Containerize an application of your choice

[moficodes]

For an exercise lets try to containerize an application.

It could be anything.

Ideally something you wrote. (webapps work best).

[ykoyfman]

@grvcekim @mhrosen Here's a simple Python app that runs a web server on port 8000 and returns Hello, world for all GET requests. Simple exercise could be turn this into a Docker container and run it locally, then in a Kubernetes cluster (cloud or kind).

from http.server import HTTPServer, BaseHTTPRequestHandler

class SimpleHTTPRequestHandler(BaseHTTPRequestHandler):

    def do_GET(self):
        self.send_response(200)
        self.end_headers()
        self.wfile.write(b'Hello, world!')

httpd = HTTPServer(('localhost', 8000), SimpleHTTPRequestHandler)
httpd.serve_forever()

[ykoyfman]

Step 1:

Here's the Python 3 Hello World app - paste this into a file called hello.py in a new (empty) directory.

from http.server import HTTPServer, BaseHTTPRequestHandler

class SimpleHTTPRequestHandler(BaseHTTPRequestHandler):

    def do_GET(self):
        self.send_response(200)
        self.end_headers()
        tuple = self.client_address
        self.wfile.write(b'Hello world to: ')
        self.wfile.write(tuple[0].encode("utf-8"))
        print ("Sent response")

httpd = HTTPServer(('0.0.0.0', 8000), SimpleHTTPRequestHandler)
httpd.serve_forever()

This can be run with python3 hello.py. Then go to localhost:8000 on your browser to verify it works.

Step 2: Dockerize

Stop the Python app if it's still running from Step 1 (Ctrl+C). Create a file called Dockerfile in the same directory as hello.py

from python:3
WORKDIR /usr/src/app
COPY hello.py .
CMD [ "python",  "./hello.py" ]
EXPOSE 8000

Build a docker image:

docker build -t pyhello .

Run the container this way:

docker run -p 8000:8000 pyhello

Verify you can access it on localhost:8000 in your browser - note the IP address - it should not be 127.0.0.1 at this point. All done!