About

Given the problem of Task 4, step 2.

A company produces a device with pollutants and oxygenation level. It will install several of these devices along a river near a factory to check the water treatment. Due to the simplicity of device, it sends the data corresponding to the two measurements in a 16-bit message, each reading being encoded in 8 bits. Data is sent every hour to a gateway that relays them to dojot via HTTP.

Problem:

Given the limitation of the devices, it will be necessary to convert from 16 bits to 8 bits, separating the messages.

That way, we can use Dojot's Flow Broker to perform this task whenever new data arrives. However, that knot does not yet exist! For the task, you will need to create a new node that will do this conversion.

How to build and add it to Dojot

Build the docker image:

docker build -t <your dockerHub username>/decoder .

Publish it on your DockerHub:

docker push <your dockerHub username>/decoder

Acquire a Dojot's token:

JWT=$(curl -s -X POST http://localhost:8000/auth \
-H 'Content-Type:application/json' \
-d '{"username": "admin", "passwd" : "admin"}' | jq -r ".jwt")

Note: the previous command requires the jq command, you can install it on ubuntu with the following command:

sudo apt-get install jq

Add the node to Dojot.

curl -H "Authorization: Bearer ${JWT}" http://localhost:8000/flows/v1/node -H 'content-type: application/json' -d '{"image": "<your dockerHub username>/decoder", "id":"decoder"}'

Now the decoder node will be available on converters category into the FlowBroker Dojot's interface.

Note: the DockerHub use is optional, you can use a private docker registry instead.

Note2: All commands considers that you are running Dojot locally, if it is not the case, please, adapt them to refect your scenario.