Project Description

The purpose of this project is to demonstrate the DevOps daily routine to manage the entire application development lifecycle, that is: Development, Testing, Deployment, and monitoring.

DevOpsDaily is a simple RESTful API application to provide access to a database of users and performing various actions on it.

For simplicity, the database will be stored as a simple JSON file in the following format:
users.json:

{
    "duncan_long": {
        "id": "drekaner",
        "name": "Duncan Long",
        "favorite_color": "Blue"
    },
    "kelsea_head": {
        "id": "wagshark",
        "name": "Kelsea Head",
        "favorite_color": "Ping"
    },
    "phoenix_knox": {
        "id": "jikininer",
        "name": "Phoenix Knox",
        "favorite_color": "Green"
    },
    "adina_norton": {
        "id": "slimewagner",
        "name": "Adina Norton",
        "favorite_color": "Red"
    }
}

The application exposes 3 endpoints:

• users.json File is stored in JsonPlaceHolder, which will be used as the db server, receiving HTTP get requests from the application.
• The application was built by using the simple Flask web Framework.

---

Containers

Once we have a working application, we should containerize it.
In order to do so, i'll be using Docker Desktop and build a container so users can run the following two commands:

$ docker build -t app:latest /path/to/Dockerfile
$ docker run -d -p 5000:5000 app

to assemble an image I used a Dockerfile as follows:

FROM ubuntu:16.04
RUN apt-get update -y && \
    apt-get install -y python-pip python-dev
# We copy just the requirements.txt first to leverage Docker cache
COPY ./requirements.txt /app/requirements.txt
WORKDIR /app
RUN pip install -r requirements.txt
COPY . /app
ENTRYPOINT [ "python" ]
CMD [ "app.py" ]

Using the docker build command builds an image from a Dockerfile and results as follows:

Using the docker run creates a container from the given image above and starts the container. results as follows:

Now we have the Application containerize and running as a proccess in the Docker.

---

Unit Tests

In the tests stage we should write a simple unit-test for testing the functionality of the application. The unit-test creates a mock JSON database file (users.json) with predefined data, and validate that the application returns the correct information.

For example, given the following input file:

{
    "test_user": {
        "id": "test",
        "name": "Test User",
        "favorite_color": "Black"
    }
}

(Test #1) Accessing the /users URI should return:

{
    "test_user": {
        "name": "Test User",
        "favorite_color": "Black"
    }
}

(Test #2) Accessing the /user/test_user URI should return:

{
    "test_user": {
        "id": "test",
        "name": "Test User",
        "favorite_color": "Black"
    }
}

(Test #3) Accessing the /user/test_user123 URI should return HTTP code 404 as the user does not exist in the database.

• For this stage, I used Pytest framework to test the application functionality.
• For testing with mock JSON database file object, I have used the: unittest.mock library, which allows replacing parts of the system under test with mock objects and making assertions about how they have been used.

---

CI

In the last stage, we have a working app that can also run inside a container, we should setup CI for it, so it won't break in the future. for setting up the CI I have used the following guidelines:

1. Installed and Set up the project in Jenkins +configured required Jenkins Plugins to run Python Unit Test.
2. Clone the application source code from a GitHub repository.
3. Verify the result - run the unit-test and made sure all the tests pass.
4. BONUS: Automatically execute the CI on every new pull request.

For Seting up the project in Jenkins I used "Build a free-style software project" and added a build step "Execute Windows batch command", with the following configuration:

echo '#### create Python3 Virtual Environment ####'
source scl_source enable rh-python36

VIRTUAL_ENV_NAME='virtual-environment'
py -m venv $VIRTUAL_ENV_NAME

echo '#### Avtivate Virtual Environment ####'
source $VIRTUAL_ENV_NAME/bin/activate

echo '#### Install requirments ####'
py -m pip install -r requirements.txt
py -m pip install --upgrade pip

echo '#### Run Tests ####'
py -m pytest --junitxml=test.xml

Configuring GitHub

running all unit-tests from test_application.py and getting Success.

running all unit-tests from test_application.py and getting failure by looking for a user which is exist in the fake database (mock JSON)(Test #3).

© 2020 Tal Mosenzon. All rights reserved.