add logging

.gitignore

@@ -1,3 +1,4 @@
 height
+history
 node_modules
 package-lock.json

desk-machine.js

@@ -8,6 +8,8 @@ const gpio  = require('rpi-gpio')
 
 const MAX_HEIGHT = 18
 const HEIGHT_FILE  = __dirname + '/height'
+const HISTORY_FILE = __dirname + '/history'
+
 const SPEED = 0.56 // how fast the desk extends/retracts (inches per second)
 
 const gpiop = gpio.promise
@@ -22,6 +24,7 @@ let currentHeight = 0
 
 function saveHeight (height) {
     fs.writeFileSync(HEIGHT_FILE, height, 'utf8')
+    fs.appendFileSync(HISTORY_FILE, `${Date.now()},${height}\n`)
 }
 
 

index.js

@@ -5,6 +5,7 @@
 const delay                  = require('delay')
 const deskMachine            = require('./desk-machine.js')
 const express                = require('express')
+const fs                     = require('fs')
 const register               = require('register-multicast-dns')
 const safeHandler            = require('async-middleware').wrap
 const serveStatic            = require('serve-static')
@@ -24,6 +25,14 @@ app.use(function (req, res, next) {
   return next()
 })
 
+app.get('/history', function (req, res) {
+  if (!fs.existsSync(__dirname + '/history'))
+    return res.send('')
+
+  const history = fs.readFileSync(__dirname + '/history', 'utf8')
+  res.send(history)
+})
+
 app.get('/state', safeHandler(async function (req, res) {
   req.socket.setTimeout(0);
   req.socket.setNoDelay(true);