Move to the edge with Azure IoT and resin.io

The benefits of running services on the edge—fast response times- low bandwidth- the ability to work offline—make this approach an attractive alternative to a fully cloud-based model. But there are some things to think about before moving to the edge: * How do you keep the development process simple- so you don’t have to rewrite…

The benefits of running services on the edge—fast response times, low bandwidth, the ability to work offline—make this approach an attractive alternative to a fully cloud-based model. But there are some things to think about before moving to the edge:

  • How do you keep the development process simple, so you don’t have to rewrite your code for devices with different operating systems or architectures?
  • How do you manage software updates, so that all devices in your fleet can easily and regularly get the latest code?
  • What should you do when you require more computing power than your local device can provide?
  • Where should you store important data to make it available to all devices?

Luckily, all of these concerns can be easily addressed with the right combination of services. We recently tested one such combination—resin.io and Microsoft Azure IoT Edge—and we’re excited to share how easy it is to get cloud-backed edge intelligence onto the device of your choice:

The not-so-secret ingredient in our easy deployment solution is the Docker container platform. When you put resinOS on your device, you have the ability to run an application in a Docker container without having to do any heavy lifting. If you take a look at the Dockerfile for this deploy, you’ll see it is very simple:

  • Specify a base image and update with the required libraries:

    FROM resin/raspberrypi3-node

    ENV INITSYSTEM=on

    RUN apt-get update
    RUN apt-get install curl build-essential libcurl4-openssl-dev git cmake pkg-config libssl-dev uuid-dev valgrind jq libglib2.0-dev libtool autoconf autogen vim fbi imagemagick

  • Collect and build the application:

    WORKDIR /usr/src/app
    RUN git clone https://github.com/Azure/iot-edge.git

    WORKDIR /usr/src/app/iot-edge/tools
    RUN ./build.sh –disable-native-remote-modules

  • Run the application:

    WORKDIR /usr/src/app
    COPY start.sh .
    COPY image.png .
    ENTRYPOINT ./start.sh

The start.sh script performs a few configurations tasks prior to launching the application. To understand what it does, know that for this demo we have the RaspberryPi acting as a gateway device passing data from two simulated devices to a central hub. Before the script can be run, these steps should be taken:

  • Create an IoT Hub on the Azure portal and register two devices (similar to the first two steps in this tutorial)
  • Using the resin.io dashboard, store the simulated device IDs and keys as environment variables for the gateway device:

The first task of start.sh is to check for these device credentials. It also does some checks to make sure the display is properly configured:

if [ -z "$DEVICE1" ]
then
  echo "Error: DEVICE1 not set!"
  exit 1
fi


if [ -z "$DEVICE2" ]
then
echo "Error: DEVICE2 not set!"
exit 1
fi




if [ -z "$DEVICE1KEY" ]
then
echo "Error: DEVICE1KEY not set!"
exit 1
fi




if [ -z "$DEVICE2KEY" ]
then
echo "Error: DEVICE2KEY not set!"
exit 1
fi




if [ ! -c /dev/fb1 ]
then
modprobe fbtft_device name=pitft verbose=0 rotate=0
sleep 1
mknod /dev/fb1 c $(cat /sys/class/graphics/fb1/dev | tr ':' ' ')
fi




ROTATE=${ROTATE:-0}
convert image.png -rotate $ROTATE rotated.png
fbi -d /dev/fb1 -T 1 -noverbose -a rotated.png




sleep infinity

Next, start.sh updates the sample configuration file to include the IoT Hub name and simulated device credentials:

J_FILE=$(cat /usr/src/app/iot-edge/samples/simulated_device_cloud_upload/src/simulated_device_cloud_upload_lin.json)

cd into sample dir



cd /usr/src/app/iot-edge/samples/simulated_device_cloud_upload/src/



update settings based on env vars



echo "$J_FILE" | \
jq '.modules[0].args.IoTHubName="<IoTHubName>"' | \
jq '.modules[0].args.IoTHubSuffix="azure-devices.net"' | \
jq '.modules[0].args.Transport="AMQP"' | \
jq '.modules[1].args[0].deviceId="'$DEVICE1'"' | \
jq '.modules[1].args[0].deviceKey="'$DEVICE1KEY'"' | \
jq '.modules[1].args[1].deviceId="'$DEVICE2'"' | \
jq '.modules[1].args[1].deviceKey="'$DEVICE2KEY'"' \
> replaced.json

Then it’s just a matter of kicking off the sample application, immediately sending simulated device data back to the IoT Hub:

# cd back up to build dir
cd /usr/src/app/iot-edge/build/

run gateway with new config file



while true
do
./samples/simulated_device_cloud_upload/simulated_device_cloud_upload_sample ../samples/simulated_device_cloud_upload/src/replaced.json
done

That’s all it takes! Give it a try, and if you run into problems or want to share what you’ve built, please reach out on our forums.

Posted

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Zach Walchuk

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