Docker refuses to work on my localhost:3000 port

The problem is that the container doesn't know you localhost hostname, because it is running inside an isolated docker network. If you want your container to know your local network, you have to Use host networking and the container's network stack is not isolated from the Docker host.EG:

    version: '3.2'        # run Cypress tests and exit with command    #   docker-compose up --exit-code-from cypress    services:      cypress:        # the Docker image to use from https://github.com/cypress-io/cypress-docker-images        image: "cypress/included:5.0.0"        environment:          - CYPRESS_baseUrl=http://localhost:3000        # share the current folder as volume to avoid copying        working_dir: /e2e        command: "--browser chrome"        network_mode: "host"        ports:        - 3333:3000        volumes:          - ./:/e2e

baseUrl can be set in your configuration file (cypress.json by default) - and then you can set an environment variable in your OS to override it like shown below.

Try to using CYPRESS_BASE_URL instead of CYPRESS_baseUrl

And make sure that you using network_mode: "host" in docker-compose file.

Another way, you can define baseUrl in crypess.json and add volume to docker container:

e2e-chrome:  image: "cypress/included:4.1.0"  # container_name: cypress  # "cypress/included" images have entrypoint set to globally installed cypress  # so the command can simply add any arguments  command: "--browser chrome"  volumes:    - ./cypress.json:/cypress.json

Refer: docker-compose.yml

version: '3.2'# run Cypress tests and exit with command#   docker-compose up --exit-code-from cypressservices:  cypress:    image: "cypress/included:5.2.0"    environment:      - CYPRESS_BASE_URL=http://host.docker.internal:3000    working_dir: /user-management-ui    #command: "--browser chrome"    network_mode: "host"    volumes:      - ./:/user-management-ui

With my setup, I use docker-compose to create a network, then my services use that network to talk to each other. I have a node container, and another cypress container.

networks:  custom:    driver: bridge

To run my cypress tests through docker, I have to point the cypress container to the node container, which runs the server. In my docker-compose, the node container is called node which will also be the hostname. So my docker-compose has a CYPRESS_BASE_URL environment variable, which overrides the default cypress baseUrl of http://localhost:3000

services:  node:    image: ...    container_name: node    volumes:      - ./:/home/node/app    networks:      - custom    ports:      - '3000:3000'    ...other config  cypress:    image: ...    container_name: cypress    volumes:      - ./:/home/node/app    networks:      - custom    working_dir: /home/node/app    environment:      - DISPLAY=      - CYPRESS_BASE_URL=http://node:3000/ -> I can't configure this, because I'm working with external API, I don't have access to API only via http://localhost:3000

cypress.json:

{    "baseUrl": "http://localhost:3000/",    ...}

To run tests, I first exec into the node container to start the node server, which listens on http://localhost:3000, (http://node:3000)

docker exec -it node bash

then build and run your project (npm start)

then in a different terminal, exec into cypress container

docker exec -it cypress bash

then run tests:

cypress run