Add wallet tracker

wallet-tracker/.gitignore

@@ -0,0 +1,2 @@
+
+node_modules/

wallet-tracker/Dockerfile

@@ -0,0 +1,7 @@
+FROM node:18
+
+WORKDIR /app
+COPY package.json ./
+RUN npm install
+COPY src src
+CMD ["npm", "start"]

wallet-tracker/package.json

@@ -0,0 +1,15 @@
+{
+  "name": "wallet-tracker",
+  "version": "1.0.0",
+  "description": "",
+  "scripts": {
+    "start": "node --no-warnings=ExperimentalWarning src/main.js",
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "author": "",
+  "license": "ISC",
+  "dependencies": {
+    "express": "^4.18.2",
+    "prom-client": "^15.1.0"
+  }
+}

wallet-tracker/src/main.js

@@ -0,0 +1,24 @@
+const express = require('express');
+const { createMetrics } = require('./metrics');
+const { loadWalletBalance, loadUSDCBalance, extractWalletBalance, extractUSDCBalance } = require('./solana');
+
+const WALLET_ADDRESS = process.env.WALLET_ADDRESS;
+const [registry, usdcBalanceMetric, solBalanceMetric] = createMetrics();
+const app = express();
+
+app.get('/metrics', async (req, res) => {
+    res.setHeader('Content-Type', registry.contentType);
+
+    let [solBalance, usdcBalance] = await Promise.all([
+        loadWalletBalance(WALLET_ADDRESS),
+        loadUSDCBalance(WALLET_ADDRESS)]);
+
+    solBalanceMetric.set(extractWalletBalance(solBalance));
+    usdcBalanceMetric.set(extractUSDCBalance(usdcBalance));
+
+    res.send(await registry.metrics());
+});
+
+app.listen(3000, () => {
+    console.log("Server is running on port 3000");
+});

wallet-tracker/src/metrics.js

@@ -0,0 +1,23 @@
+const client = require('prom-client');
+
+const createMetrics = () => {
+    const registry = new client.Registry();
+
+    const solBalanceMetric = new client.Gauge({
+        name: "sol_balance",
+        help: "SOL Balance",
+    });
+    const usdcBalanceMetric = new client.Gauge({
+        name: "usdc_balance",
+        help: "USDC Balance",
+    });
+
+    registry.registerMetric(usdcBalanceMetric);
+    registry.registerMetric(solBalanceMetric);
+
+    return [registry, usdcBalanceMetric, solBalanceMetric];
+};
+
+module.exports = {
+    createMetrics
+}

wallet-tracker/src/solana.js

@@ -0,0 +1,58 @@
+const LAMPORTS_PER_SOL = 1000000000;
+const SOLANA_RPC = "https://api.mainnet-beta.solana.com/";
+const rpcRequestHeaders = {
+    "Content-Type": "application/json",
+};
+const rpcRequest = (method, params) => {
+    return {
+        jsonrpc: "2.0",
+        id: 1,
+        method: method,
+        params: params,
+    };
+};
+
+// POST request to Solana API to load wallet balance
+async function loadWalletBalance(walletAddress) {
+    const response = await fetch(SOLANA_RPC, {
+        method: "POST",
+        headers: rpcRequestHeaders,
+        body: JSON.stringify(rpcRequest("getBalance", [walletAddress])),
+    });
+    const json = await response.json();
+    return json;
+}
+
+// POST request to Solana API to load USDC balance
+async function loadUSDCBalance(walletAddress) {
+    const response = await fetch(SOLANA_RPC, {
+        method: "POST",
+        headers: rpcRequestHeaders,
+        body: JSON.stringify(
+            rpcRequest("getTokenAccountsByOwner", [
+                walletAddress,
+                { "mint": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v" },
+                { "encoding": "jsonParsed" }])
+        ),
+    });
+    const json = await response.json();
+    return json;
+}
+
+// extract wallet balance
+function extractWalletBalance(walletBalance) {
+    return walletBalance.result.value / LAMPORTS_PER_SOL;
+}
+
+// extract USDC balance
+function extractUSDCBalance(usdcBalance) {
+    return usdcBalance.result.value[0].account.data.parsed.info.tokenAmount.uiAmount;
+}
+
+// export functions
+module.exports = {
+    loadWalletBalance,
+    loadUSDCBalance,
+    extractWalletBalance,
+    extractUSDCBalance
+};