CI/CD pipelines
===============

DevOps
------
DevOps is a technical project method to connect software development and customers but ... what is DevOps?

Research these questions about DevOps:

- When was DevOps invented?
- Why was DevOps developed?
- What professions were brought closer by DevOps

CI/CD
-----

Please read and understand the following questions:

- What does CI stand for?
- What does CD stand for?
- What is the difference between Continuous Delivery?
- What is the difference between Continuous Deployment?

.. important::

    Take 30 minutes to research and answer the questions, then discuss them with your coach.

CI/CD lifecycle
---------------

Research the phases of a CI/CD and draw a CI/CD lifecycle.

.. important::

    Make sure you understand every phases, then discuss them with your coach.

GitLab CI
---------
Our deployments are automated with the Gitlab CI. Have a look at our docs were we explain the usage and :ref:`GitLab CI Guidelines <GitLab CI>`. Make yourself familiar with the Guidelines.


.. important::

    Read through the guidelines, then discuss them with your coach.

Concpet of CI/CD
----------------
These are the most important components of Gitlab CI/CD.

+-----------------+---------------------------------------------------+
| Pipelines       | Structure of the CI/CD process through pipelines. |
+-----------------+---------------------------------------------------+
| CI/CD variables | Reusable variable/key-value pairs.                |
+-----------------+---------------------------------------------------+
| Environments    | Staging, Test, Prod used to deploy applications.  |
+-----------------+---------------------------------------------------+
| Job Artifacts   | Output, reuse Artifacts in/outside of git.        |
+-----------------+---------------------------------------------------+
| Gitlab Runners  | Runners that execute Scripts.                     |
+-----------------+---------------------------------------------------+

Here are the CI/CD `concepts <https://docs.gitlab.com/ee/ci/#concepts>`_ explained in detail.

YAML
----

YAML is the markup language used by Gitlab to interpret the commands in you CI/CD configuration file.

Yaml focuses on Key-Value pairs. The most important aspect about Yaml is the distinction between keyword and value. Usualy formated via a colon:

.. code-block::

    Foo: bar

In this example **Foo** represents the `Key` and **bar** the `value`.

- Take a look to this `site <https://getopentest.org/reference/yaml-primer.html>`_ where YAML is explained.
- Do the first `exercises <https://www.educative.io/courses/introduction-to-yaml/q2qjnY8XkBk>`_ about YAML.

Your first pipeline
-------------------

Now that you have the knowledge about git and CI/CD we'll create our first pipeline:

- Create a repository under the `trainee <https://gitlab.confirm.ch/confirm/trainees>`_ group (Name doesn't matter).
- Pull that repo to your local machine.
- Create a file called `.gitlab-ci.yml <https://docs.gitlab.com/ee/ci/quick_start/#create-a-gitlab-ciyml-file>`_.
- Create a Key/Value list with the keyword `Stages <https://docs.gitlab.com/ee/ci/yaml/#stages>`_.
- Create a simple job with an `echo` command.

As the Values for your Key-Value pair you can set any name. Use a name that includes the usage of the stage (i. e. Use `test` as a name for a stage, if you create multiple jobs that test your code.). Your current Stage block should be similar to this:

.. code-block::

    stages:
        - test
        - int
        - prod