From e29a86368f7b6553d48fe7be729f7e6f8089dde5 Mon Sep 17 00:00:00 2001
From: Crystal Lemire <crystal@dydx.exchange>
Date: Wed, 25 Oct 2023 15:20:53 -0700
Subject: [PATCH] Add tracking for market availability in order to alert in
 datadog.

---
 .../client/price_fetcher/price_fetcher.go     | 42 +++++++++++++++++++
 protocol/lib/metrics/constants.go             |  1 +
 2 files changed, 43 insertions(+)

diff --git a/protocol/daemons/pricefeed/client/price_fetcher/price_fetcher.go b/protocol/daemons/pricefeed/client/price_fetcher/price_fetcher.go
index 8a8377b4dd..e685b120f6 100644
--- a/protocol/daemons/pricefeed/client/price_fetcher/price_fetcher.go
+++ b/protocol/daemons/pricefeed/client/price_fetcher/price_fetcher.go
@@ -3,6 +3,7 @@ package price_fetcher
 import (
 	"context"
 	"fmt"
+	"github.com/cosmos/cosmos-sdk/telemetry"
 	daemontypes "github.com/dydxprotocol/v4-chain/protocol/daemons/types"
 	"sync"
 	"time"
@@ -183,6 +184,27 @@ func (pf *PriceFetcher) RunTaskLoop(requestHandler daemontypes.RequestHandler) {
 	}
 }
 
+// logMarketAvailability emits telemetry that tracks whether a market was available when queried on an exchange.
+// Success is tracked by (market, exchange) so that we can track the availability of each market on each exchange.
+func logMarketAvailability(exchangeId types.ExchangeId, id types.MarketId, available bool) {
+	success := metrics.Success
+	if !available {
+		success = metrics.Error
+	}
+	telemetry.IncrCounterWithLabels(
+		[]string{
+			metrics.PricefeedDaemon,
+			metrics.PriceFetcherQueryForMarket,
+			success,
+		},
+		1,
+		[]gometrics.Label{
+			pricefeedmetrics.GetLabelForExchangeId(exchangeId),
+			pricefeedmetrics.GetLabelForMarketId(id),
+		},
+	)
+}
+
 // runSubTask makes a single query to an exchange for market prices. This query can be for 1 or
 // n markets.
 // For single market exchanges, a task loop execution will execute multiple runSubTask goroutines, where
@@ -239,9 +261,21 @@ func (pf *PriceFetcher) runSubTask(
 
 	if err != nil {
 		pf.writeToBufferedChannel(exchangeId, nil, err)
+
+		// Since the query failed, report all markets as unavailable.
+		for _, marketId := range marketIds {
+			logMarketAvailability(exchangeId, marketId, false)
+		}
+
 		return
 	}
 
+	// Track which markets were available when queried, and which were not, for telemetry.
+	availableMarkets := make(map[types.MarketId]bool, len(marketIds))
+	for _, marketId := range marketIds {
+		availableMarkets[marketId] = false
+	}
+
 	for _, price := range prices {
 		// No price should validly be zero. A price of zero points to an error in the API queried.
 		if price.Price == uint64(0) {
@@ -269,8 +303,16 @@ func (pf *PriceFetcher) runSubTask(
 			price.LastUpdatedAt,
 		)
 
+		// Report market as available.
+		availableMarkets[price.MarketId] = true
+
 		pf.writeToBufferedChannel(exchangeId, price, err)
 	}
+
+	// Emit metrics on this exchange's market availability.
+	for marketId, available := range availableMarkets {
+		logMarketAvailability(exchangeId, marketId, available)
+	}
 }
 
 // writeToBufferedChannel writes the (price, error) generated during querying to the price fetcher's
diff --git a/protocol/lib/metrics/constants.go b/protocol/lib/metrics/constants.go
index 7e03df2b34..77ea2e5ef2 100644
--- a/protocol/lib/metrics/constants.go
+++ b/protocol/lib/metrics/constants.go
@@ -343,6 +343,7 @@ const (
 	MarketUpdaterUpdateMarkets              = "market_updater_update_markets"
 	PriceEncoderPriceConversion             = "price_encoder_price_conversion"
 	PriceFetcherQueryExchange               = "price_fetcher_query_exchange"
+	PriceFetcherQueryForMarket              = "price_fetcher_query_for_market"
 	PriceFetcherSubtaskLoop                 = "price_fetcher_subtask_loop"
 	PriceFetcherSubtaskLoopAndSetCtxTimeout = "price_fetcher_subtask_loop_and_set_ctx_timeout"
 	PriceUpdateCount                        = "price_update_count"