Python Docker Restful API

This tutorial will explain how to implement simple Restful API in Python Docker using Flask.

Q: What is Flask Python?
Ans:

A Python module that makes it simple to create web applications is called Flask. Its core is compact and simple to extend; it's a microframework that has lots of features, such as url routing and a template engine.

Refer steps to setup and install Docker on Windows

What is virtual environment in Python?

A virtual environment virtualenv is used to create independent, separate virtual environments with their own dependencies for multiple project. It generates a new folder for the new virtual environment which has its own libraries folder, pip, and Python interpreter for the Python version used to activate the environment.

What is Docker?

Docker is a set of platform as a service tools that deliver software in containers using OS-level virtualization. Containers are self-contained, containing their own software, libraries, and configuration files, and communicating with one another via well-defined channels. Docker makes it simple for developers to package, ship, and execute any application as a lightweight, portable, self-contained container that can operate almost anywhere.

Follow the steps listed below to begin the project:

Follow the steps to Install Python and editor.
Create a new virtual environment
Select Python Interpreter
Use new virtual environment for the python project
Activate your new created virtualenv
Install Flask if not available

Create a new file called app.py in the python project with below restful api's.

from flask import Flask, request

app = Flask(__name__)

employees = [{"id": 1, "name": "TechGeekNextUser", "role": "Admin"},
             {"id": 2, "name": "User-2", "role": "Supervisor"}]


@app.get("/employees")
def get_employees():
    return {"employees": employees}


@app.post("/employee")
def create_employee():
    emp_data = request.get_json()
    req_emp = {"name": emp_data["name"], "role": emp_data["role"]}
    employees.append(req_emp)
    return req_emp, 201


@app.get("/employee/<id>")
def get_employee(id):
    for emps in employees:
        if emps["id"] == int(id) :
            return emps
    return {"message": "Employee not found"}, 404

Run python flask example app.py using Flask run command and verify http://127.0.0.1:5003/employees to test api's are working at local.

Verify docker installation by using docker command.

(crudProject) PS D:\PythonCrudExample> docker

Usage:  docker [OPTIONS] COMMAND

A self-sufficient runtime for containers

Options:
      --config string      Location of client config files (default
                           "C:\\Users\\TechGeekNext\\.docker")
  -c, --context string     Name of the context to use to connect to the
                           daemon (overrides DOCKER_HOST env var and
                           default context set with "docker context use")
  -D, --debug              Enable debug mode
  -H, --host list          Daemon socket(s) to connect to
  -l, --log-level string   Set the logging level
                           ("debug"|"info"|"warn"|"error"|"fatal")
                           (default "info")
      --tls                Use TLS; implied by --tlsverify
      --tlscacert string   Trust certs signed only by this CA (default
                           "C:\\Users\\TechGeekNext\\.docker\\ca.pem")
      --tlscert string     Path to TLS certificate file (default
                           "C:\\Users\\TechGeekNext\\.docker\\cert.pem")
      --tlskey string      Path to TLS key file (default
                           "C:\\Users\\TechGeekNext\\.docker\\key.pem")
      --tlsverify          Use TLS and verify the remote
  -v, --version            Print version information and quit

Management Commands:
  builder     Manage builds
  buildx*     Build with BuildKit (Docker Inc., v0.5.1-docker)
  compose*    Docker Compose (Docker Inc., 2.0.0-beta.4)
  config      Manage Docker configs
  container   Manage containers
  context     Manage contexts
  image       Manage images
  manifest    Manage Docker image manifests and manifest lists
  network     Manage networks
  node        Manage Swarm nodes
  plugin      Manage plugins
  scan*       Docker Scan (Docker Inc., v0.8.0)
  secret      Manage Docker secrets
  service     Manage services
  stack       Manage Docker stacks
  swarm       Manage Swarm
  system      Manage Docker
  trust       Manage trust on Docker images
  volume      Manage volumes

Commands:
  attach      Attach local standard input, output, and error streams to a running container
  build       Build an image from a Dockerfile
  commit      Create a new image from a container's changes
  cp          Copy files/folders between a container and the local filesystem
  create      Create a new container
  diff        Inspect changes to files or directories on a container's filesystem
  events      Get real time events from the server
  exec        Run a command in a running container
  export      Export a container's filesystem as a tar archive
  history     Show the history of an image
  images      List images
  import      Import the contents from a tarball to create a filesystem image
  info        Display system-wide information
  inspect     Return low-level information on Docker objects
  kill        Kill one or more running containers
  load        Load an image from a tar archive or STDIN
  login       Log in to a Docker registry
  logout      Log out from a Docker registry
  logs        Fetch the logs of a container
  pause       Pause all processes within one or more containers
  port        List port mappings or a specific mapping for the container
  ps          List containers
  pull        Pull an image or a repository from a registry
  push        Push an image or a repository to a registry
  rename      Rename a container
  restart     Restart one or more containers
  rm          Remove one or more containers
  rmi         Remove one or more images
  run         Run a command in a new container
  save        Save one or more images to a tar archive (streamed to STDOUT by default)
  search      Search the Docker Hub for images
  start       Start one or more stopped containers
  stats       Display a live stream of container(s) resource usage statistics
  stop        Stop one or more running containers
  tag         Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE
  top         Display the running processes of a container
  unpause     Unpause all processes within one or more containers
  update      Update configuration of one or more containers
  version     Show the Docker version information
  wait        Block until one or more containers stop, then print their exit codes

Run 'docker COMMAND --help' for more information on a command.

To get more help with docker, check out our guides at https://docs.docker.com/go/guides/

dockerfile
Create dockerfile file under the root directory of project with the following code.

FROM python:3.10
EXPOSE 5003
WORKDIR /app
RUN pip install flask
COPY . .
CMD ["flask", "run", "--host", "0.0.0.0"]

Docker image will setup the Python (base image) using FROM python:3.10.
Rest APIs will be executed on the port given in EXPOSE 5003.
WORKDIR will create /app directory for the container.
RUN pip install flask to install flask.
The first dot in the COPY .. command represents the source, while the second dot represents the destination. As a result, copy the current directory/project to the /app directory.
The final command is flask run âhost 0.0.0.0 to stat the flask.

Build Docker Image
- Create the docker image as described previously, and the dockerfile is ready to start.
- Give the image the name python-flask-crud-app and run docker build -t python-flask-crud-app . command.
- The full stop at the end of the command indicates that the docker file is in the current directory.
- Run the docker image
  Click on Run to start the docker image.
- Test the Restful Api GET Request http://127.0.0.1:5003/employees.