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Version: 0.4.0

askui UI Controller Docker Images

We maintain Docker Images for running tests with askui inside a Docker Container, e.g., locally or in a CI/CD pipeline. The Images are based on Ubuntu (amd64) images and contain the askui UI Controller (also known as the UiController) and a browser. Currently, we offer some of the latest versions of Chrome and Firefox. The askui library connects to the askui UI Controller inside the Docker container to execute the test steps inside it. You can find our images on DockerHub.

⚠️ ARM CPUs: are currently not supported


The following environment variables can be used for configuring the Docker Container started from one of our Docker Images:

VariableDefault ValueDescription
ENABLE_VNCfalsetrue to enable VNC so that you can connect and observe whats happening inside the container. The VNC server is bound to port 5900 of the container.
SCREEN_RESOLUTION1920x1080The screen resolution used inside the container in the format <width>x<height>.


The askui UI Controller is bound to port 6769 of the container so this needs to be exposed.

Starting Container Manually

You can pull an Image using docker pull, e.g.,

docker pull askuigmbh/askui-ui-controller:v0.10.0-firefox-82.0.3-amd64

and, then, start the corresponding Container using:

docker run -e ENABLE_VNC=true -p 6769:6769 -p 5900:5900 askuigmbh/askui-ui-controller:v0.10.0-firefox-82.0.3-amd64

Starting Container from Within beforeAll() Using Testcontainers

Testcontainers is a Node.js library that supports starting Docker Containers from within tests and throwing them away afterwards.

To use it, first install it:

npm i -D testcontainers

After that, you can adjust the jest.setup.ts that is created when running npx askui init like in the following example starting the askui UI Controller container just before all tests are run and connecting to it:

import { UiControlClient } from 'askui';
import { GenericContainer, StartedTestContainer } from 'testcontainers';

jest.setTimeout(60 * 1000 * 60);

function getDockerImageName(): string {
const askuiUiControllerVersion = 'v0.10.0';
const browser = 'firefox';
const browserVersion = '82.0.3';
const osArch = 'amd64';
return `askuigmbh/askui-ui-controller:${askuiUiControllerVersion}-${browser}-${browserVersion}-${osArch}`;

async function startTestContainer(): Promise<StartedTestContainer> {
const container = await new GenericContainer(getDockerImageName())
.withEnv('ENABLE_VNC', 'true')
.withEnv('SCREEN_RESOLUTION', '1920x1080')
.withExposedPorts(6769, 5900)

console.log(`VNC link: ${container.getHost()}:${container.getMappedPort(5900)}`);

return container;

let testContainer: StartedTestContainer;

// eslint-disable-next-line import/no-mutable-exports
let aui: UiControlClient;

beforeAll(async () => {
testContainer = await startTestContainer();

aui = await{
uiControllerUrl: `${testContainer.getMappedPort(6769)}`,

await aui.connect();

afterAll(async () => {

await testContainer.stop();

export { aui };

Connect via VNC

To check what is happening inside a running test container, you can connect via VNC. For this, you need a VNC client like Remmina. When starting the Docker Container manually, you have to map the interal port 5900 to a free port on your machine that you, then, can connect to. When using the testcontainers example code, the VNC port to connect to is logged to the console.

When connecting, enter the password askui when asked.

Example of a VNC connection with a Chrome browser running inside a container:

VNC Example