Test the connection between docker containers within docker-composed environment - docker

Question

We are using docker-compose to set up the services for our app:
version: "3"
services:
db:
container_name: db
image: postgres:11.1
environment:
POSTGRES_USER: xxx
POSTGRES_PASSWORD: xxx
POSTGRES_DB: xxx
PGPASSWORD: xxx
volumes:
- pgdata:/var/lib/postgresql/data
- ./data/dbdump:/dbdump
networks:
- zenet
ports:
- "5432:5432"
# The React web application
web:
container_name: web
build:
context: .
dockerfile: devenv/web/Dockerfile
volumes:
- ./src/client-app:/usr/local/abc
- /usr/local/abc/node_modules
networks:
- zenet
ports:
- "3000:3000"
command: npm run startindocker
# The Django Rest Framework API
api:
container_name: api
build:
context: .
dockerfile: devenv/api/Dockerfile
environment:
DJANGO_SETTINGS_MODULE: abc.settings.dev
PYTHONSTARTUP: /root/pythonstartup.sh
PYTHONIOENCODING: UTF-8
volumes:
- .:/usr/local/borrow-a-boat
- ./devenv/api/pythonrc.py:/root/pythonstartup.sh
networks:
- zenet
depends_on:
- "db"
ports:
- "9000:9000"
command:
python3 /usr/local/borrow-a-boat/src/django/abc/manage.py runserver 0.0.0.0:9000
tty: true
volumes:
pgdata:
customboatdata:
networks:
zenet:
(sensitive info has been replaced)
My colleagues have the setup running fine. I setup the app & the volumes & containers are up & running. I can hit the service api at port 9000 fine from browser & confirm that the db is populated. However, my web service is unable to get the data from the api. How can I confirm that the above assertion is correct & that the web really cannot communicate with the api service.
And how can I fix this & get the web to receive the data from api. Apologies for the newbie question.
EDIT:
When I run ping api from within the web container using docker exec -it [containerID] /bin/sh, I am recieving a response in the form of :
64 bytes from 172.18.0.4: seq=139 ttl=64 time=0.084 ms
So, clearly, my assertion is incorrect. Why is web service unable to get a response from api service. When I load the web app in browser, I do not get any log display in the terminal of the api being hit.
EDIT-2 :
As per #runwuf question & my response, clearly, the 'web' is able to communicate with the 'api' service. So, something else is wrong. Here are the steps, we follow to setup the stack on our systems. I use a Linux Mint 19.2 OS, while the team uses Macs. The commands are:
docker kill $(docker_container_names)
docker rm -v $(docker_container_names)
docker volume rm abc_pgdata
docker image rm abc_api
docker image rm abc_web
docker-compose build
docker-compose up -d db api web
ssh abc#abc.com 'pg_dump abc | gzip' | gunzip | docker-compose run --rm db psql --host db --username abc
docker-compose run --rm db psql --host db --username abc -c "update core_photo set image_base = 'sample.jpg'"
docker-compose run --rm db psql --host db --username abc -c "update core_experienceimage set image_base = 'sample.jpg'"

Answer 1

In the end, it was a case of env variable not accessible within web service. All it took was to read the console logs in the browser which showed the undefined variable.
The lesson for me is to when it comes to problem solving, no matter how new the technology, don't forget to use the tools you are familiar with.