+
+## Defining Hooks
+
+1. Define the hook interface and a wrapper implementing `depinject.OnePerModuleType`:
+
+    ```go reference
+    https://github.com/cosmos/cosmos-sdk/blob/71c603a2a5a103df00f216d78ec8b108ed64ae28/testutil/x/counter/types/expected_keepers.go#L5-L12
+    ```
+
+2. Add a `CounterHooks` field to the keeper:
+
+    ```go reference
+    https://github.com/cosmos/cosmos-sdk/blob/71c603a2a5a103df00f216d78ec8b108ed64ae28/testutil/x/counter/keeper/keeper.go#L25
+    
+    ```
+
+3. Create a `depinject` invoker function
+
+    ```go reference
+    https://github.com/cosmos/cosmos-sdk/blob/71c603a2a5a103df00f216d78ec8b108ed64ae28/testutil/x/counter/depinject.go#L53-L75   
+    ```
+
+4. Inject the hooks during app initialization:
+
+    ```go
+    appConfig = appconfig.Compose(&appv1alpha1.Config{
+        Modules: []*appv1alpha1.ModuleConfig{
+            // ....
+            {
+                Name:   types.ModuleName,
+                Config: appconfig.WrapAny(&types.Module{}),
+            },
+        }
+    })
+    appConfig = depinject.Configs(
+        AppConfig(),
+        runtime.DefaultServiceBindings(),
+        depinject.Supply(
+            logger,
+            viper,
+            map[string]types.CounterHooksWrapper{
+                "counter": types.CounterHooksWrapper{&types.Hooks{}},
+            },
+    ))
+    ```
+
+## Examples in the SDK
+
+For examples of hooks implementation in the Cosmos SDK, refer to the [Epochs Hooks documentation](https://docs.cosmos.network/main/build/modules/epochs#hooks) and [Distribution Hooks Documentation](https://docs.cosmos.network/main/build/modules/distribution#hooks). 
+