feat: singleton pattern

Author: qwe2tz

src/db/database.ts

@@ -4,29 +4,31 @@ import { NodeProofRate } from "../model/staking/NodeProofRate";
 import { EstimatedReward } from "../model/staking/EstimatedRewards";
 
 
-let AppDataSource: DataSource;
+let AppDataSource: DataSource = null;
 
-export async function initDatabase() {
+export async function initOrGetDatabase() {
   const schema = process.env.DB_SCHEMA || "computed";
 
-  AppDataSource = new DataSource({
-    type: "postgres",
-    host: "postgres",
-    port: parseInt(process.env.DB_PORT) || 5432,
-    username: process.env.DB_USER,
-    password: process.env.DB_PASS,
-    database: process.env.DB_NAME,
-    entities: [CollectedReward, EstimatedReward, NodeProofRate],
-    // This means we always update the database schema to match the entities
-    synchronize: true,
-    schema,
-  });
+  if (!AppDataSource) {
+    AppDataSource = new DataSource({
+      type: "postgres",
+      host: "postgres",
+      port: parseInt(process.env.DB_PORT) || 5432,
+      username: process.env.DB_USER,
+      password: process.env.DB_PASS,
+      database: process.env.DB_NAME,
+      entities: [CollectedReward, EstimatedReward, NodeProofRate],
+      // This means we always update the database schema to match the entities
+      synchronize: true,
+      schema,
+    });
+
+    await AppDataSource.initialize()
+      .then(() => {
+        console.log("[✔] Type ORM Data Source initialized. Using schema:", schema);
+      })
+      .catch((error) => console.log(error));
+  }
 
-  await AppDataSource.initialize()
-    .then(() => {
-      console.log("[✔] Type ORM Data Source initialized. Using schema:", schema);
-    })
-    .catch((error) => console.log(error));
-  
   return AppDataSource;
 }

src/db/index.ts

@@ -1,7 +1,7 @@
-import { initDatabase } from "./database";
+import { initOrGetDatabase } from "./database";
 import { processStakingData } from "./procedures/staking";
 
 export async function processData(blocks: Number[]) {
-  const db = await initDatabase();
+  const db = await initOrGetDatabase();
   await processStakingData(db, blocks);
 }