Merge pull request #6 from leetcode-roulette/feature/setup-cron-job

Feature/setup cron job

Author: hicks8989

package-lock.json

@@ -34,6 +34,7 @@
     "dotenv": "^16.0.2",
     "express": "^4.18.1",
     "mongoose": "^6.6.1",
+    "node-cron": "^3.0.2",
     "winston": "^3.8.2"
   },
   "devDependencies": {
@@ -43,6 +44,7 @@
     "@types/express": "^4.17.14",
     "@types/jest": "^29.0.3",
     "@types/node": "^18.7.18",
+    "@types/node-cron": "^3.0.4",
     "babel-jest": "^29.0.3",
     "jest": "^29.0.3",
     "jest-rest-preset": "^0.0.4",

package.json

@@ -1,4 +1,5 @@
 import mongoose from 'mongoose';
+import { logger } from '../logger';
 
 export class Database {
   private static url : string | undefined;
@@ -7,11 +8,11 @@ export class Database {
     mongoose.connect(this.connectionString);
 
     mongoose.connection.once("open", async () : Promise<void> => {
-      console.log("Connected to database");
+      logger.info("Connected to database");
     });
 
     mongoose.connection.on("error", async (e) : Promise<void> => {
-      console.log("Error connectiong to database", e);
+      logger.error("Error connectiong to database", e);
     });
   }
 
@@ -23,7 +24,7 @@ export class Database {
     mongoose.disconnect();
 
     mongoose.connection.close(async () : Promise<void> => {
-      console.log("Disconnected from database");
+      logger.info("Disconnected from database");
     })
   }
 

src/db/db.config.ts

@@ -4,11 +4,7 @@ import { ProblemExtractor } from '../packages/problem-extractor';
 import { logger } from '../logger';
 
 export class PopulateProblems {
-  private static data : Promise<LeetcodeProblem[] | null> | null = null;
-
-  public static async populate() : Promise<void> {
-    const problems = await this.problems;
-
+  public static async populate(problems : LeetcodeProblem[] | null) : Promise<void> {
     if (problems === null) {
       return;
     }
@@ -62,12 +58,4 @@ export class PopulateProblems {
 
     await p.save();
   }
-
-  public static get problems() : Promise<LeetcodeProblem[] | null> | null {
-    if (this.data === null) {
-      this.data = ProblemExtractor.problems;
-    }
-
-    return this.data;
-  }
 }

src/db/problems.ts

@@ -1,16 +1,16 @@
 import { app } from "./app";
 import { Database } from "./db/db.config";
-import { PopulateProblems } from "./db/problems";
 import { logger } from "./logger";
+import { CronPopulate } from "./packages/cron-populate";
 
 const serve = async () : Promise<void> => {
   const PORT : string | number = process.env.PORT || 3000;
 
   try {
     await Database.connect();
-    await PopulateProblems.populate();
+    CronPopulate.schedule(process.env.CRON_EXPRESSION || "0 * * * *");
   } catch(e) {
-    logger.error("Exception caught populating database: " + e);
+    logger.error("Exception caught scheduling cron job: " + e);
   }
 
   app.listen(PORT, () => {

src/index.ts

@@ -0,0 +1,20 @@
+import cron, { ScheduledTask } from "node-cron";
+import { ProblemExtractor } from "../problem-extractor";
+import { PopulateProblems } from "../../db/problems";
+import { logger } from "../../logger";
+
+export class CronPopulate {
+  public static async schedule(cronExpression: string) : Promise<ScheduledTask> {
+    return cron.schedule(cronExpression, this.run);
+  }
+
+  private static async run() : Promise<void> {
+    try {
+      const problems = await ProblemExtractor.problems;
+      await PopulateProblems.populate(problems);
+      logger.info("Successfully updated database through cron job");
+    } catch(e) {
+      logger.error("Exception caught running cron job: " + e);
+    }
+  }
+}

src/packages/cron-populate/index.ts

@@ -4,28 +4,18 @@ import { axiosClient } from './axios-client';
 import { LeetcodeProblem } from './interfaces';
 
 export class ProblemExtractor {
-  private static parsedData : Promise<LeetcodeProblem[] | null> | null = null;
-
   public static get problems() : Promise<LeetcodeProblem[] | null> | null {
-    if (this.parsedData === null) {
-      this.parsedData = this.makeAPICallAndGetData();
-    }
-
-    return this.parsedData;
+    return this.makeAPICallAndGetData();
   }
 
   private static async makeAPICallAndGetData() : Promise<LeetcodeProblem[] | null> {
-    let data : AxiosResponse;
-
     try {
-      data = await axiosClient.get("/api/problems/all");
+      const data : AxiosResponse = await axiosClient.get("/api/problems/all");
+      const parsedData : LeetcodeProblem[] = data.data.stat_status_pairs;
+      return parsedData;
     } catch(e) {
       logger.error("Exception caught getting data from leetcode API " + e);
       return null;
     }
-
-    const parsedData : LeetcodeProblem[] = data.data.stat_status_pairs;
-
-    return parsedData;
   }
 }