Add prometheus

Dockerfile

@@ -1,12 +1,12 @@
 FROM node:16.0.0-alpine AS dev-deps
 WORKDIR /opt/build
 COPY package.json package-lock.json ./
-RUN npm ci --no-audit --silent
+RUN npm ci --no-audit
 
 FROM node:16.0.0-alpine AS prod-deps
 WORKDIR /opt/app
 COPY package.json package-lock.json ./
-RUN npm ci --no-audit --only prod --silent
+RUN npm ci --no-audit --only prod
 
 FROM dev-deps AS build
 WORKDIR /opt/build

src/index.ts

@@ -2,6 +2,7 @@ import { Telegraf } from "telegraf";
 import util from "util";
 import * as path from "path";
 import * as crypto from "crypto";
+import { createServer } from "http";
 
 import { Composer } from "./composer";
 import { Ctx } from "./types";
@@ -10,6 +11,7 @@ import { initLogger, log } from "./logger";
 import { noop, regexp } from "./utils";
 import * as middlewares from "./middlewares";
 import * as commands from "./commands";
+import { registerPromHandlers, getRawMetrics } from "./prometheus";
 
 async function main() {
   if (process.env.NODE_ENV === "development") {
@@ -40,6 +42,8 @@ async function main() {
   const username = botInfo.username;
   const composer2 = new Composer();
 
+  registerPromHandlers(bot);
+
   bot
     .use(composer2)
     .use(middlewares.getDbChat)
@@ -196,16 +200,39 @@ async function main() {
       break;
     case "production": {
       log.info("Launching in webhook mode");
-      const { WEBHOOK_PATH, WEBHOOK_DOMAIN, WEBHOOK_PORT, SERVER_PORT } =
+      const { WEBHOOK_DOMAIN, WEBHOOK_PORT, SERVER_PORT, BOT_TOKEN } =
         process.env;
-      await bot.launch({
-        dropPendingUpdates: true,
-        webhook: {
-          hookPath: WEBHOOK_PATH,
-          domain: `${WEBHOOK_DOMAIN}:${WEBHOOK_PORT}`,
-          port: parseInt(SERVER_PORT!),
-        },
+      const proxyPrefix = "/blcklstbot";
+      const webhookCallback = bot.webhookCallback(
+        `${proxyPrefix}/${BOT_TOKEN}`,
+      );
+      await bot.telegram.setWebhook(
+        `https://${WEBHOOK_DOMAIN}:${WEBHOOK_PORT}${proxyPrefix}/${BOT_TOKEN}`,
+        { drop_pending_updates: true },
+      );
+      const server = createServer(async (req, res) => {
+        if (req.url === `${proxyPrefix}/metrics`) {
+          try {
+            const raw = await getRawMetrics();
+            return res
+              .writeHead(200, { "Content-Type": "text/plain" })
+              .end(raw);
+          } catch (err) {
+            return res.writeHead(500).end((err as Error).message);
+          }
+        }
+        return webhookCallback(req, res);
       });
+      server.listen(SERVER_PORT);
+
+      // await bot.launch({
+      //   dropPendingUpdates: true,
+      //   webhook: {
+      //     hookPath: WEBHOOK_PATH,
+      //     domain: `${WEBHOOK_DOMAIN}:${WEBHOOK_PORT}`,
+      //     port: parseInt(SERVER_PORT!),
+      //   },
+      // });
       break;
     }
     default:

src/prometheus.ts

@@ -0,0 +1,31 @@
+import { Counter, register } from "prom-client";
+import type { Telegraf } from "telegraf";
+import type { MessageSubType } from "telegraf/typings/telegram-types";
+import type { Ctx } from "./types";
+
+const promMessageCounter = new Counter({
+  name: "tg_messages_total",
+  help: "Message counter",
+  labelNames: ["media_type"],
+});
+
+const promUpdateTypes: MessageSubType[] = [
+  "text",
+  "photo",
+  "sticker",
+  "photo",
+  "video",
+];
+
+export function registerPromHandlers(bot: Telegraf<Ctx>) {
+  for (const msgSubType of promUpdateTypes) {
+    bot.on(msgSubType, (_ctx, next) => {
+      promMessageCounter.inc({ media_type: msgSubType });
+      return next();
+    });
+  }
+}
+
+export function getRawMetrics() {
+  return register.metrics();
+}