Welcome to your CDK Python project for Sprint 6!

Technologies used:

• Flask
• ECR
• ECS
• Fargate
• Docker
• Images

The cdk.json file tells the CDK Toolkit how to execute your app.

This project is set up like a standard Python project. The initialization process also creates a virtualenv within this project, stored under the .venv directory. To create the virtualenv it assumes that there is a python3 (or python for Windows) executable in your path with access to the venv package. If for any reason the automatic creation of the virtualenv fails, you can create the virtualenv manually.

To manually create a virtualenv on MacOS and Linux:

$ python3 -m venv .venv

After the init process completes and the virtualenv is created, you can use the following step to activate your virtualenv.

$ source .venv/bin/activate

If you are a Windows platform, you would activate the virtualenv like this:

% .venv\Scripts\activate.bat

Once the virtualenv is activated, you can install the required dependencies.

$ pip install -r requirements.txt

At this point you can now synthesize the CloudFormation template for this code.

$ cdk synth

To add additional dependencies, for example other CDK libraries, just add them to your setup.py file and rerun the pip install -r requirements.txt command.

Useful commands

• cdk ls list all stacks in the app
• cdk synth emits the synthesized CloudFormation template
• cdk deploy deploy this stack to your default AWS account/region
• cdk diff compare deployed stack with current state
• cdk docs open CDK documentation

Docker Commands

• docker ps current containers
• docker run create and start the container
• docker create create container
• dokcer exec to run commnads in container for once
• docker volume create a docker volume
• docker network create a docker network
• docker rm remove container
• docker images list the images
• docker rmi remove image
• docker build build a new image from dockerfile
• docker push push your image to docker repo
• docker pull download an image from docker repo
• docker commit create an image from container

Flask

Flask is a lightweight WSGI_ web application framework. It is designed to make getting started quick and easy, with the ability to scale up to complex applications. It began as a simple wrapper around Werkzeug_ and Jinja_ and has become one of the most popular Python web application frameworks.

Flask offers suggestions, but doesn't enforce any dependencies or project layout. It is up to the developer to choose the tools and libraries they want to use. There are many extensions provided by the community that make adding new functionality easy.

.. _WSGI: https://wsgi.readthedocs.io/ .. _Werkzeug: https://werkzeug.palletsprojects.com/ .. _Jinja: https://jinja.palletsprojects.com/

Installing

Install and update using pip_:

.. code-block:: text

$ pip install -U Flask

.. _pip: https://pip.pypa.io/en/stable/getting-started/

A Simple Example

.. code-block:: python

# save this as app.py
from flask import Flask

app = Flask(__name__)

@app.route("/")
def hello():
    return "Hello, World!"

.. code-block:: text

$ flask run
  * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)

Enjoy!