How To Create a CI CD in simple python program

The final project structure would be like this:

For CI CD we need this particular files:
- bin/ansible/project_name.playbook.yml
- hosts -> to list hostname and its IP of destination server
- Dockerfile -> image for the project
- .gitlab-ci.yml -> step to do the CI and CD in yaml format.

First, we create a Dockerfile to run the program. in this case, it would be a python program.

FROM python:3.8.0 AS project_name
ADD requirements.txt /tmp
RUN pip install -r /tmp/requirements.txt
COPY . /opt/project_name
WORKDIR /opt/project_name
ENTRYPOINT ["/opt/project_name/run.sh"]

try to run it manually, whether your program is running well or not. Adjust some configurations until it works perfectly.

$ sudo docker run -it project_name:latest /bin/bash

then push it to the repository. In this case, we use google cloud to store our image.

$ sudo docker tag project_name:latest your_region.gcr.io/your_google_project/project_name:latest
$ sudo docker push your_region.gcr.io/your_google_project/project_name:latest

Created bin directory for ansible deployment:

1. Create playbook

---
- name: deploy project_name scheduler
  hosts: adhoc
  connection: ssh
  tasks:
  - name: Login to your_region.gcr.io
    command: bash -c "cat /home/your_project/.config/your_configuration_file | docker  login -u _json_key --password-stdin your_regio.gcr.io"
  - name: pull image your_project
    docker_image:
      name: your_region.gcr.io/your_google_project/project_name
      source: pull
      repository: your_region.gcr.io/your_google_project/project_name
      force_source: yes
  - name: remove old docker image
    command: bash -c 'docker images your_region.gcr.io/your_google_project/project_name:latest --filter "before=your_region.gcr.io/your_google_project/project_name:latest" -q | xargs docker rmi -f || true'

2. added file called hosts so the gitlab server can refer to your host

[localhost]
localhost
[adhoc]
your_hostname ansible_host=your_host_ip ansible_user=your_host_user

3. create gitlab-ci.yml in root dir of your project. We’re using dind image (docker in docker image). This image is used for creating docker image inside a docker image.

image:
  name: your_region.gcr.io/your_google_project/your_ansible_image
stages:
  - testing
  - build
  - deploy
variables:
  PATH_CREDENTIAL: "/tmp/id_rsa"
  ANSIBLE_HOST_KEY_CHECKING: "false"
before_script:
  - echo "${RSA64_GITLAB_RUNNER}" | base64 -d > ${PATH_CREDENTIAL}
  - chmod 600 ${PATH_CREDENTIAL}
testing:config:
  stage: testing
  variables:
    GCLOUD_CREDENTIAL: /root/gcloud-credential.json
  before_script:
    - echo "${GCLOUD_CREDENTIAL64}" | base64 -d > ${GCLOUD_CREDENTIAL}
  script:
    - echo "TODO:Config Testing"
testing:unit:
  image: your_region.gcr.io/your_google_project/project_name_testing:latest
  stage: testing
  script: 
    - pytest
build:docker:
  image: docker:latest
  stage: build
  services:
    - docker:18.09.7-dind
  variables:
    DOCKER_HOST: tcp://docker:2375/
    DOCKER_DRIVER: overlay2
  tags:
    - dind
  before_script:
    - echo "${GCLOUD_CREDENTIAL64}" | base64 -d | docker login -u _json_key --password-stdin your_region.gcr.io
  script:
    - docker build -t your_region.gcr.io/your_google_project/project_name .
    - docker push your_region.gcr.io/your_google_project/project_name
    - docker logout
    - docker rmi your_region.gcr.io/your_google_project/project_name
  only: 
    - master
deploy:project_name-server:
  image:
    name: your_region.gcr.io/your_google_project/bi-ansible:latest
  stage: deploy
  script: 
    - ansible-playbook -v --inventory=$(pwd)/bin/ansible/hosts --private-key=${PATH_CREDENTIAL} $(pwd)/bin/ansible/project_name.playbook.yml
  only: 
    - master

make sure to put any credential in gitlab ci-cd settings. In this case we used 3 credentials (RSA64_GITLAB_RUNNER, PATH_CREDENTIAL, PATH_CREDENTIAL).

in RSA64_GITLAB_RUNNER we put id_rsa private into the dind docker so it would be able to login into our production machine.