feature: add loggers and save logs to DB when using Firebase

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,
+}