RaspberryPi

How to Run IoT.js on the Raspberry PI 0

Article originaly published at:

• https://s-opensource.org/
• https://js.foundation/blog/2018/03/22/how-to-run-iot-js-on-the-raspberry-pi-0

IoT.js is a lightweight JavaScript platform for building Internet of Things devices; this article will show you how to run it on a few dollars worth of hardware. The First version of it was released last year for various platforms including Linux, Tizen, and NuttX (the base of Tizen:RT). The Raspberry Pi 2 is one of the reference targets, but for demo purposes we also tried to build for the Raspberry Pi Zero, which is the most limited and cheapest device of the family. The main difference is the CPU architecture, which is ARMv6 (like the Pi 1), while the Pi 2 is ARMv7, and the Pi 3 is ARMv8 (aka ARM64).

IoT.js upstream uses a python helper script to crossbuild for supported devices, but instead of adding support to new device I tried to build on the device using native tools with cmake and the default compiler options; it simply worked! While working on this, I decided to package iotjs for debian to see how well it will support other architectures (MIPS, PPC, etc), we will see.

Unfortunately, Debian armel isn’t optimized for ARMv6 and FPU, both of which are present on the Pi 1 and Pi 0, so the Raspbian project had to rebuild Debian for the ARMv6+VFP2 ARM variant to support all Raspberry Pi SBC’s.

In this article, I’ll share hints for running IoT.js on Raspbian: the OS officially supported by the Raspberry foundation; the following instructions will work on any Pi device since a portability strategy was preferred over optimization. I’ll demonstrate three separate ways to do this: from packages, by building on the device, and by building in a virtual machine. By the way, an alternative to consider is to rebuild Tizen Yocto for the Pi 0, but I’ll leave that as an exercise for the reader, you can accomplish this with a bitbake recipe, or you can ask for more hints in the comments section.

Install from Packages

iotjs landed in Debian’s sid, and until it is in testing branch (and subsequently Raspbian and Ubuntu), the fastest way is to download it is via precompiled packages from my personal Raspbian repo.

url='https://dl.bintray.com/rzr/raspbian-9-armhf'
source="/etc/apt/sources.list.d/bintray-rzr-raspbian-9-armhf.list"
echo "deb $url raspbian main" | sudo tee "$source"
sudo apt-get update
apt-cache search iotjs
sudo apt-get install iotjs
/usr/bin/iotjs
Usage: iotjs [options] {script | script.js} [arguments]

Use it

Usage is pretty straightforward, start with a hello world source:

echo 'console.log("Hello IoT.js !");' > example.js
iotjs  example.js 
Hello IoT.js !

More details about the current environment can be used (this is for iotjs-1.0 with the default built-in modules):

echo 'console.log(JSON.stringify(process));' > example.js
iotjs  example.js 
{"env":{"HOME":"/home/user","IOTJS_PATH":"","IOTJS_ENV":""},"native_sources":{"assert":true,"buffer":true,"console":true,"constants":true,"dns":true,"events":true,"fs":true,"http":true,"http_client":true,"http_common":true,"http_incoming":true,"http_outgoing":true,"http_server":true,"iotjs":true,"module":true,"net":true,"stream":true,"stream_duplex":true,"stream_readable":true,"stream_writable":true,"testdriver":true,"timers":true,"util":true},"platform":"linux","arch":"arm","iotjs":{"board":"\"unknown\""},"argv":["iotjs","example.js"],"_events":{},"exitCode":0,"_exiting":false} null 2

From here, you can look to use other built-in modules like http, fs, net, timer, etc. Need More Features?

More modules can be enabled in the master branch, so I also built snapshot packages that can be installed to enable more key features like GPIO, I2C, and more. For your convenience, the snapshot package can be installed to replace the latest release:

root@raspberrypi:/home/user$ apt-get remove iotjs iotjs-dev iotjs-dbgsym iotjs-snapshot
root@raspberrypi:/home/user$ aptitude install iotjs-snapshot
The following NEW packages will be installed:
  iotjs-snapshot{b}
(...)
The following packages have unmet dependencies:
 iotjs-snapshot : Depends: iotjs (= 0.0~1.0+373+gda75913-0~rzr1) but it is not going to be installed
The following actions will resolve these dependencies:
     Keep the following packages at their current version:
1)     iotjs-snapshot [Not Installed]                     
Accept this solution? [Y/n/q/?] n
The following actions will resolve these dependencies:

     Install the following packages:                 
1)     iotjs [0.0~1.0+373+gda75913-0~rzr1 (raspbian)]
Accept this solution? [Y/n/q/?] y
The following NEW packages will be installed:
  iotjs{a} iotjs-snapshot 
(...)
Do you want to continue? [Y/n/?] y
(...)
  iotjs-snapshot https://dl.bintray.com/rzr/raspbian-9-armhf/iotjs-snapshot_0.0~1.0+373+gda75913-0~rzr1_armhf.deb
  iotjs https://dl.bintray.com/rzr/raspbian-9-armhf/iotjs_0.0~1.0+373+gda75913-0~rzr1_armhf.deb

Do you want to ignore this warning and proceed anyway?
To continue, enter "yes"; to abort, enter "no": yes
Get: 1 https://dl.bintray.com/rzr/raspbian-9-armhf raspbian/main armhf iotjs armhf 0.0~1.0+373+gda75913-0~rzr1 [199 kB]
Get: 2 https://dl.bintray.com/rzr/raspbian-9-armhf raspbian/main armhf iotjs-snapshot armhf 0.0~1.0+373+gda75913-0~rzr1 [4344 B]
(...)

If you the run console.log(process) again, you’ll see more interesting modules to use, like gpio, i2c, uart and more, and external modules can be also used; check on the work in progress for sharing modules to the IoT.js community. Of course, this can be reverted to the latest release by simply installing the iotjs package because it has higher priority than the snapshot version.

root@raspberrypi:/home/user$ apt-get install iotjs
(...)
The following packages will be REMOVED:
  iotjs-snapshot
The following packages will be upgraded:
  iotjs
(...)
Do you want to continue? [Y/n] y
(...)

Build on the Device

It’s also possible to build the snapshot package from source with extra packaging patches, found in the community branch of IoT.js (which can be rebased on upstream anytime).

sudo apt-get install git time sudo
git clone https://github.com/tizenteam/iotjs
cd iotjs
./debian/rules
sudo debi

On the RaspberryPi 0, it took less than 30 minutes over NFS for this to finish. If you want to learn more you can follow similar instructions for building IoTivity on ARTIK; it might be slower, but it will extend life span of your SD Cards.

Build on a Virtual Machine

A faster alternative that’s somewhere between building on the device and setting up a cross build environment (which always has a risk of inconsistencies) is to rebuild IoT.js with QEMU, Docker, and binfmt.

First install docker (I used 17.05.0-ce and 1.13.1-0ubuntu6), then install the remaining tools:

sudo apt-get install qemu qemu-user-static binfmt-support time
sudo update-binfmts --enable qemu-arm

docker build 'http://github.com/tizenteam/iotjs.git'

It’s much faster this way, and took me less than five minutes. The files are inside the container, so they need to be copied back to host. I made a helper script for setup and to get the deb packages ready to be deployed on the device (sudo dpkg -i *.deb) :

curl -sL https://rawgit.com/tizenteam/iotjs/master/run.sh | bash -x -
./tmp/out/iotjs/iotjs-dbgsym_0.0-0_armhf.deb
./tmp/out/iotjs/iotjs-dev_0.0-0_armhf.deb
./tmp/out/iotjs/iotjs_0.0-0_armhf.deb

I used the Resin/rpi-raspbian docker image (thanks again Resin!). Finally, I want to also thank my coworker Stefan Schmidt for the idea after he setup a similar trick for EFL’s CI. Further Reading

If you want to learn more, here are some additional resources to take your understanding further.

The IoT.js Main Website
IoT.js Wiki
IoT.js Introduction at FOSDEM

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LICENSE: CC-BY-SA-4.0

• https://creativecommons.org/licenses/by-sa/4.0/