Cypress Docker container does not connect to running server - docker

Question

[ EDIT: I am not deleting the question even if it could be a duplicate of this one, because the original question might be harder to search. In case this were not advisable, please feel free to delete/close. ]
I have this docker-compose:
x-common-postgres-env:
&common-postgres-env
POSTGRES_DB: ${POSTGRES_DB}
POSTGRES_USER: ${POSTGRES_USER}
POSTGRES_PASSWORD: ${POSTGRES_PASSWORD}
POSTGRES_PORT: 5432
x-common-postgres:
&common-postgres
image: postgres:13.4
hostname: postgres
environment:
<< : *common-postgres-env
ports:
- "5432:5432"
healthcheck:
test: ["CMD", "pg_isready", "-U", "${POSTGRES_USER}", "-d", "${POSTGRES_DB}"]
x-common-django:
&common-django
build: .
environment:
&common-django-env
<< : *common-postgres-env
DJANGO_SECRET: ${DJANGO_SECRET}
ALLOWED_HOSTS: ".localhost 127.0.0.1 [::1]"
CORS_ALLOWED_ORIGINS: "http://localhost:8000"
CSRF_TRUSTED_ORIGINS: "http://localhost:8000"
healthcheck:
test: ["CMD", "wget", "-qO", "/dev/null", "http://localhost:8000"]
ports:
- "8000:8000"
services:
db:
<< : *common-postgres
profiles:
- prod
volumes:
- ./data/db:/var/lib/postgresql/data
db-test:
<< : *common-postgres
profiles:
- test
web:
<< : *common-django
profiles:
- prod
command: pdm run python manage.py runserver 0.0.0.0:8000
environment:
<< : *common-django-env
POSTGRES_HOST: db
volumes:
- ./KJ_import:/code/KJ_import
- ./docs:/code/docs
- ./KJ-JS:/code/KJ-JS
- ./static:/code/static
- ./media:/code/media
- ./templates:/code/templates
depends_on:
db:
condition: service_healthy
web-test:
<< : *common-django
profiles:
- test
command: pdm run python manage.py runserver 0.0.0.0:8000
environment:
<< : *common-django-env
POSTGRES_HOST: db-test
depends_on:
db-test:
condition: service_healthy
cypress:
# image: "cypress/included:9.2.0"
profiles:
- test
build:
context: .
dockerfile: Dockerfile.cy
# command: ["--browser", "chrome"]
environment:
CYPRESS_baseUrl: http://localhost:8000/
working_dir: /code/KJ-JS
volumes:
- ./KJ-JS:/code/KJ-JS
- ./media:/code/media
depends_on:
web-test:
condition: service_healthy
This Dockerfile.cy
FROM cypress/included:9.2.0
# WORKDIR /code/KJ-JS
COPY system.conf /etc/dbus-1/system.conf
RUN chmod 644 /etc/dbus-1/system.conf
COPY entrypoint.cy.sh /
ENTRYPOINT ["/bin/sh", "/entrypoint.cy.sh"]
and this entrypoint.cy.sh to activate the Cypress tests:
#!/bin/sh
echo "### Create DBus"
dbus-uuidgen > /var/lib/dbus/machine-id
mkdir -p /var/run/dbus
dbus-daemon --config-file=/usr/share/dbus-1/system.conf --print-address &
# Wait for the D-Bus system bus address to be available
while [ -f /var/run/dbus/system_bus_socket ]; do
sleep 1
done
# Check if the dbus-daemon process is running
if ps -ef | grep -v grep | grep dbus-daemon > /dev/null; then
echo "### D-Bus daemon is running"
else
echo "### D-Bus daemon is not running"
fi
# Check if the D-Bus configuration files are correctly configured
if [ -f /etc/dbus-1/system.conf ]; then
echo "### D-Bus system configuration file is present"
else
echo "### D-Bus system configuration file is missing"
fi
# Make sure that the /var/run/dbus directory exists and is writable by the dbus-daemon process
if [ -d /var/run/dbus ]; then
if [ -w /var/run/dbus ]; then
echo "### /var/run/dbus is writable by the dbus-daemon process"
else
echo "### /var/run/dbus is not writable by the dbus-daemon process"
fi
else
echo "### /var/run/dbus does not exist"
fi
# Remove the /var/run/dbus/pid file if it exists
if [ -f /var/run/dbus/pid ]; then
rm -f /var/run/dbus/pid
echo "### /var/run/dbus/pid file removed"
else
echo "### /var/run/dbus/pid file does not exist"
fi
echo "### Bus active"
cd /code/KJ-JS
cypress run --headed --browser chrome
echo "### after cypress run"
exec "$#"
When I run the docker compose --profile test up, the db spins well, django gets up and running, but Cypress cannot seem to connect.
It complained of not having Dbus running, so I added it in the entrypoint shown above, and tested all of its components, yet the error message still comes up:
kj_import-web-test-1 | System check identified no issues (0 silenced).
kj_import-web-test-1 | December 28, 2022 - 02:32:40
kj_import-web-test-1 | Django version 2.2.28, using settings 'KJ_import.settings'
kj_import-web-test-1 | Starting development server at http://0.0.0.0:8000/
kj_import-web-test-1 | Quit the server with CONTROL-C.
kj_import-web-test-1 | [28/Dec/2022 02:32:42] "GET / HTTP/1.1" 200 5776
kj_import-web-test-1 | [28/Dec/2022 02:32:42] "GET /static/favicon.ico HTTP/1.1" 200 9662
kj_import-web-test-1 | [28/Dec/2022 02:32:46] "GET /docs/register/ HTTP/1.1" 200 6551
kj_import-web-test-1 | [28/Dec/2022 02:32:49] "GET / HTTP/1.1" 200 5776
kj_import-web-test-1 | [28/Dec/2022 02:33:02] "GET / HTTP/1.1" 200 5776
kj_import-cypress-1 | ### Create DBus
kj_import-cypress-1 | ### D-Bus daemon is running
kj_import-cypress-1 | ### D-Bus system configuration file is present
kj_import-cypress-1 | ### /var/run/dbus is writable by the dbus-daemon process
kj_import-cypress-1 | ### /var/run/dbus/pid file does not exist
kj_import-cypress-1 | ### Bus active
kj_import-cypress-1 | unix:path=/var/run/dbus/system_bus_socket,guid=1181acd37ea51796e63af6a863ab9ccf
kj_import-cypress-1 | [26:1228/013304.773071:ERROR:bus.cc(392)] Failed to connect to the bus: Address does not contain a colon
kj_import-cypress-1 | [26:1228/013304.773122:ERROR:bus.cc(392)] Failed to connect to the bus: Address does not contain a colon
kj_import-cypress-1 | [213:1228/013304.794142:ERROR:gpu_init.cc(453)] Passthrough is not supported, GL is swiftshader, ANGLE is
kj_import-cypress-1 | Cypress could not verify that this server is running:
kj_import-cypress-1 |
kj_import-cypress-1 | > http://localhost:8000/
kj_import-cypress-1 |
kj_import-cypress-1 | We are verifying this server because it has been configured as your `baseUrl`.
kj_import-cypress-1 |
kj_import-cypress-1 | Cypress automatically waits until your server is accessible before running tests.
kj_import-cypress-1 |
kj_import-cypress-1 | We will try connecting to it 3 more times...
kj_import-cypress-1 | We will try connecting to it 2 more times...
kj_import-cypress-1 | We will try connecting to it 1 more time...
kj_import-cypress-1 |
kj_import-cypress-1 | Cypress failed to verify that your server is running.
kj_import-cypress-1 |
kj_import-cypress-1 | Please start this server and then run Cypress again.
kj_import-cypress-1 | ### after cypress run
kj_import-cypress-1 exited with code 0
kj_import-web-test-1 | [28/Dec/2022 02:33:32] "GET / HTTP/1.1" 200 5776
kj_import-web-test-1 | [28/Dec/2022 02:34:02] "GET / HTTP/1.1" 200 5776
kj_import-web-test-1 | [28/Dec/2022 02:34:32] "GET / HTTP/1.1" 200 5776
Please note that the server is running fine. You can see it from the above log (GETs replied with 200, even before the Cypress container starts trying to connect) and I can access it from my local browser.
What am I missing here?
Thanks in advance!

Answer 1

In the end it was probably pretty simple: localhost in a container refers only to the container itself, not to the host.
This answer pointed me in the right direction.
So, in order to properly instruct Cypress to watch/test the service, the url (CYPRESS_baseUrl inside the docker-compose.yml) that needs to be passed in is in the format http://[service-name]:[port], which in my case was http://web-test:8000/
Be aware that:
also the Cypress tests need to be directed there, and most likely
the ALLOWED_HOSTS will need to include the service-name
PS: There might have been also a second issue at play: in my search I found this reported bug and several comments pointed to the cypress/included:9.2.0 image as potentially affected. I decided to move onto the 9.7.0