Passing a selenium docker container IP to a ruby cucumber script - ruby

Question

I'm attempting to put a ruby Cucumber test into Docker. I'm using a docker-compose.yml file to start a selenium hub container along with a chrome and firefox node. Then I'm building an alpine ruby based image with my tests.
I've gotten the process to work, however it involves finding the IP of the hub container each time it is built, and then hardcoding the IP into my env.rb file where I connect to the Selenium grid.
I've seen that containers that are linked can be connected using the name but haven't had much luck there. Is there any way I can easily pass the hub container IP to my test's container?
Here is my yml file:
version: "3"
services:
hub:
image: selenium/hub
ports:
- "4444:4444"
environment:
GRID_MAX_SESSION: 16
GRID_BROWSER_TIMEOUT: 3000
GRID_TIMEOUT: 3000
chrome:
image: selenium/node-chrome
container_name: web-automation_chrome
depends_on:
- hub
environment:
HUB_PORT_4444_TCP_ADDR: hub
HUB_PORT_4444_TCP_PORT: 4444
NODE_MAX_SESSION: 4
NODE_MAX_INSTANCES: 4
volumes:
- /dev/shm:/dev/shm
ports:
- "9001:5900"
links:
- hub
firefox:
image: selenium/node-firefox
container_name: web-automation_firefox
depends_on:
- hub
environment:
HUB_PORT_4444_TCP_ADDR: hub
HUB_PORT_4444_TCP_PORT: 4444
NODE_MAX_SESSION: 2
NODE_MAX_INSTANCES: 2
volumes:
- /dev/shm:/dev/shm
ports:
- "9002:5900"
links:
- hub
myapp:
build: .
image: justinpshields/myapp
depends_on:
- hub
environment:
URL: hub
links:
- hub
networks:
default:

Answer 1

links is useless. Every container in a docker-compose.yml share the same network unless stated otherwise.
You should also wait until the selenium hub start and attach its browsers containers.
For instance with that:
while ! curl -sSL "http://$SELENIUMHUBHOST:4444/status" 2>&1 | grep "\"ready\": true" >/dev/null; do
echo 'Waiting for the Grid'
sleep 1
done
while ! curl -sSL "http://$SELENIUMHUBHOST:4444/status" 2>&1 | grep "\"browserName\": \"$BROWSER\"" >/dev/null; do
echo "Waiting for the node $BROWSER"
sleep 1
done