fix database connection leak, disable default prometheus metrics

package.json

@@ -12,5 +12,8 @@
     "express": "^4.17.1",
     "pg": "^8.5.1",
     "prom-client": "^12.0.0"
+  },
+  "scripts": {
+    "start": "node ./src/index.js"
   }
 }

src/index.js

@@ -24,14 +24,21 @@ const startServer = () => {
     server.listen(serverPort, serverHost, () => console.log(`Http server running on port ${serverHost}:${serverPort}`));
 }
 
-const run = async () => {
+let dbStateDiff;
+
+const connectToDB = () => {
     const statediffUser = process.env.STATEDIFF_PG_USER;
     const statediffPassword = process.env.STATEDIFF_PG_PASSWORD;
     const statediffDB = process.env.STATEDIFF_PG_DATABASE;
     const statediffHost = process.env.STATEDIFF_PG_HOST;
     const statediffPort = process.env.STATEDIFF_PG_PORT;
 
-    const dbStateDiff = new DB('statediff', statediffUser, statediffPassword, statediffDB, statediffHost, statediffPort)
+    dbStateDiff = new DB('statediff', statediffUser, statediffPassword, statediffDB, statediffHost, statediffPort)
+}
+
+const run = async () => {
+
+    // statediff database
     const dbStateDiffBlockNumber = dbStateDiff.getBlockNumber();
 
     // Etherscan
@@ -71,6 +78,7 @@ const sleep = ms => new Promise(resolve => setTimeout(resolve, ms));
 
 const main = async () => {
     startServer();
+    connectToDB();
 
     let lock = false;
 

src/prometheus.js

@@ -1,10 +1,8 @@
 const client = require('prom-client');
 
-const collectDefaultMetrics = client.collectDefaultMetrics;
 const Registry = client.Registry;
 const register = new Registry();
 const prefix = 'eth_state_metrics_';
-collectDefaultMetrics({ register });
 
 const etherscanGauge = new client.Gauge({ name: `${prefix}etherscan`, help: 'Etherscan Block Number', registers: [register]});
 const statediffDBGauge = new client.Gauge({ name: `${prefix}statediff_db`, help: 'Statediff DB Block Number', registers: [register]});