From c55774eb391a2e07771ce40fec35e912c9a8b2fe Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ond=C5=99ej=20Syn=C3=A1=C4=8Dek?=
 <ondrejsynacek@fastmail.com>
Date: Sun, 15 Nov 2020 21:33:16 +0100
Subject: [PATCH] feature: add loggers and save logs to DB when using Firebase

---
 database.rules.json    |  6 ++++
 firebase.json          |  3 ++
 functions/index.js     | 21 ++++++++-----
 functions/logger.js    | 68 ++++++++++++++++++++++++++++++++++++++++++
 functions/package.json | 11 +++----
 5 files changed, 96 insertions(+), 13 deletions(-)
 create mode 100644 database.rules.json
 create mode 100644 functions/logger.js

diff --git a/database.rules.json b/database.rules.json
new file mode 100644
index 0000000..c0aa595
--- /dev/null
+++ b/database.rules.json
@@ -0,0 +1,6 @@
+{
+  "rules": {
+    ".read": "auth != null",
+    ".write": "auth != null"
+  }
+}
\ No newline at end of file
diff --git a/firebase.json b/firebase.json
index 15d17eb..348508d 100644
--- a/firebase.json
+++ b/firebase.json
@@ -21,5 +21,8 @@
         "function": "app"
       }
     ]
+  },
+  "database": {
+    "rules": "database.rules.json"
   }
 }
diff --git a/functions/index.js b/functions/index.js
index 3b1c1ac..039e5f2 100644
--- a/functions/index.js
+++ b/functions/index.js
@@ -2,19 +2,21 @@ const functions = require('firebase-functions');
 const admin = require('firebase-admin')
 
 const { configureApplication } = require('./lib/app')
-// const { createAppLogger } = require('./lib/log-utils')
-// const {
-//   createRouteLogger,
-//   createErrorLogger,
-// } = require('./lib/middlewares')
+const {
+  createRouteLogger,
+  createErrorLogger,
+  createAppLogger,
+} = require('./logger')
 
 admin.initializeApp()
 
 const isDevelopment = process.env.NODE_ENV === 'development'
 
-// const appLogger = createAppLogger({ dev: isDevelopment })
-// const errorLogger = createErrorLogger({ dev: isDevelopment })
-// const routeLogger = isDevelopment ? createRouteLogger({ dev: isDevelopment }) : null
+const db = admin.database()
+
+const appLogger = createAppLogger({ db })
+const errorLogger = createErrorLogger({ db })
+const routeLogger = createRouteLogger({ db })
 const corsOptions = isDevelopment ? {
   origin: 'http://localhost:5000',
 } : null
@@ -22,6 +24,9 @@ const corsOptions = isDevelopment ? {
 const app = configureApplication({
   rateLimitEnabled: false,
   corsOptions,
+  appLogger,
+  errorLogger,
+  routeLogger,
 })
 
 exports.app = functions.https.onRequest(app)
diff --git a/functions/logger.js b/functions/logger.js
new file mode 100644
index 0000000..db59880
--- /dev/null
+++ b/functions/logger.js
@@ -0,0 +1,68 @@
+const winston = require('winston')
+const expressWinston = require('express-winston')
+const Transport = require('winston-transport')
+
+class FirebaseTransport extends Transport {
+  constructor(options) {
+    super(options)
+    this._db = options.db
+  }
+
+  log(info, callback) {
+    try {
+      this._db.ref(`log-${new Date().getTime()}`).set(info)
+      callback(null, info)
+      this.emit('logged', info)
+    } catch (err) {
+      callback(error)
+      this.emit('error', error)
+    }
+
+    return info
+  }
+}
+
+const createRouteLogger = (db) => {
+  return expressWinston.logger({
+    transports: [
+      new FirebaseTransport({ db })
+    ],
+    format: winston.format.combine(
+      winston.format.timestamp(),
+      winston.format.json()
+    ),
+    meta: true,
+    expressFormat: true,
+  })
+}
+
+const createErrorLogger = ({ db }) => {
+  return expressWinston.errorLogger({
+    transports: [
+      new FirebaseTransport({ db })
+    ],
+    format: winston.format.combine(
+      winston.format.timestamp(),
+      winston.format.json()
+    ),
+  })
+}
+
+const createAppLogger = ({ db }) => {
+  return winston.createLogger({
+    format: winston.format.combine(
+      winston.format.timestamp(),
+      winston.format.json()
+    ),
+    transports: [
+      new FirebaseTransport({ db }),
+      new winston.transports.Console(),
+    ]
+  })
+}
+
+module.exports = {
+  createRouteLogger,
+  createErrorLogger,
+  createAppLogger,
+}
diff --git a/functions/package.json b/functions/package.json
index 5fbb77e..a2f682c 100644
--- a/functions/package.json
+++ b/functions/package.json
@@ -13,8 +13,6 @@
   },
   "main": "index.js",
   "dependencies": {
-    "firebase-admin": "^9.2.0",
-    "firebase-functions": "^3.11.0",
     "body-parser": "^1.19.0",
     "cheerio": "^1.0.0-rc.3",
     "cors": "^2.8.5",
@@ -22,12 +20,15 @@
     "ejs": "^2.7.1",
     "express": "^4.17.1",
     "express-rate-limit": "^5.0.0",
-    "express-winston": "^4.0.1",
+    "express-winston": "^4.0.5",
+    "firebase-admin": "^9.2.0",
+    "firebase-functions": "^3.11.0",
     "ics": "^2.22.1",
     "request": "^2.88.0",
     "serve-favicon": "^2.5.0",
-    "winston": "^3.2.1",
-    "winston-daily-rotate-file": "^4.2.1"
+    "winston": "^3.3.3",
+    "winston-daily-rotate-file": "^4.2.1",
+    "winston-transport": "^4.4.0"
   },
   "devDependencies": {
     "firebase-functions-test": "^0.2.0"