feat: add hook(s) for the farming module

x/farming/keeper/hooks.go

@@ -0,0 +1,17 @@
+package keeper
+
+import (
+	sdk "github.com/cosmos/cosmos-sdk/types"
+
+	"github.com/cosmosquad-labs/squad/v2/x/farming/types"
+)
+
+// Implements FarmingHooks interface
+var _ types.FarmingHooks = Keeper{}
+
+// AfterAllocateRewards - call hook if registered
+func (k Keeper) AfterAllocateRewards(ctx sdk.Context) {
+	if k.hooks != nil {
+		k.hooks.AfterAllocateRewards(ctx)
+	}
+}

x/farming/keeper/hooks_test.go

@@ -0,0 +1,43 @@
+package keeper_test
+
+import (
+	sdk "github.com/cosmos/cosmos-sdk/types"
+
+	"github.com/cosmosquad-labs/squad/v2/x/farming/types"
+
+	_ "github.com/stretchr/testify/suite"
+)
+
+var _ types.FarmingHooks = (*MockFarmingHooksReceiver)(nil)
+
+// MockFarmingHooksReceiver event hooks for farming object (noalias)
+type MockFarmingHooksReceiver struct {
+	AfterAllocateRewardsValid bool
+}
+
+func (h *MockFarmingHooksReceiver) AfterAllocateRewards(ctx sdk.Context) {
+	h.AfterAllocateRewardsValid = true
+}
+
+func (s *KeeperTestSuite) TestHooks() {
+	farmingHooksReceiver := MockFarmingHooksReceiver{}
+
+	// Set hooks
+	s.keeper.SetHooks(types.NewMultiFarmingHooks(&farmingHooksReceiver))
+
+	// Default must be false
+	s.Require().False(farmingHooksReceiver.AfterAllocateRewardsValid)
+
+	// Create sample farming plan
+	s.CreateFixedAmountPlan(s.addrs[5], map[string]string{denom1: "1"}, map[string]int64{denom3: 700000})
+
+	// Stake
+	s.Stake(s.addrs[0], sdk.NewCoins(sdk.NewInt64Coin(denom1, 1000000)))
+
+	// Advanced epoch twice to trigger AllocateRewards function
+	s.advanceEpochDays()
+	s.advanceEpochDays()
+
+	// Must be true
+	s.Require().True(farmingHooksReceiver.AfterAllocateRewardsValid)
+}

x/farming/keeper/keeper.go

@@ -47,6 +47,7 @@ type Keeper struct {
 
 	bankKeeper    types.BankKeeper
 	accountKeeper types.AccountKeeper
+	hooks         types.FarmingHooks
 }
 
 // NewKeeper returns a farming keeper. It handles:
@@ -75,6 +76,17 @@ func NewKeeper(cdc codec.BinaryCodec, key sdk.StoreKey, paramSpace paramtypes.Su
 	}
 }
 
+// SetHooks sets the farming hooks.
+func (k *Keeper) SetHooks(fh types.FarmingHooks) *Keeper {
+	if k.hooks != nil {
+		panic("cannot set farming hooks twice")
+	}
+
+	k.hooks = fh
+
+	return k
+}
+
 // Logger returns a module-specific logger.
 func (k Keeper) Logger(ctx sdk.Context) log.Logger {
 	return ctx.Logger().With("module", "x/"+types.ModuleName)

x/farming/keeper/reward.go

@@ -607,6 +607,9 @@ func (k Keeper) AllocateRewards(ctx sdk.Context) error {
 		k.SetCurrentEpoch(ctx, stakingCoinDenom, currentEpoch+1)
 	}
 
+	// Call hook after successfully allocating rewards
+	k.AfterAllocateRewards(ctx)
+
 	return nil
 }
 

x/farming/spec/09_hooks.md

@@ -0,0 +1,11 @@
+<!-- order: 9 -->
+
+# Hooks
+
+Other modules may register operations to execute when a certain event has occurred within farming. 
+These events can be registered to execute right `Before` or `After` the farming event (as per the hook name). 
+The following hooks can be registered:
+
+```go
+AfterAllocateRewards(ctx sdk.Context)
+```

x/farming/spec/README.md

@@ -18,3 +18,4 @@ A primary use case of the farming module is to provide incentives for liquidity
 6. **[Events](06_events.md)**
 7. **[Parameters](07_params.md)**
 8. **[Proposal](08_proposal.md)**
+9. **[Hooks](09_hooks.md)**

x/farming/types/expected_keepers.go

@@ -26,3 +26,12 @@ type AccountKeeper interface {
 	GetAccount(ctx sdk.Context, addr sdk.AccAddress) authtypes.AccountI
 	GetModuleAddress(name string) sdk.AccAddress
 }
+
+// Event hooks
+// These can be utilized to communicate between a farming keeper and other keepers from other modules.
+// The other keepers must implement this interface, which then the farming keeper can call.
+
+// FarmingHooks event hooks for the farming object (noalias)
+type FarmingHooks interface {
+	AfterAllocateRewards(ctx sdk.Context) // Must be called when farming rewards are allocated
+}

x/farming/types/hooks.go

@@ -0,0 +1,19 @@
+package types
+
+import (
+	sdk "github.com/cosmos/cosmos-sdk/types"
+)
+
+// MultiFarmingHooks combines multiple farming hooks.
+// All hook functions are run in array sequence
+type MultiFarmingHooks []FarmingHooks
+
+func NewMultiFarmingHooks(hooks ...FarmingHooks) MultiFarmingHooks {
+	return hooks
+}
+
+func (h MultiFarmingHooks) AfterAllocateRewards(ctx sdk.Context) {
+	for i := range h {
+		h[i].AfterAllocateRewards(ctx)
+	}
+}