Merge pull request #42 from anzharip/feat/healthcheck

feat: add healthcheck endpoint

README.md

@@ -1,14 +1,16 @@
 # tweet-summary-bot
 
-A twitter bot written in Typescript to check the most frequent words and sentiment analysis by a particular twitter user. Currently focused on English and Bahasa Indonesia. 
+A twitter bot written in Typescript to check the most frequent words and sentiment analysis by a particular twitter user. Currently focused on English and Bahasa Indonesia.
 
-## How it works: 
-1. Reply to a tweet of the user that you want to analyze, and mention the user defined in the `TWITTER_ACCOUNT_TO_LISTEN` environment variable. 
-2. The account set with `TWITTER_API_KEY, TWITTER_API_SECRET_KEY, TWITTER_ACCESS_TOKEN_KEY, TWITTER_ACCESS_TOKEN_SECRET_KEY, TWITTER_BEARER_TOKEN` will reply to the your tweet with the information. 
+## How it works:
+
+1. Reply to a tweet of the user that you want to analyze, and mention the user defined in the `TWITTER_ACCOUNT_TO_LISTEN` environment variable.
+2. The account set with `TWITTER_API_KEY, TWITTER_API_SECRET_KEY, TWITTER_ACCESS_TOKEN_KEY, TWITTER_ACCESS_TOKEN_SECRET_KEY, TWITTER_BEARER_TOKEN` will reply to the your tweet with the information.
 
 ![Screen Shot 2020-11-07 at 10 59 23](https://user-images.githubusercontent.com/10259593/98431468-4cec7b00-20e8-11eb-892d-380bc7a63364.png)
 
 ## Environment Variables
+
 ```bash
 TWITTER_API_KEY=xxx
 TWITTER_API_SECRET_KEY=xxx
@@ -17,14 +19,18 @@ TWITTER_ACCESS_TOKEN_SECRET_KEY=xxx
 TWITTER_BEARER_TOKEN=xxx
 TWITTER_ACCOUNT_TO_LISTEN=@sometwitterhandle
 GOOGLE_API_TRANSLATE_TARGET_LANGUAGE=en
-GOOGLE_APPLICATION_CREDENTIALS=google-application-credentials/credentials.json 
+GOOGLE_APPLICATION_CREDENTIALS=google-application-credentials/credentials.json
+HEALTHCHECK_PORT=3000
 ```
 
-Notes: 
+Notes:
+
 1. More info about `GOOGLE_API_TRANSLATE_TARGET_LANGUAGE`: https://cloud.google.com/translate/docs/languages
 2. More info about `GOOGLE_APPLICATION_CREDENTIALS`: https://cloud.google.com/docs/authentication/getting-started
+3. You can do a periodic healthcheck on this service by hitting the http://0.0.0.0:3000/status endpoint.
 
 ## Running the app
+
 ```
 # development
 $ npm run start:dev

src/index.ts

@@ -4,6 +4,7 @@
 import "dotenv/config";
 import { retrieveQuestion } from "./incoming";
 import { sendAnswer } from "./outgoing";
+import { server } from "./utility/healthcheck";
 import { logger } from "./utility/logger";
 import { queueQuestion, queueSummary } from "./utility/queue";
 import { generateSummary } from "./utility/twitter/tweet-utilities";
@@ -30,6 +31,11 @@ async function app() {
     }
   }, 1000);
 
+  server.listen(Number(process.env.HEALTHCHECK_PORT) || 3000);
+  server.on("listening", () => {
+    logger.info("Healthcheck is up");
+  });
+
   logger.info("Service has been started!");
 }
 

src/utility/healthcheck.ts

@@ -0,0 +1,18 @@
+import { createServer, IncomingMessage, ServerResponse } from "http";
+
+export const server = createServer(
+  (request: IncomingMessage, response: ServerResponse) => {
+    if (request.url === "/status") {
+      if (request.method === "GET") {
+        response.end(
+          JSON.stringify({
+            status: "up",
+          })
+        );
+      }
+    } else {
+      response.statusCode = 404;
+      response.end();
+    }
+  }
+);