Chapter 2. Che-Theia IDE basics

This section describes basics workflows and commands for Che-Theia: the native integrated development environment for Red Hat CodeReady Workspaces.

2.1. Defining custom commands for Che-Theia

The Che-Theia IDE allows users to define custom commands in a devfile that are then available when working in a workspace.

This is useful, for example, for:

  • Simplifying building, running, and debugging projects.
  • Allowing lead developers to customize workspaces based on team requirements.
  • Reducing time needed to onboard new team members.

See also Section 4.2, “Authoring devfiles version 2”.

2.1.1. Che-Theia task types

The following is an example of the commands section of a devfile.


  - name: Package Native App
      - type: exec
        component: centos-quarkus-maven
        command: "mvn package -Dnative -Dmaven.test.skip"
        workdir: ${CHE_PROJECTS_ROOT}/quarkus-quickstarts/getting-started

  - name: Start Native App
      - type: exec
        component: ubi-minimal
        command: ./getting-started-1.0-SNAPSHOT-runner
        workdir: ${CHE_PROJECTS_ROOT}/quarkus-quickstarts/getting-started/target

  - name: Attach remote debugger
    - type: vscode-launch
      referenceContent: |
          "version": "0.2.0",
          "configurations": [
              "type": "java",
              "request": "attach",
              "name": "Attach to Remote Quarkus App",
              "hostName": "localhost",
              "port": 5005
CodeReady Workspaces commands

Package Native App and Start Native App

The CodeReady Workspaces commands are to be used to define tasks that will be executed in the workspace container.

  • The exec type implies that the CodeReady Workspaces runner is used for command execution. The user can specify the component in whose container the command is executed.
  • The command field contains the command line for execution.
  • The workdir is the working directory in which the command is executed.
  • The component field refers to the container where the command will be executed. The field contains the component alias where the container is defined.
VS Code launch configurations

Attach remote debugger

VS Code launch configurations are commonly used to define debugging configuration. To trigger these configurations, press F5 or choose Start Debugging from the Debug menu. The configurations provide information to the debugger, such as the port to connect to for debugging or the type of the application to debug (Node.js, Java, and others.).

  • The type is vscode-launch.
  • It contains the launch configurations in the VS Code format.
  • For more information about VS Code launch configurations, see the Debugging section on the Visual Studio documentation page.

Tasks of type che, also known as exec commands, can be executed from the Terminal→Run Task menu or by selecting them in the My Workspace panel. Other tasks are only available from Terminal→Run Task. Configurations to start with are available in the Che-Theia debugger.

2.1.2. Running and debugging

Che-Theia supports the Debug Adapter Protocol. This protocol defines a generic way for how a development tool can communicate with a debugger. It means Che-Theia works with all implementations.



To debug an application:

  1. Click DebugAdd Configuration for debugging or adding of a launch configuration to the project.

    che theia basics 1
  2. From the pop-up menu, select the appropriate configuration for the application that you are about to debug.

    che theia basics 2
  3. Update the configuration by modifying or adding attributes.

    che theia basics 3
  4. Breakpoints can be toggled by selecting the editor margin.

    che theia basics 3 b
  5. After opening the breakpoint menu, use the Edit Breakpoint command to add conditions.

    che theia basics 3 c

    The IDE then displays the Expresion input field.

    che theia basics 3 d
  6. To start debugging, click View→Debug.

    che theia basics 4
  7. In the Debug view, select the configuration and press F5 to debug the application. Or, start the application without debugging by pressing Ctrl+F5.

    che theia basics 5

2.1.3. Editing a task and launch configuration


To customize the configuration file:

  1. Edit the tasks.json or launch.json configuration files.
  2. Add new definitions to the configuration file or modify the existing ones.


    The changes are stored in the configuration file.

  3. To customize the task configuration provided by plug-ins, select the TerminalConfigure Tasks menu option, and choose the task to configure. The configuration is then copied to the tasks.json file and is available for editing.

2.2. Version Control

Red Hat CodeReady Workspaces natively supports the VS Code SCM model. By default, Red Hat CodeReady Workspaces includes the native VS Code Git extension as a Source Code Management (SCM) provider.

2.2.1. Managing Git configuration: identity

The first thing to do before starting to use Git is to set a user name and email address. This is important because every Git commit uses this information.


  • To configure Git identity using the CodeReady Workspaces user interface:

    1. Open File > Settings > Open Preferences or press Ctrl+,.

      Configuring Git identity
    2. In the opened window, navigate to the Git → User sub-section and enter the User mail and User name values.
  • To configure Git identity using the command line, open the terminal of the Che-Theia container.

    1. Navigate to the My Workspace view, and open Plugins > theia-ide > New terminal:

      terminal git command
    2. Execute the following commands:

      $ git config --global "John Doe"
      $ git config --global

Che-Theia permanently stores this information in the current container and restores it for other containers on future workspace starts.

2.2.2. Accessing a Git repository using HTTPS


To clone a repository using HTTPS:

  1. Use the clone command provided by the Visual Studio Code Git extension.

Alternatively, use the native Git commands in the terminal to clone a project.

  1. Navigate to destination folder using the cd command.
  2. Use git clone to clone a repository:

    $ git clone <link>

    Red Hat CodeReady Workspaces supports Git self-signed TLS certificates. See Deploying CodeReady Workspaces with support for Git repositories with self-signed certificates to learn more.

2.2.3. Accessing a Git repository using a generated SSH key pair Generating an SSH key using the CodeReady Workspaces command palette

You can generate an SSH key by using the CodeReady Workspaces command palette. You have to create a unique SSH key for each Git provider in use because each SSH key restricts permissions for one specific Git provider.

A common SSH key pair that works with all the Git providers is available by default. To start using it, add the public key to the Git provider.



  1. Generate an SSH key pair that only works with a particular Git provider:

    • In the CodeReady Workspaces IDE, press F1 to open the Command Palette, or navigate to View → Find Command in the top menu.

      The command palette can be also activated by pressing Ctrl+Shift+p (or Cmd+Shift+p on macOS).

    • Search for SSH: generate key pair for particular host by entering generate into the search box and pressing Enter once filled.
    • Provide the hostname for the SSH key pair such as, for example,

      The SSH key pair is generated.

  2. Click the View button in the lower-right corner and copy the public key from the editor and add it to the Git provider.

    It is possible to use another command from the command palette: Clone git repository by providing an SSH secured URL. Adding the associated public key to a repository or account on GitHub

To add the associated public key to a repository or account on GitHub:

  1. Navigate to
  2. Click the drop-down arrow next to the user icon in the upper right corner of the window.
  3. Click SettingsSSH and GPG keys and then click the New SSH key button.
  4. In the Title field, type a title for the key, and in the Key field, paste the public key copied from CodeReady Workspaces.
  5. Click the Add SSH key button. Adding the associated public key to a Git repository or account on GitLab

To add the associated public key to a Git repository or account on GitLab:

  1. Navigate to
  2. Click the user icon in the upper right corner of the window.
  3. Click SettingsSSH Keys.
  4. In the Title field, type a title for the key and in the Key field, paste the public key copied from CodeReady Workspaces.
  5. Click the Add key button.

2.2.4. Managing pull requests using the GitHub PR plug-in

To manage GitHub pull requests, the VS Code GitHub Pull Request plug-in is available in the list of plug-ins of the workspace. Using the GitHub Pull Requests plug-in



  • Sign in to GitHub, using the Accounts menu or the Sign in button in the plugin’s view:

    github sign in action

To sign out from GitHub use the Accounts menu in the left bottom side, or GitHub Pull Requests: Sign out of GitHub command.

2.3. Che-Theia Troubleshooting

This section describes the most frequent issues with the Che-Theia IDE.

Che-Theia shows a notification with the following message: Plugin runtime crashed unexpectedly, all plugins are not working, please reload the page. Probably there is not enough memory for the plugins.

This means that one of the Che-Theia plug-ins that are running in the Che-Theia IDE container requires more memory than the container has. To fix this problem, increase the amount of memory for the Che-Theia IDE container:

  1. Navigate to the CodeReady Workspaces Dashboard.
  2. Select the workspace in which the problem happened.
  3. Switch to the Devfile tab.
  4. In the components section of the devfile, find a component of the cheEditor type.
  5. Add a new property, memoryLimit: 1024M (or increase the value if it already exists).
  6. Save changes and restart the workspace.

2.4. Differences in Che-Theia Webview in single-host mode and multihost mode

Depending on which Che deployment strategy is used, single-host or multihost, there are differences in how Che-Theia Webview API works.

2.4.1. What’s a Webview

Webview Plug-in API allows creating a view within Che-Theia to show an arbitrary HTML content. Internally, it’s implemented with an iframe and service worker.

2.4.2. Webview in multihost mode

When Red Hat CodeReady Workspaces is deployed in multihost mode, Webview content is served on a separate origin. That means it’s isolated from the main Che-Theia context. So, a contributed view has no access:

  • to the top-level DOM
  • to the Che-Theia state, like local storage, cookies, and so on.

2.4.3. Webview in single-host mode

When Red Hat CodeReady Workspaces is deployed in single-host mode, Webview content is loaded through the same origin as the main Che-Theia context. It means that nothing prevents external content from accessing the main Che-Theia in a browser. So, pay extra attention to what content may be loaded by different Plugins that contribute the Webviews.