R4R: add events to pricefeed module (#343)

* added events, attributes to pricefeed msgs and core functionality

* removed added space

* conditionally emit market_price_updated if price has changed

* updated expiry to Unix format

x/pricefeed/alias.go

@@ -17,7 +17,14 @@ const (
 	CodeInvalidPrice              = types.CodeInvalidPrice
 	CodeInvalidAsset              = types.CodeInvalidAsset
 	CodeInvalidOracle             = types.CodeInvalidOracle
+	EventTypeMarketPriceUpdated   = types.EventTypeMarketPriceUpdated
+	EventTypeOracleUpdatedPrice   = types.EventTypeOracleUpdatedPrice
 	EventTypeNoValidPrices        = types.EventTypeNoValidPrices
+	AttributeValueCategory        = types.AttributeValueCategory
+	AttributeMarketID             = types.AttributeMarketID
+	AttributeMarketPrice          = types.AttributeMarketPrice
+	AttributeOracle               = types.AttributeOracle
+	AttributeExpiry               = types.AttributeExpiry
 	AttributeKeyPriceUpdateFailed = types.AttributeKeyPriceUpdateFailed
 	ModuleName                    = types.ModuleName
 	StoreKey                      = types.StoreKey

x/pricefeed/handler.go

@@ -36,5 +36,14 @@ func HandleMsgPostPrice(
 	if err != nil {
 		return err.Result()
 	}
-	return sdk.Result{}
+
+	ctx.EventManager().EmitEvent(
+		sdk.NewEvent(
+			sdk.EventTypeMessage,
+			sdk.NewAttribute(sdk.AttributeKeyModule, AttributeValueCategory),
+			sdk.NewAttribute(sdk.AttributeKeySender, msg.From.String()),
+		),
+	)
+
+	return sdk.Result{Events: ctx.EventManager().Events()}
 }

x/pricefeed/keeper/keeper.go

@@ -1,6 +1,7 @@
 package keeper
 
 import (
+	"fmt"
 	"sort"
 	"time"
 
@@ -67,6 +68,16 @@ func (k Keeper) SetPrice(
 			index = len(prices) - 1
 		}
 
+		// Emit an event containing the oracle's new price
+		ctx.EventManager().EmitEvent(
+			sdk.NewEvent(
+				types.EventTypeOracleUpdatedPrice,
+				sdk.NewAttribute(types.AttributeMarketID, marketID),
+				sdk.NewAttribute(types.AttributeOracle, oracle.String()),
+				sdk.NewAttribute(types.AttributeMarketPrice, price.String()),
+				sdk.NewAttribute(types.AttributeExpiry, fmt.Sprintf("%d", expiry.Unix())),
+			),
+		)
 		store.Set(
 			[]byte(types.RawPriceFeedPrefix+marketID), k.cdc.MustMarshalBinaryBare(prices),
 		)
@@ -76,12 +87,19 @@ func (k Keeper) SetPrice(
 
 }
 
-// SetCurrentPrices updates the price of an asset to the meadian of all valid oracle inputs
+// SetCurrentPrices updates the price of an asset to the median of all valid oracle inputs
 func (k Keeper) SetCurrentPrices(ctx sdk.Context, marketID string) sdk.Error {
 	_, ok := k.GetMarket(ctx, marketID)
 	if !ok {
 		return types.ErrInvalidMarket(k.codespace, marketID)
 	}
+	// store current price
+	validPrevPrice := true
+	prevPrice, err := k.GetCurrentPrice(ctx, marketID)
+	if err != nil {
+		validPrevPrice = false
+	}
+
 	prices := k.GetRawPrices(ctx, marketID)
 	var notExpiredPrices []types.CurrentPrice
 	// filter out expired prices
@@ -102,11 +120,26 @@ func (k Keeper) SetCurrentPrices(ctx sdk.Context, marketID string) sdk.Error {
 	}
 	medianPrice := k.CalculateMedianPrice(ctx, notExpiredPrices)
 
+	// check case that market price was not set in genesis
+	if validPrevPrice {
+		// only emit event if price has changed
+		if !medianPrice.Equal(prevPrice.Price) {
+			ctx.EventManager().EmitEvent(
+				sdk.NewEvent(
+					types.EventTypeMarketPriceUpdated,
+					sdk.NewAttribute(types.AttributeMarketID, fmt.Sprintf("%s", marketID)),
+					sdk.NewAttribute(types.AttributeMarketPrice, fmt.Sprintf("%s", medianPrice.String())),
+				),
+			)
+		}
+	}
+
 	store := ctx.KVStore(k.key)
 	currentPrice := types.CurrentPrice{
 		MarketID: marketID,
 		Price:    medianPrice,
 	}
+
 	store.Set(
 		[]byte(types.CurrentPricePrefix+marketID), k.cdc.MustMarshalBinaryBare(currentPrice),
 	)

x/pricefeed/types/events.go

@@ -2,7 +2,14 @@ package types
 
 // Pricefeed module event types
 const (
-	EventTypeNoValidPrices = "no_valid_prices"
+	EventTypeMarketPriceUpdated = "market_price_updated"
+	EventTypeOracleUpdatedPrice = "oracle_updated_price"
+	EventTypeNoValidPrices      = "no_valid_prices"
 
+	AttributeValueCategory        = ModuleName
+	AttributeMarketID             = "market_id"
+	AttributeMarketPrice          = "market_price"
+	AttributeOracle               = "oracle"
+	AttributeExpiry               = "expiry"
 	AttributeKeyPriceUpdateFailed = "price_update_failed"
 )