Quick start

This document should help you to get started with the Rell developer preview.

Install Docker

A software called Docker is required in order to run the Developer Preview. It can be downloaded from docker.io, you will also have to create an account.

Install the Developer Preview

You will need to create a new directory, download a file and write a command in a terminal. If you are a terminal savvy person, you can do the following (on Mac or GNU/Linux):

mkdir relltest
cd relltest
curl -o ./docker-compose.yml  https://chromapolis.com/devpreview/docker-compose.yml
docker-compose up

Now, when the terminal stops writing, you should be able to try the IDE, see next section.

Alternatively, you can do a manual install.

  1. Create a new direcory
  2. Download this yml file and save it to the new directory.
  3. In the relltest directory, open a terminal and type docker-compose up.

If you do not know how to open a terminal, we suggest you watch our videos below.

Try the IDE

In your browser, look at localhost at port thirty thousand, http://localhost:30000. You should see the Postchain IDE.

Postchain IDE in browser

Select Module (first element in the top bar) and then Create. A new window will appear. Write any name for your module, such as Hello. In the dropdown, select “Rell”, and select the “Use template for code and tests” option.

Where to create a new module

This will open a modal element where to specify the name of the Module and the Language used (in this example: Rell). For convenience you can include template and test code.

Create Module options window

Click the blue “Create” button. The screen will now be filled with code.

The IDE with a template

Browser
To the left bar is the Browser. You can use it to work with several examples.
Editor
Inside the central element on the left the editor filled with a template of source code.
Test window
Inside the central element on the right there is a window with XML. This is a way to run your code, simulating a real application.
Buttons
On top of the Editor there is a button “Start Node”, don’t press that one yet. There is also a button “Run tests”. Click it to see that the test passes.

Hello World!

As a minimal first application, you can make a Hello World example with a focus on Ukraine.

If you checked the use template box and look at editor section on the top, you will see this code as a template:

class city { key name; }

operation insert_city (name) {
    create city (name);
}

This is a small registry of cities. In order to run the code we need a test in XML.

<test>
<block>
    <transaction>
    <signers><param type="bytea" key="Alice"/></signers>
    <operations>
        <operation name="insert_city">
        <string>Kiev</string>
        </operation>
    </operations>
    </transaction>
</block>
</test>

Click the ‘Run tests’ button, and a green message will appear.

The IDE shows Run Succesfully

After all this work, we suggest that you put “Relational Blockchain” on your CV.

Next step is to learn more about Rell in the Tutorial.

However if you feel eager to click the Start Node button and create a complete running application, you can learn how to use the javascript client library in the Client section.

Videos

If you are stuck, we have some videos showing how to get started, on a Mac.

With_docker_installed_installing_developer_preview