feat(price_pusher): add gauge metrics for source and target price values

apps/price_pusher/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@pythnetwork/price-pusher",
-  "version": "10.0.0",
+  "version": "10.1.0",
   "description": "Pyth Price Pusher",
   "homepage": "https://pyth.network",
   "main": "lib/index.js",

apps/price_pusher/src/controller.ts

@@ -61,6 +61,12 @@ export class Controller {
             sourceLatestPrice.publishTime,
             priceConfig.timeDifference,
           );
+          this.metrics.updatePriceValues(
+            priceId,
+            alias,
+            sourceLatestPrice.price,
+            targetLatestPrice.price,
+          );
         }
 
         const priceShouldUpdate = shouldUpdate(

apps/price_pusher/src/metrics.ts

@@ -15,6 +15,8 @@ export class PricePusherMetrics {
   public priceFeedsTotal: Gauge<string>;
   public sourceTimestamp: Gauge<string>;
   public configuredTimeDifference: Gauge<string>;
+  public sourcePriceValue: Gauge<string>;
+  public targetPriceValue: Gauge<string>;
   // Wallet metrics
   public walletBalance: Gauge<string>;
 
@@ -61,6 +63,20 @@ export class PricePusherMetrics {
       registers: [this.registry],
     });
 
+    this.sourcePriceValue = new Gauge({
+      name: "pyth_source_price",
+      help: "Latest price value from Pyth source",
+      labelNames: ["price_id", "alias"],
+      registers: [this.registry],
+    });
+
+    this.targetPriceValue = new Gauge({
+      name: "pyth_target_price",
+      help: "Latest price value from target chain",
+      labelNames: ["price_id", "alias"],
+      registers: [this.registry],
+    });
+
     // Wallet balance metric
     this.walletBalance = new Gauge({
       name: "pyth_wallet_balance",
@@ -158,6 +174,27 @@ export class PricePusherMetrics {
     );
   }
 
+  // Update price values
+  public updatePriceValues(
+    priceId: string,
+    alias: string,
+    sourcePrice: string | undefined,
+    targetPrice: string | undefined,
+  ): void {
+    if (sourcePrice !== undefined) {
+      this.sourcePriceValue.set(
+        { price_id: priceId, alias },
+        Number(sourcePrice),
+      );
+    }
+    if (targetPrice !== undefined) {
+      this.targetPriceValue.set(
+        { price_id: priceId, alias },
+        Number(targetPrice),
+      );
+    }
+  }
+
   // Update wallet balance
   public updateWalletBalance(
     walletAddress: string,