IntelliJ IDEA 2021.1 Help

Getting Started with Erlang

IntelliJ IDEA provides Erlang support. IntelliJ IDEA recognizes *.erl files, and allows you to edit them providing full range of coding assistance.

Install the required tools

Install the Erlang plugin in IntelliJ IDEA

  1. In the Settings/Preferences dialog Ctrl+Alt+S, select Plugins.

  2. Switch to the Marketplace tab and type Erlang in the search field.

  3. Once the plugin is found, click Install.

  4. Appy the changes and close the dialog. Restart the IDE if prompted.

    Installing the Erlang plugin

Install Erlang OTP

The first thing for setting up an Erlang environment is installing Erlang OTP, a set of Erlang libraries essential for development.

  1. Install Erlang OTP using the instruction that corresponds to your operating system:

    • Download the Erlang OTP package and run the installation wizard.

    • Once the installation is over, add the installation path plus \bin to the PATH environment variable.

    Run the following command in the terminal:

    Run the following command in the terminal (make sure that you have the apt-get utility):

    apt-get install erlang
  2. To verify that Erlang OTP is installed correctly, run the Erlang shell by running erl in the terminal:

    Verifying the Erlang OTP is installed correctly

    For more information about the Erlang shell, refer to the Erlang documentation.

Install and configure Rebar

In addition to Erlang OTP, you’ll also need Rebar, a build tool that helps compile and test Erlang applications.

  1. The easiest way to install it on your machine is to download its sources and build it locally:

    git clone git:// $ cd rebar $ ./bootstrap Recompile: src/getopt ... Recompile: src/rebar_utils ==> rebar (compile)

    You now have a self-contained script called "rebar" in your current working directory. Place this script to a meaningful location so that you can use rebar to build OTP-compliant apps.

  2. In the Settings/Preferences, go to Other Settings | Erlang External Tools and specify the path to Rebar, so that IntelliJ IDEA can run Rebar commands from the IDE.

    Specifying the path to Rebar

Configure the Erlang SDK

One more thing you’ll have to do to configure IntelliJ IDEA is to add an Erlang SDK.

To do that, change the structure of the default project.

  1. Open the default project structure in one of the two ways:

    • On the Welcome screen, go to Configure | Project Defaults | Project Structure.

    • From the main menu, select File | New Projects Settings | Structure for New Projects.

  2. Add the Erlang SDK by specifying the path to the Erlang OTP installation directory.

    Configuring the Erlang SDK

    If you don’t know where Erlang OTP was installed, check the following directories:

    • Windows: C:\Program Files\erl<version>

    • Linux: /usr/lib/erlang/<version>

    • MacPorts, macOS: /opt/local/lib/erlang/<version>

    • Homebrew, macOS: /usr/local/Cellar/erlang/<version>

Create a new project

Create an Erlang project

There are several ways to create a new Erlang project. The easiest one is to use the Create a new project from the Welcome screen.

Click New Project:

Erlang create new project

Then choose Erlang in the left pane, and click Next.

Erlang create new project erlang

IntelliJ IDEA prompts you to choose an Erlang SDK (which you've already configured):

Erlang create new project sdk

After that you’ll be asked to specify the name of your project and its directory. The following image shows the resulting Erlang project with the name ErlangDemo:

Erlang project

Create a Rebar project

Instead of a pure Erlang project, you might want to create a Rebar project. To do that, type the following code at the Terminal prompt:

rebar create-app appid=<project name>

Once the project has been created, import it into IntelliJ IDEA to make it possible to open this project in the IDE.

Import a project into IntelliJ IDEA

You can import a project into IntelliJ IDEA in several ways. Let's explore importing from the Welcome screen.

On the Welcome screen, press Ctrl+Shift+A, type project from existing sources, and click the Import project from existing sources action in the popup.

In the dialog that opens, select the directory in which your sources, libraries, and other assets are located and click Open.

IntelliJ IDEA offers you to either import the project from existing sources, or from an external model (a build file).

If your project uses Rebar, select the corresponding option when asked.

Erlang import project

When importing a Rebar project, make sure to enable the option Fetch dependencies with rebar:

Erlang import project fetch

Run and debug an application

To run an application, you have to create a run/debug configuration created against the stub Erlang Application. To do this, on the main menu choose Run | Edit Configurations, select the stub Erlang Application, specify the name (here it is hello.hello_world ), and specify the application’s module and function:

Erlang run config

After that you’ll be able to run your application via the main menu (Run | Run <run configuration name>, the toolbar Icons toolwindows tool window run, or a even a shortcut Ctrl+Shift+F10.

Once you have a run/debug configuration, you can also debug your application via the main menu (Run | Debug ‘<run configuration name>, the toolbar Icons actions start debugger, or a shortcut Shift+F9:

Erlang debug

For more information, refer to the concept of a run/debug configuration and the procedural sections Run applications and Debug code.

Running Eunit tests

Running Eunit tests is similar to running an application, but needs a different run/debug configuration, created against the stub Erlang Eunit:

Erlang eunit config

IntelliJ IDEA provides a handy Test Runner with support for Eunit. It shows test results, lets you rerun tests of you choice, jump to failed tests, etc.:

Erlang test

Running Rebar commands

Running Rebar commands is also possible right from the IDE – with the help of the Erlang Rebar run/debug configuration:

Erlang rebar run config

Note that if your Rebar commands run tests, you can use a Erlang Rebar Eunit run/debug configuration to see test results in a Test Runner.


Learning Erlang

To learn Erlang, we recommend that you start by reading the official Erlang user guide, and of course the Learn You Some Erlang for Great Good tutorial by Fred Hebert.

Learning IntelliJ IDEA

IntelliJ IDEA is a Java IDE in the first place, however it’s also a platform and IDE for other languages, such as Erlang, Python, Ruby, PHP, and many other. To learn more about IntelliJ IDEA, it’s worth checking out the section IntelliJ IDEA overview and watch the Video Tutorials.

If you have a question, you can always ask it on StackOverflow (probably it’s already answered).

Providing Feedback

In case you’d like to share your feedback about IntelliJ IDEA or its support for Erlang, feel free to submit an issue in Erlang plugin GitHub repository, or to the IntelliJ IDEA issue tracker.

For information about contacting JetBrains support, see Getting started.

Last modified: 14 April 2021