balena electronjs

electronJS-based resin application template

balena-io-experimental
346
115
JavaScript

This project is deprecated and replaced by balena-electron-env

Balena Electronjs

a boilerplate for developing kiosks, digital signage or other human-machine interaction projects based on ElectronJS and balena

Warning regarding armv6

This project does not currently support the armv6 architecture (ie Raspberry Pi 0 and 1) due to electron limitations. If the issue is fixed on the electron side, we will include it in this project. More on this here

Getting started

  • Sign up on balena
  • go through the getting started guide and create a new application
  • install the balena-cli on your computer
  • clone or download this repository to your local workspace
  • balena push <applicationName>
  • see the magic happening, your device is getting updated Over-The-Air!

Configure via environment variables

Variable Name Value Description Device-specific
RESIN_HOST_CONFIG_gpu_mem a value from 64 to 396 the amount of RAM dedicated to the GPU Raspberry Pi (all revs)

Apply the above settings in the “Fleet Configuration” panel (if applying it for the all devices withing your application), or “Device Configuration” panel (if applying it for a single device).

WHY THIS TEMPLATE

Achieving kinda-smooth desktop application display on devices like the raspberrypi is hard. This project aims to provide a quickstart template.

URL LAUNCHER config via ENV VARS

!!! Please note that since 0.1.0 the bool-based env vars dropped true / false strings in favour of 0 / 1 ones. !!!

simply set these environment varables in your app via “Environment Variables” panel in the balena dashboard to configure the behaviour of your devices.

Please note that the bool type definition in the table is meant to accept to either 0 or 1 values.

  • URL_LAUNCHER_URL string - the URL to be loaded. use file:////usr/src/app/data/index.html to load a local electronJS (or any website) app - defaults to file:////usr/src/app/data/index.html
  • URL_LAUNCHER_NODE bool (converted from string) - whether or not enable nodejs - defaults to 0
  • URL_LAUNCHER_KIOSK bool (converted from string) - whether or not enter KIOSK mode - defaults to 1
  • URL_LAUNCHER_TITLE string - the title of the window. Seen only with URL_LAUNCHER_FRAME=true - defaults to RESIN.IO
  • URL_LAUNCHER_FRAME bool (converted from string) - set to “true” to display the window frame. Seen only with URL_LAUNCHER_KIOSK=false - defaults to 0
  • URL_LAUNCHER_CONSOLE bool (converted from string) - set to “true” to display the debug console - defaults to 0
  • URL_LAUNCHER_WIDTH int (converted from string) - - defaults to 1920
  • URL_LAUNCHER_HEIGHT int (converted from string) - - defaults to 1080
  • URL_LAUNCHER_TOUCH bool (converted from string) - enables touch events if your device supports them - defaults to 0
  • URL_LAUNCHER_TOUCH_SIMULATE bool (converted from string) - simulates touch events - might be useful for touchscreen with partial driver support - be aware this could be a performance hog - defaults to 0
  • URL_LAUNCHER_ZOOM float (converted from string) - The default zoom factor of the page, 3.0 represents 300% - defaults to 1.0
  • URL_LAUNCHER_OVERLAY_SCROLLBARS bool (converted from string) - enables overlay scrollbars - defaults to 0
  • TFT bool (converted from string) - sets the target display to TFT screen like the piTFT but still requires you to set the proper device tree overlay configuration for it - defaults to 0
  • TFT_ROTATE int (converted from string) - accepted values: 0,90,180,270 - defaults to 0
  • ELECTRON_ENABLE_HW_ACCELERATION bool (converted from string) - enable hardware acceleration - defaults to 0
  • ELECTRON_BALENA_UPDATE_LOCK bool (converted from string) - Enable supervisor update locking (see Update Locking)
  • ELECTRON_APP_DATA_DIR string - Override the appData directory (see Electron API Documentation: app)
  • ELECTRON_USER_DATA_DIR string - Override the userData directory (see Electron API Documentation: app)

Update Locking

NOTE: Take care to only listen for a response once, and avoid sending
multiple requests before the response arrived.

const {ipcRenderer} = require('electron')

Acquiring the Lock

// Listen for a response
ipcRenderer.once('balena-update-lock', (event, error) => {
  if (error) { ... }
})

// Send the 'lock' command to acquire the lock
ipcRenderer.send('balena-update-lock', 'lock')

Releasing the Lock

// Listen for a response
ipcRenderer.once('balena-update-lock', (event, error) => {
  if (error) { ... }
})

// Send the 'unlock' command to release the lock
ipcRenderer.send('balena-update-lock', 'unlock')

Checking the Lock

// Listen for a response
ipcRenderer.once('balena-update-lock', (event, error, isLocked) => {
  console.log('Locked:', error || isLocked)
})

// Send the 'check' command to check on the state of the lock
ipcRenderer.send('balena-update-lock', 'check')

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