how to use ros | cmake with gitlab-ci - c++

Question

I have a simple project but i have no experiences with GitLab-ci. I use ROS and cmake to build my project on my local machine(ubuntu18-04).
now I want to build my project on GitLab but this doesn't look easy for me.
Steps:
1-) installed binary runners from here
2-) registered runners from here for Linux
- used docker as an executor (like gitlabci; i have no experience with docker)
- selected ruby:2.6 default image
3-) Now' i can see my runner under Settings > CI/CD -> Runners
4-) Creating example .yml provided from gitlab
build-job:
stage: build
script:
- echo "Hello, $GITLAB_USER_LOGIN!"
test-job1:
stage: test
script:
- echo "This job tests something"
test-job2:
stage: test
script:
- echo "This job tests something, but takes more time than test-job1."
- echo "After the echo commands complete, it runs the sleep command for 20 seconds"
- echo "which simulates a test that runs 20 seconds longer than test-job1"
- sleep 20
deploy-prod:
stage: deploy
script:
- echo "This job deploys something from the $CI_COMMIT_BRANCH branch."
And its working!
But now I want to build my code on gitlab-ci. File structure:
scripts
->build.sh
src
->Cmakelist.txt
->codes.cpp
binaries
->outputs ll be here.
.gitlab-ci.yml
build.sh doing everything that I want:
...
mkdir build
cd build
cmake .. -GNinja
ninja
So I need just run it. But I don't know how to install prerequisites.
Which system exactly am I working on right now and how can I install prerequisites? (ubuntu 18.04 - docker - runner.. I just got mixed up )

Answer 1

Which system exactly am I working on right now
You clicked selected ruby:2.6 default image so you are on ruby:2.6. You may then browse docker hub : https://hub.docker.com/_/ruby and dockerfile https://github.com/docker-library/ruby/blob/8e49e25b591d4cfa6324b6dada4f16629a1e51ce/2.6/buster/Dockerfile - I see it has "buster" which is the name of one of debian releases, so I guess it's debian.
how can I install prerequisites?
That depends on the image your are using, different linux distributions use different package mangers. I usually take a look at wiki package manager.
You could just something like:
build:
image: ubuntu
script:
- apt-get install -y cmake gcc whatever-else-like-you-have-on-your-machine
- ./scripts/build.sh