Eclipse IDE



  • Java 8+.
  • To be able to run a Postchain node: PostgreSQL 10.

Using a full Rell Eclipse IDE bundle

Rell Eclipse IDE can be downloaded here:

Download an archive for your OS.

  • Linux: unpack, run eclipse
  • Windows: unpack, run eclipse.exe
  • MacOS: open the DMG image, run or install Eclipse.

Adding Rell plugin to an existing Eclipse IDE

If you already have an Eclipse IDE (for example, Eclipse IDE for Java), the Rell plugin can be added to it.

  1. Go to the menu Help - Install New Software…

  2. In the Install dialog, click Add…, then type:

  3. Rell shall appear in the list. Select it and click Next >, then Finish.

  4. When seeing a warning “You are installing software that contains unsigned content”, click Install anyway.

  5. Click Restart Now when asked to restart Eclipse IDE.

  6. Switch to the Rell perspective. Menu Window - Perspective - Open Perspective - Other…, choose Rell.


Next step is to create a Rell project (see Hello World Program).

How to update the Rell plugin

When a new version of the Rell plugin is released, it has to be updated in Eclipse. If Rell update URL has already been configured, Eclipse will check for updates automatically once in a while, and show a message when a plugin can be updated.

To manually check for updates:

  1. Menu: Help - Check for Updates.
  2. If it shows that a new version of Rell plugin is available, install it.

If “No updates found” message is shown, check that Rell update site is set up.

  1. Click available software sites link in the message dialog.

  2. If there is no Rell in the list, click Add… to add it.

  3. Specify:

    and click Add.

If Rell update site is in the list, but “No updates found” message is shown, try to reload the site:

  1. Click available software sites link in the message dialog.
  2. Click Reload.

If still no updates are shown, your Rell plugin must be already up-to-date.

Database Setup

Rell requires PostgreSQL 10 to be installed and set up. The IDE can work without it, but will not be able to run a node. A console app or a remote postchain app can be run without a database, though.

Default database configuration for Rell is:

  • database: postchain
  • user: postchain
  • password: postchain

Ubuntu (Debian)

Install PostgreSQL:

sudo apt-get install postgresql

Prepare a Rell database:

sudo -u postgres psql -c "CREATE DATABASE postchain;" -c "CREATE ROLE postchain LOGIN ENCRYPTED PASSWORD 'postchain'; GRANT ALL ON DATABASE postchain TO postchain;"


Install PostgreSQL:

brew install postgresql
brew services start postgresql
createuser -s postgres

Prepare a Rell database:

psql -U postgres -c "CREATE DATABASE postchain;" -c "CREATE ROLE postchain LOGIN ENCRYPTED PASSWORD 'postchain'; GRANT ALL ON DATABASE postchain TO postchain;"

Hello World Program

  1. Switch to the Rell perspective, if not done already. Menu: Window - Perspective - Open Perspective - Other…, choose Rell.

  2. Create a project:

    • Menu File - New - Rell Project.
    • Enter a project name test and click Finish.

    A Rell project with a default directory structure shall be created.

  3. Create a Rell file:

    • Right-click on the src folder and choose New - File.
    • Enter a file name test.rell and click Finish.
  4. Write the code in the editor:

    function main() {
        print('Hello, World!');

    Save: manu File - Save or CTRL-S (⌘S).

  5. Run the program: right-click on the editor and choose Run As - Rell Console App.

  6. The output “Hello, World!” must be shown in the Console view.


IDE Overview

Eclipse IDE window consists of different views. Every view has its own tab. By default, Rell IDE has following views:

  • Project Explorer - shows projects and their directory trees.
  • Problems - shows compilation warnings and errors.
  • Console - console output (when running programs).
  • Outline - shows the structure of a selected Rell file.

Running Applications

Right-click on a file (or an editor) and choose Run As. Run options available for the file will be shown.


Alternatively, use keyboard shortcut CTRL-F11 (⇧⌘F11).


Rell Console App

Executes a *.rell file as a stand-alone console program, not as a module in a Postchain node.

The program must contain a function (or operation, or query) called main, which will be the entry point. The output is displayed in the Console view.

The name of the main function and its arguments can be specified in a run configuration.

Database connection

By default, the program is executed without a database connection, and an attempt to perform a database operation will result in a run-time error.

To run a console app with a database connection, there must be a file called, or in the directory of the Rell file or in the rell/config directory of the project. The file shall contain database connection settings. For example:


When running a console app with a database connection, tables for defined classes and objects are created on start-up. If a table already exists, missing columns are added, if necessary.

How to prepare a database is described in the Database Setup section.

Rell Simple Postchain App

Starts a Postchain node running the given Rell module.

A database connection and other standard Postchain node properties must be specified in a file. The file is searched in the directory of the selected Rell file and then in the rell/config directory.

If the properties file is not found, the IDE offers to create a default one; click Yes.


If a database configuration which is different from the default for Rell (postchain/postchain/postchain as database/user/password) has to be used, specify it in the created file. Then run the app again.

Rell program output and Postchain node log is shown in the Console view. To stop a node, click the Terminate (red square) icon in the Console view.


One can use curl to call a query from the running node:

curl http://localhost:7740/query/0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF -X POST -d '{"type":"q"}'

By default, the blockchain RID is 0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF. It can be changed in a run configuration.

Rell Postchain App

Starts a Postchain node with a configuration written in the Run.XML format. To use this option, right-click on a *.xml file, not on a *.rell file.

Using run.xml allows to run multiple blockchains in one Postchain node.

Example of a minimal run.xml:





        <chain name="user" iid="1" brid="01234567abcdef01234567abcdef01234567abcdef01234567abcdef01234567">
                <module src="main" />

Rell Simple Postchain Test

Runs tests written in XML format, same as used by the Web IDE. This run option is available for XML files *_test.xml. For a file X_test.xml there must be a file called X.rell in the same directory. The tests defined in the XML file will be run against the Rell file. Results are printed to the Console view.

Example of a test:

                <param type="bytea" key="Alice" />
                <operation name="insert_city">

And a corresponding .rell file:

class city { key name; }

operation insert_city (name) {
    log('insert_city', name);
    create city (name);

Clear Database

This option is available for database properties files, *.properties (for instance, Drops all tables (and stored procedures) in the database.


Run with a Keyboard

By default, CTRL-F11 (⇧⌘F11) shortcut runs the file of the active editor. It can be configured to run the last launched application instead, which may be more convenient, as there is no need to choose an application type. Go to the menu Window - Preferences (macOS: Eclipse - Preferences), then Run/Debug - Launching. In the Launch Operation box, choose Always launch the previously launched application.


Running Multiple Apps

It is possible to run multiple applications (e. g. multiple nodes) simultaneously. For example, one can define two Run.XML configuration files that use the same Rell module, but different ports and database schemas.

The output of all running applications will be shown in the Console view, but on different pages. It is possible to switch between the consoles of different applications using a button or a dropdown list.


Run Configurations

To run an application, Eclipse IDE needs a run configuration, which contains different properties, like the name of the main function, arguments or blockchain RID. When running an application via the Run As context menu, the IDE automatically creates a run configuration with default settings if it does not exist.

To change a run configuration, go to the menu Run - Run Configurations…. The last launched application will be selected. Change the settings and click either Apply or Run to save the changes.


Features of the IDE


When a Rell editor is open, the structure of its file (tree of definitions) is shown in the Outline view (which is by default on the right side of the IDE).


There is also a Quick outline window, which is activated by the CTRL-O (⌘O) shortcut. Type a name to find its definition in the file.

../_images/outline_popup_ed.png ../_images/outline_popup_4.png

Problems View

Problems view shows compiler warnings and errors found in all projects in the IDE. The list is updated when saving a file.



Git operations are available via a context menu: right-click on a file and choose Team.


To commit file(s), click Add to Index, then Commit...

File icon in the Project Explorer indicates whether the file is a new, changed or an unmodified file.


Changed files do not look very nice. To change the way how they are displayed, go to the Window - Preferences (macOS: Eclipse - Preferences) menu, then Team - Git - Label Decorations:

  • on the Text Decorations tab: delete the “>” character in all text fields

  • on the Icon Decoartions tab: check the Dirty resources checkbox

  • click Apply and Close

Now files look much better:


Spaces vs. Tabs

Eclipse uses tabs instead of spaces by default. It is recommented to use spaces. A few settings have to be changed:

  1. Open the Preferences dialog: menu Window - Preferences (macOS: Eclipse - Preferences).

  2. Type “tabs” in the search box.

  3. Go to General - Editors - Text Editors and check Insert spaces for tabs.

  4. Go to XML - XML Files - Editor, select Indent using spaces, specify Indentation size: 4.



  • To show or hide line numbers: right-click on the left margin of an editor, click Show Line Numbers.

  • To comment a code fragment, select it and press CTRL-/ (⌘/).

  • Activate the Link with Editor icon, and the IDE will automatically select a file in the Project Explorer when its editor is focused.

  • CTRL-SHIFT-R (⇧⌘R) invokes the Open Resource dialog, which allows to search project files by name. Glob patterns (with * and ?) are supported.

  • The Show Whitespace Characters (paragraph) icon in the main toolbar allows to distinguish tabs from spaces.

  • To see the full list of Eclipse keyboard shortcuts, press CTRL-SHIFT-L (⇧⌘L). Some shortcuts are for the Java editor, and do nothing in Rell.


Keyboard shortcuts

Most useful keyboard shortcuts (subjectively):

Action Linux/Windows macOS
Run the file shown in the active editor CTRL-F11 ⇧⌘F11

Show the New wizard CTRL-N ⌘N
Show the New menu ALT-SHIFT-N ⌥⌘N
Save the current file CTRL-S ⌘S
Close the active editor tab CTRL-W ⌘W
Close all editor tabs CTRL-SHIFT-W ⇧⌘W

Quick outline CTRL-O ⌘O
Find text in the active editor CTRL-F ⌘F
Globally search for the selected text fragment CTRL-ALT-G ⌥⌘G
Show global text search dialog CTRL-H ^H
Find a file by name CTRL-SHIFT-R ⇧⌘R

Go to a line number CTRL-L ⌘L
Go to a previous location ALT-Left ⌥⌘←
Go to a next location (can be used after Alt-Left) ALT-Right ⌥⌘→
Go to the last edit location CTRL-Q ⌘Q

Comment the selected code fragment with // CTRL-/ ⌘/
Convert selected text to upper case CTRL-SHIFT-X ⇧⌘X
Convert selected text to lower case CTRL-SHIFT-Y ⇧⌘Y

Show the full list of keyboard shortcuts CTRL-SHIFT-L ⇧⌘L