Connection refused error with selenium running in docker - selenium

Question

While trying nto dockerise selenium End2End tests using the selenium docker image 'selenium/standalone' i get the error : Error retrieving a new session from the selenium server Connection refused! Is selenium server started?
ye selenium server starts up according to the console output..any ideas ?
FROM selenium/standalone-chrome
USER root
# installing node
RUN apt-get update
RUN apt-get install -y curl
RUN curl -sL https://deb.nodesource.com/setup_7.x | bash
RUN apt-get install -y nodejs
RUN node -v
RUN npm -v
# Installing Yarn
#RUN rm -r /usr/local/bin/yarn
RUN npm install -g -y yarn
ENV PATH $PATH:/usr/local/bin/yarn
#copying files
WORKDIR /app
COPY . .
# debug
RUN ls -alh .
#installing yarn
RUN yarn install
EXPOSE 4444
RUN yarn
CMD yarn test

Answer 1

The problem is your approach of solving this. See you are inheriting your image from selenium/standalone-chrome which is supposed to run a Selenium browser. Now is this image you are adding your tests and specifying the CMD to run the tests.
When you build and launch this image, you don't get any browser because the CMD has been overridden by you to run the test. When we build in docker we keep dependent services in different containers. It is preferred to run 1 service/process per container in most case. In your case when the test is run the browser server process is missing, so that is the reason for connection refused.
So you need to be running two containers here. One for selenium/standalone-chrome and one for your test.
Also your image should inherit from node: and not from selenium chrome image. You should not have node -v and npm -v commands also while building images. They create extra layers in your final image
FROM node:7
USER root
# installing node
RUN apt-get update && apt-get install -y curl
# Installing Yarn
RUN npm install -g -y yarn
ENV PATH $PATH:/usr/local/bin/yarn
#copying files
WORKDIR /app
COPY . .
# debug
#installing yarn
RUN yarn install
RUN yarn
CMD yarn test
Now you need to create a docker-compose file to run a composition which has both your test and chrome
version: '3'
services:
chrome:
image: selenium/standalone-chrome
tests:
build: .
depends_on:
- chrome
Install docker-compose and run docker-compose up command to run the above composition. Also in your tests make sure to use the URL as http://chrome:4444/wd/hub and use the Remote webdriver and not the local driver.

Answer 2

i used a selenium/node-chrome image, but what resolved it was making sure my chromedriver + selenium server + nightwatch were set to the latest versions in my package.json