initial commit or smth

.gitignore

@@ -6,4 +6,5 @@ dist/
 .vscode
 *.log
 *.tsbuildinfo
-.env
+.env
+keywords.yml

README.md

@@ -1,6 +1,49 @@
 # mtproto_exporter
 
-mtcute powered Telegram bot
+mtcute powered Prometheus metrics exporter
+
+*this exporter is mostly useful only with userbot*
+
+## Available Metrics
+`messenger_dialog_info{peerId, peerType, displayName}`
+
+Dialog information exposed as labels
+
+`messenger_dialog_messages_count{peerId}`
+
+Messages count since exporter startup
+
+`messenger_dialog_unread_messages_count{peerId}`
+
+Number of unread messages in dialogs
+
+`messenger_dialog_keywords_count{peerId}`
+
+Number of keywords found in messages since exporter startup
+
+`messenger_dialog_words_count{peerId}`
+
+Number of words in messages since exporter startup
+
+This metric is disabled by default because it will produce a lot of unique time series (more info [here](https://prometheus.io/docs/practices/naming/#labels))
+
+This will expose each **word** in each **message** in each **chat** as unique metric.
+
+This metric can be enabled with command line flag `--words-counter`
+
+## CLI Options
+`--bind-host`, `-b` - ip address where http server will be listening on
+
+`--port`, `-p` - port where http server will be listening on
+
+`--words-counter` - enable each word counting metric
+
+`--keywords-file`, `-k` - path to yaml file with keywords and patterns (see [keywords.yml.example](./keywords.yml.example))
+
+## Environment Variables
+
+`API_ID` - Telegram api id used for mtproto connection (see [mtcute.dev](https://mtcute.dev/guide/intro/sign-in.html))
+`API_HASH` - Telegram api hash used for mtproto connection (see [mtcute.dev](https://mtcute.dev/guide/intro/sign-in.html))
 
 ## Development
 

eslint.config.js

@@ -1,19 +1,20 @@
-import antfu from '@antfu/eslint-config'
+import antfu from "@antfu/eslint-config";
 
 export default antfu({
     stylistic: {
         indent: 4,
+        semi: true,
+        quotes: "double",
     },
     typescript: true,
     yaml: false,
     rules: {
-        'curly': ['error', 'multi-line'],
+        "curly": ["error", "multi-line"],
-        'style/brace-style': ['error', '1tbs', { allowSingleLine: true }],
+        "style/brace-style": ["error", "1tbs", { allowSingleLine: true }],
-        'style/quotes': ['error', 'single', { avoidEscape: true }],
+        // "import/order": ["error", { "newlines-between": "always" }], this shit breaks eslint
-        'import/order': ['error', { 'newlines-between': 'always' }],
+        "antfu/if-newline": "off",
-        'antfu/if-newline': 'off',
+        "style/max-statements-per-line": ["error", { max: 2 }],
-        'style/max-statements-per-line': ['error', { max: 2 }],
+        "no-console": "off",
-        'no-console': 'off',
+        "antfu/no-top-level-await": "off",
-        'antfu/no-top-level-await': 'off',
     },
-})
+});

keywords.yml.example

@@ -0,0 +1,4 @@
+keywords:
+    - meow
+    - name: woof
+      pattern: 'w[oa]+f'

package.json

@@ -7,16 +7,21 @@
     "scripts": {
         "lint": "eslint .",
         "lint:fix": "eslint --fix .",
-        "start": "dotenv tsx ./src/main.ts",
+        "start": "dotenv tsx ./src/main.ts --",
         "build": "tsc"
     },
     "dependencies": {
         "@mtcute/dispatcher": "^0.22.2",
         "@mtcute/node": "^0.22.3",
-        "dotenv-cli": "^8.0.0"
+        "command-line-args": "^6.0.1",
+        "dotenv-cli": "^8.0.0",
+        "js-yaml": "^4.1.0",
+        "prom-client": "^15.1.3"
     },
     "devDependencies": {
         "@antfu/eslint-config": "^4.11.0",
+        "@types/command-line-args": "^5.2.3",
+        "@types/js-yaml": "^4.0.9",
         "@types/node": "^22.14.0",
         "tsx": "^4.19.3",
         "typescript": "^5.8.3"

pnpm-lock.yaml

@@ -14,9 +14,24 @@ importers:
       '@mtcute/node':
         specifier: ^0.22.3
         version: 0.22.3
+      '@types/command-line-args':
+        specifier: ^5.2.3
+        version: 5.2.3
+      '@types/js-yaml':
+        specifier: ^4.0.9
+        version: 4.0.9
+      command-line-args:
+        specifier: ^6.0.1
+        version: 6.0.1
       dotenv-cli:
         specifier: ^8.0.0
         version: 8.0.0
+      js-yaml:
+        specifier: ^4.1.0
+        version: 4.1.0
+      prom-client:
+        specifier: ^15.1.3
+        version: 15.1.3
     devDependencies:
       '@antfu/eslint-config':
         specifier: ^4.11.0
@@ -421,6 +436,10 @@ packages:
     resolution: {integrity: sha512-oGB+UxlgWcgQkgwo8GcEGwemoTFt3FIO9ababBmaGwXIoBKZ+GTy0pP185beGg7Llih/NSHSV2XAs1lnznocSg==}
     engines: {node: '>= 8'}
 
+  '@opentelemetry/api@1.9.0':
+    resolution: {integrity: sha512-3giAOQvZiH5F9bMlMiv8+GSPMeqg0dbaeo58/0SlA9sxSqZhnUtxzX9/2FzyhS9sWQf5S0GJE0AKBrFqjpeYcg==}
+    engines: {node: '>=8.0.0'}
+
   '@pkgr/core@0.1.2':
     resolution: {integrity: sha512-fdDH1LSGfZdTH2sxdpVMw31BanV28K/Gry0cVFxaNP77neJSkd82mM8ErPNYs9e+0O7SdHBLTDzDgwUuy18RnQ==}
     engines: {node: ^12.20.0 || ^14.18.0 || >=16.0.0}
@@ -438,6 +457,9 @@ packages:
   '@tybys/wasm-util@0.9.0':
     resolution: {integrity: sha512-6+7nlbMVX/PVDCwaIQ8nTOPveOcFLSt8GcXdx8hD0bt39uWxYT88uXzqTd4fTvqta7oeUJqudepapKNt2DYJFw==}
 
+  '@types/command-line-args@5.2.3':
+    resolution: {integrity: sha512-uv0aG6R0Y8WHZLTamZwtfsDLVRnOa+n+n5rEvFWL5Na5gZ8V2Teab/duDPFzIIIhs9qizDpcavCusCLJZu62Kw==}
+
   '@types/debug@4.1.12':
     resolution: {integrity: sha512-vIChWdVG3LG1SMxEvI/AK+FWJthlrqlTu7fbrlywTkkaONwk/UAGaULXRlf8vkzFBLVm0zkMdCquhL5aOjhXPQ==}
 
@@ -453,6 +475,9 @@ packages:
   '@types/events@3.0.0':
     resolution: {integrity: sha512-EaObqwIvayI5a8dCzhFrjKzVwKLxjoG9T6Ppd5CEo07LRKfQ8Yokw54r5+Wq7FaBQ+yXRvQAYPrHwya1/UFt9g==}
 
+  '@types/js-yaml@4.0.9':
+    resolution: {integrity: sha512-k4MGaQl5TGo/iipqb2UDG2UwjXziSWkh0uysQelTlJpX1qGlpUZYm8PnO4DxG1qBomtJUdYJ6qR6xdIah10JLg==}
+
   '@types/json-schema@7.0.15':
     resolution: {integrity: sha512-5+fP8P8MFNC+AyZCDxrB2pkZFPGzqQWUzpSeuuVLvm8VMcorNYavBqoFcxK8bQz4Qsbn4oUEEem4wDLfcysGHA==}
 
@@ -649,6 +674,10 @@ packages:
   argparse@2.0.1:
     resolution: {integrity: sha512-8+9WqebbFzpX9OR+Wa6O29asIogeRMzcGtAINdpMHHyAg10f05aSFVBbcEqGf/PXw1EjAZ+q2/bEBg3DvurK3Q==}
 
+  array-back@6.2.2:
+    resolution: {integrity: sha512-gUAZ7HPyb4SJczXAMUXMGAvI976JoK3qEx9v1FTmeYuJj0IBiaKttG1ydtGKdkfqWkIkouke7nG8ufGy77+Cvw==}
+    engines: {node: '>=12.17'}
+
   balanced-match@1.0.2:
     resolution: {integrity: sha512-3oSeUO0TMV67hN1AmbXsK4yaqU7tjiHlbxRDZOpH0KW9+CeX4bRAaX0Anxt0tx2MrpRpWwQaPwIlISEJhYU5Pw==}
 
@@ -661,6 +690,9 @@ packages:
   bindings@1.5.0:
     resolution: {integrity: sha512-p2q/t/mhvuOj/UeLlV6566GD/guowlr0hHxClI0W9m7MWYkL1F0hLo+0Aexs9HSPCtR1SXQ0TD3MMKrXZajbiQ==}
 
+  bintrees@1.0.2:
+    resolution: {integrity: sha512-VOMgTMwjAaUG580SXn3LacVgjurrbMme7ZZNYGSSV7mmtY6QQRh0Eg3pwIcntQ77DErK1L0NxkbetjcoXzVwKw==}
+
   bl@4.1.0:
     resolution: {integrity: sha512-1W07cM9gS6DcLperZfFSj+bWLtaPGSOHWhPiGzXmvVJbRLdG82sH/Kn8EtW1VqWVA54AKf2h5k5BbnIbwF3h6w==}
 
@@ -728,6 +760,15 @@ packages:
   color-name@1.1.4:
     resolution: {integrity: sha512-dOy+3AuW3a2wNbZHIuMZpTcgjGuLU/uBL/ubcZF9OXbDo8ff4O8yVp5Bf0efS8uEoYo5q4Fx7dY9OgQGXgAsQA==}
 
+  command-line-args@6.0.1:
+    resolution: {integrity: sha512-Jr3eByUjqyK0qd8W0SGFW1nZwqCaNCtbXjRo2cRJC1OYxWl3MZ5t1US3jq+cO4sPavqgw4l9BMGX0CBe+trepg==}
+    engines: {node: '>=12.20'}
+    peerDependencies:
+      '@75lb/nature': latest
+    peerDependenciesMeta:
+      '@75lb/nature':
+        optional: true
+
   comment-parser@1.4.1:
     resolution: {integrity: sha512-buhp5kePrmda3vhc5B9t7pUQXAb2Tnd0qgpkIhPhkHXxJpiPJ11H0ZEU0oBpJ2QztSbzG/ZxMj/CHsYJqRHmyg==}
     engines: {node: '>= 12.0.0'}
@@ -1097,6 +1138,15 @@ packages:
     resolution: {integrity: sha512-YsGpe3WHLK8ZYi4tWDg2Jy3ebRz2rXowDxnld4bkQB00cc/1Zw9AWnC0i9ztDJitivtQvaI9KaLyKrc+hBW0yg==}
     engines: {node: '>=8'}
 
+  find-replace@5.0.2:
+    resolution: {integrity: sha512-Y45BAiE3mz2QsrN2fb5QEtO4qb44NcS7en/0y9PEVsg351HsLeVclP8QPMH79Le9sH3rs5RSwJu99W0WPZO43Q==}
+    engines: {node: '>=14'}
+    peerDependencies:
+      '@75lb/nature': latest
+    peerDependenciesMeta:
+      '@75lb/nature':
+        optional: true
+
   find-up-simple@1.0.1:
     resolution: {integrity: sha512-afd4O7zpqHeRyg4PfDQsXmlDe2PfdHtJt6Akt8jOWaApLOZk5JXs6VMR29lz03pRe9mpykrRCYIYxaJYcfpncQ==}
     engines: {node: '>=18'}
@@ -1271,6 +1321,9 @@ packages:
     resolution: {integrity: sha512-iPZK6eYjbxRu3uB4/WZ3EsEIMJFMqAoopl3R+zuq0UjcAm/MO6KCweDgPfP3elTztoKP3KtnVHxTn2NHBSDVUw==}
     engines: {node: '>=10'}
 
+  lodash.camelcase@4.3.0:
+    resolution: {integrity: sha512-TwuEnCnxbc3rAvhf/LbG7tJUDzhqXyFnv3dtzLOPgCG/hODL7WFnsbwktkD7yUV0RrreP/l1PALq/YSg6VvjlA==}
+
   lodash.merge@4.6.2:
     resolution: {integrity: sha512-0KpjqXRVvrYyCsX1swR/XTK0va6VQkQM6MNo7PqW77ByjAhoARA8EfrP1N4+KlKj8YS0ZUCtRT/YUuhyYDujIQ==}
 
@@ -1566,6 +1619,10 @@ packages:
     resolution: {integrity: sha512-vkcDPrRZo1QZLbn5RLGPpg/WmIQ65qoWWhcGKf/b5eplkkarX0m9z8ppCat4mlOqUsWpyNuYgO3VRyrYHSzX5g==}
     engines: {node: '>= 0.8.0'}
 
+  prom-client@15.1.3:
+    resolution: {integrity: sha512-6ZiOBfCywsD4k1BN9IX0uZhF+tJkV8q8llP64G5Hajs4JOeVLPCwpPVcpXy3BwYiUGgyJzsJJQeOIv7+hDSq8g==}
+    engines: {node: ^16 || ^18 || >=20}
+
   pump@3.0.2:
     resolution: {integrity: sha512-tUPXtzlGM8FE3P0ZL6DVs/3P58k9nk8/jZeQCurTJylQA8qFYzHFfhBJkuqyE0FifOsQ0uKWekiZ5g8wtr28cw==}
 
@@ -1726,6 +1783,9 @@ packages:
     resolution: {integrity: sha512-ujeqbceABgwMZxEJnk2HDY2DlnUZ+9oEcb1KzTVfYHio0UE6dG71n60d8D2I4qNvleWrrXpmjpt7vZeF1LnMZQ==}
     engines: {node: '>=6'}
 
+  tdigest@0.1.2:
+    resolution: {integrity: sha512-+G0LLgjjo9BZX2MfdvPfH+MKLCrxlXSYec5DaPYP1fe6Iyhf0/fSmJ0bFiZ1F8BT6cGXl2LpltQptzjXKWEkKA==}
+
   tinyexec@0.3.2:
     resolution: {integrity: sha512-KQQR9yN7R5+OSwaK0XQoj22pwHoTlgYqmUscPYoknOoWCWfj/5/ABTMRi69FrKU5ffPVh5QcFikpWJI/P1ocHA==}
 
@@ -1771,6 +1831,10 @@ packages:
     engines: {node: '>=14.17'}
     hasBin: true
 
+  typical@7.3.0:
+    resolution: {integrity: sha512-ya4mg/30vm+DOWfBg4YK3j2WD6TWtRkCbasOJr40CseYENzCUby/7rIvXA99JGsQHeNxLbnXdyLLxKSv3tauFw==}
+    engines: {node: '>=12.17'}
+
   ufo@1.5.4:
     resolution: {integrity: sha512-UsUk3byDzKd04EyoZ7U4DOlxQaD14JUKQl6/P7wiX4FNvUfm3XL246n9W5AmqwW5RSFJ27NAuM0iLscAOYUiGQ==}
 
@@ -2217,6 +2281,8 @@ snapshots:
       '@nodelib/fs.scandir': 2.1.5
       fastq: 1.19.1
 
+  '@opentelemetry/api@1.9.0': {}
+
   '@pkgr/core@0.1.2': {}
 
   '@pkgr/core@0.2.0': {}
@@ -2238,6 +2304,8 @@ snapshots:
       tslib: 2.8.1
     optional: true
 
+  '@types/command-line-args@5.2.3': {}
+
   '@types/debug@4.1.12':
     dependencies:
       '@types/ms': 2.1.0
@@ -2253,6 +2321,8 @@ snapshots:
 
   '@types/events@3.0.0': {}
 
+  '@types/js-yaml@4.0.9': {}
+
   '@types/json-schema@7.0.15': {}
 
   '@types/mdast@4.0.4':
@@ -2455,6 +2525,8 @@ snapshots:
 
   argparse@2.0.1: {}
 
+  array-back@6.2.2: {}
+
   balanced-match@1.0.2: {}
 
   base64-js@1.5.1: {}
@@ -2468,6 +2540,8 @@ snapshots:
     dependencies:
       file-uri-to-path: 1.0.0
 
+  bintrees@1.0.2: {}
+
   bl@4.1.0:
     dependencies:
       buffer: 5.7.1
@@ -2532,6 +2606,13 @@ snapshots:
 
   color-name@1.1.4: {}
 
+  command-line-args@6.0.1:
+    dependencies:
+      array-back: 6.2.2
+      find-replace: 5.0.2
+      lodash.camelcase: 4.3.0
+      typical: 7.3.0
+
   comment-parser@1.4.1: {}
 
   concat-map@0.0.1: {}
@@ -2989,6 +3070,8 @@ snapshots:
     dependencies:
       to-regex-range: 5.0.1
 
+  find-replace@5.0.2: {}
+
   find-up-simple@1.0.1: {}
 
   find-up@5.0.0:
@@ -3132,6 +3215,8 @@ snapshots:
     dependencies:
       p-locate: 5.0.0
 
+  lodash.camelcase@4.3.0: {}
+
   lodash.merge@4.6.2: {}
 
   lodash@4.17.21: {}
@@ -3603,6 +3688,11 @@ snapshots:
 
   prelude-ls@1.2.1: {}
 
+  prom-client@15.1.3:
+    dependencies:
+      '@opentelemetry/api': 1.9.0
+      tdigest: 0.1.2
+
   pump@3.0.2:
     dependencies:
       end-of-stream: 1.4.4
@@ -3768,6 +3858,10 @@ snapshots:
       inherits: 2.0.4
       readable-stream: 3.6.2
 
+  tdigest@0.1.2:
+    dependencies:
+      bintrees: 1.0.2
+
   tinyexec@0.3.2: {}
 
   tinyglobby@0.2.12:
@@ -3808,6 +3902,8 @@ snapshots:
 
   typescript@5.8.3: {}
 
+  typical@7.3.0: {}
+
   ufo@1.5.4: {}
 
   undici-types@6.21.0: {}

src/env.ts

@@ -1,10 +1,10 @@
-import process from 'node:process'
+import process from "node:process";
 
-const API_ID = Number.parseInt(process.env.API_ID!)
+const API_ID = Number.parseInt(process.env.API_ID!);
-const API_HASH = process.env.API_HASH!
+const API_HASH = process.env.API_HASH!;
 
 if (Number.isNaN(API_ID) || !API_HASH) {
-    throw new Error('API_ID or API_HASH not set!')
+    throw new Error("API_ID or API_HASH not set!");
 }
 
-export { API_HASH, API_ID }
+export { API_HASH, API_ID };

src/keywords.ts

@@ -0,0 +1,61 @@
+import type { Dispatcher } from "@mtcute/dispatcher";
+import { PropagationAction } from "@mtcute/dispatcher";
+import { Counter } from "prom-client";
+
+interface KeywordPattern {
+    name: string;
+    pattern: RegExp;
+}
+
+export type KeywordLike = string | KeywordPattern;
+
+export function newWordsCounter(dp: Dispatcher) {
+    const counter = new Counter({
+        name: "messenger_dialog_words_count",
+        help: "Number of words in messages since exporter startup",
+        labelNames: ["peerId", "word"],
+    });
+    dp.onNewMessage(async (msg) => {
+        const words = msg.text.toLowerCase().split(" ");
+        for (const w of words) {
+            counter.inc({
+                peerId: msg.chat.id,
+                word: w,
+            });
+        }
+        return PropagationAction.Continue;
+    });
+    return counter;
+}
+
+export function newKeywordsCounter(dp: Dispatcher, keywords: KeywordLike[]) {
+    const counter = new Counter({
+        name: "messenger_dialog_keywords_count",
+        help: "Number of keywords found in messages since exporter startup",
+        labelNames: ["peerId", "keyword"],
+    });
+    dp.onNewMessage(async (msg) => {
+        for (const kw of keywords) {
+            let count;
+            let kwname;
+            if (typeof kw === "string") {
+                const words = msg.text.toLowerCase().split(" ");
+                count = words.filter(w => w === kw).length;
+                kwname = kw;
+            } else {
+                count = (msg.text.match(kw.pattern) || []).length;
+                kwname = kw.name;
+            }
+            if (count === 0) {
+                continue;
+            }
+            counter.inc({
+                peerId: msg.chat.id,
+                keyword: kwname,
+            }, count);
+        }
+        return PropagationAction.Continue;
+    });
+
+    return counter;
+}

src/main.ts

@@ -1,19 +1,74 @@
-import { Dispatcher, filters } from '@mtcute/dispatcher'
+import type { OptionDefinition } from "command-line-args";
-import { TelegramClient } from '@mtcute/node'
+import type { KeywordLike } from "./keywords.js";
+import fs from "node:fs";
+import { Dispatcher } from "@mtcute/dispatcher";
+import { TelegramClient } from "@mtcute/node";
+import cmdline from "command-line-args";
+import yaml from "js-yaml";
+import { collectDefaultMetrics, Registry } from "prom-client";
 
-import * as env from './env.js'
+import * as env from "./env.js";
+import * as metrics from "./metrics.js";
+import MetricsServer from "./server.js";
+
+const optionDefinitions: OptionDefinition[] = [
+    { name: "bind-host", alias: "b", type: String, defaultValue: "0.0.0.0" },
+    { name: "port", alias: "p", type: Number, defaultValue: 9669 },
+    { name: "words-counter", type: Boolean, defaultValue: false },
+    { name: "keywords-file", alias: "k", type: String },
+];
+
+const cli = cmdline(optionDefinitions);
+
+const keywords: KeywordLike[] = [];
+if (cli["keywords-file"]) {
+    if (!fs.existsSync(cli["keywords-file"])) {
+        throw new Error("--keywords-file set, but file does not exist.");
+    }
+    const doc = yaml.load(fs.readFileSync(cli["keywords-file"], "utf8")) as { keywords?: any[] };
+
+    if (doc.keywords && doc.keywords.constructor.name === "Array") {
+        for (const item of doc.keywords) {
+            if (typeof item === "string") {
+                keywords.push(item);
+            } else if (typeof item === "object" && item.name && item.pattern) {
+                keywords.push({
+                    name: item.name,
+                    pattern: new RegExp(item.pattern, "gi"),
+                });
+            }
+        }
+    } else {
+        throw new Error("Keywords file format error: no 'keywords' property, or not an array.");
+    }
+}
+
+const registry = new Registry();
+
+collectDefaultMetrics({ register: registry });
+
+const server = new MetricsServer(registry);
+server.listen(cli["bind-host"], cli.port);
 
 const tg = new TelegramClient({
     apiId: env.API_ID,
     apiHash: env.API_HASH,
-    storage: 'bot-data/session',
+    storage: "bot-data/session",
-})
+});
 
-const dp = Dispatcher.for(tg)
+const dp = Dispatcher.for(tg);
 
-dp.onNewMessage(filters.start, async (msg) => {
+registry.registerMetric(metrics.newStaticPeerInfoGauge(tg));
-    await msg.answerText('Hello, world!')
+registry.registerMetric(metrics.newUnreadCountGauge(tg));
-})
+registry.registerMetric(metrics.newMessagesCounter(dp));
 
-const user = await tg.start()
+if (keywords.length > 0) {
-console.log('Logged in as', user.username)
+    registry.registerMetric(metrics.newKeywordsCounter(dp, keywords));
+}
+
+if (cli["words-counter"]) {
+    registry.registerMetric(metrics.newWordsCounter(dp));
+}
+
+const user = await tg.start();
+console.log("Logged in as", user.username);

src/metrics.ts

@@ -0,0 +1,63 @@
+import type { Dispatcher } from "@mtcute/dispatcher";
+import type { TelegramClient } from "@mtcute/node";
+import { PropagationAction } from "@mtcute/dispatcher";
+import { Counter, Gauge } from "prom-client";
+
+import { newKeywordsCounter, newWordsCounter } from "./keywords.js";
+
+function newMessagesCounter(dp: Dispatcher) {
+    const counter = new Counter({
+        name: "messenger_dialog_messages_count",
+        help: "Messages count since exporter startup",
+        labelNames: ["peerId"],
+    });
+    dp.onNewMessage(async (msg) => {
+        counter.inc({
+            peerId: msg.chat.id,
+        });
+        return PropagationAction.Continue;
+    });
+    return counter;
+}
+
+function newStaticPeerInfoGauge(tg: TelegramClient) {
+    const gauge = new Gauge({
+        name: "messenger_dialog_info",
+        help: "Dialog information exposed as labels",
+        labelNames: ["peerId", "peerType", "displayName"],
+        collect: async () => {
+            for await (const d of tg.iterDialogs()) {
+                gauge.set({
+                    peerId: d.peer.id,
+                    peerType: d.peer.type,
+                    displayName: d.peer.displayName,
+                }, 1);
+            }
+        },
+    });
+    return gauge;
+}
+
+function newUnreadCountGauge(tg: TelegramClient) {
+    const gauge = new Gauge({
+        name: "messenger_dialog_unread_messages_count",
+        help: "Number of unread messages in dialogs",
+        labelNames: ["peerId"],
+        collect: async () => {
+            for await (const d of tg.iterDialogs()) {
+                gauge.set({
+                    peerId: d.peer.id,
+                }, d.unreadCount);
+            }
+        },
+    });
+    return gauge;
+}
+
+export {
+    newKeywordsCounter,
+    newMessagesCounter,
+    newStaticPeerInfoGauge,
+    newUnreadCountGauge,
+    newWordsCounter,
+};

src/server.ts

@@ -0,0 +1,51 @@
+import type { Registry } from "prom-client";
+import http from "node:http";
+
+export default class MetricsServer {
+    private _registry: Registry;
+    private _httpServer?: http.Server;
+
+    public constructor(registry: Registry) {
+        this._registry = registry;
+    }
+
+    public get registry() {
+        return this._registry;
+    }
+
+    public listen(address: string, port: number) {
+        if (this._httpServer) {
+            throw new Error("This server is already listening");
+        }
+        this._httpServer = http.createServer(this._requestHandler.bind(this));
+        this._httpServer.listen(port, address);
+        console.log(`HTTP Metrics Server is listening on ${address}:${port}`);
+    }
+
+    private async _requestHandler(req: http.IncomingMessage, res: http.ServerResponse) {
+        const url = new URL(`http://${req.headers.host ?? "localhost"}${req.url}`);
+        console.log(`[HTTP] ${req.method} - ${url.href} from ${req.socket.remoteAddress}:${req.socket.remotePort}`);
+
+        if (req.method === "GET" && url.pathname === "/metrics") {
+            try {
+                const metrics = await this._registry.metrics();
+                res.statusCode = 200;
+                res.setHeader("Content-Type", this._registry.contentType);
+                res.write(metrics);
+            } catch (e) {
+                console.error("Metrics collection failed:", e);
+                res.statusCode = 500;
+                res.setHeader("Content-Type", "application/json; charset=utf-8;");
+                res.write("{ \"error\":{\"message\":\"failed to collect metrics.\"}}");
+            }
+            return res.end();
+        }
+
+        if (!res.writableEnded) {
+            res.statusCode = 404;
+            res.setHeader("Content-Type", "application/json; charset=utf-8;");
+            res.write("{\"error\":{\"message\":\"not found.\"}}");
+            return res.end();
+        }
+    }
+}