A Web Server Powered by a Snake, a Bottle and (maybe) a Container

A simple Python "hello world" server that can be run in Docker using Bottle.

Bottle is a fast, simple and lightweight micro web-framework for Python.

The examples are taken from the Bottle tutorials at:

• https://bottlepy.org/docs/dev/ - Hello World
• https://bottlepy.org/docs/dev/stpl.html - Bottle Templates
• https://bottlepy.org/docs/dev/tutorial_app.html - TODO List Application

Quick Start - Run Stand Alone Server

This image exists in the index.docker.io registry already, so you can run it with:

$ pip install -r requirements.txt
$ ./sqlCreate.py
$ ./server.py
$ curl http://0.0.0.0:8080/project/welcome/world
$ <h1>Hello world!</h1>

This will:

• Create an SQL database called dependencyList.db
• Start up a web server at http://0.0.0.0:8080/
• Verify the server over HTTP and return a simple Hello world response.

Summary of Files

The server code is fully contained in server.py and the only dependency is on Bottle (which is specified in requirements.txt)

The /views directory contains some Bottle templates to help with the format of the output of the REST calls (HTML + Python)

sqlCreate.py needs to be just run once in order to create the initial db for the dependency list.

Dockerfile contains everything needed to run the server in a docker container.

Simple End Points

The server has a number of simple end points built in that can be called:

• http://0.0.0.0:8080/project/celebrate/day/your%20name - celebrate an engineer!
• http://0.0.0.0:8080/project/celebrate/v2/day/your%20name - celebrate an engineer using a bottle template
• http://0.0.0.0:8080/project/json/example - return some example JSON

More Complex End Points

It also has a more complex example - a project dependency list backed by an SQL db

• http://0.0.0.0:8080/dependency - list all of the open dependencies
• http://0.0.0.0:8080/dependency/json/1 - show dependency at index 1 in JSON format
• http://0.0.0.0:8080/dependency/json/all - show all dependencies in JSON format
• http://0.0.0.0:8080/dependency/new - add a new dependency

This simple dependency list could be easily improved with edit and remove functionality if you want to try your hand at bottle.

Running the Server in Docker

First build the docker image from the Dockerfile:

$ docker build -t you/your_tag_name /PATH/TO/THIS/REPOSITORY

Then run the newly created image as a container:

$ docker run -d -p 8080 you/your_tag_name

This will map port 8080, which the server is listening on, to a dynamically allocated port on the host. You can see which port by running docker ps:

$ docker ps
CONTAINER ID        IMAGE                                    COMMAND                CREATED             STATUS              PORTS                     NAMES
e9b36d702141        you/your_tag_name:latest   /usr/bin/python /hom   3 seconds ago       Up 2 seconds        0.0.0.0:49173->8080/tcp   kickass_archimedes

This shows that port 8080 on the container is mapped to port 49173 on the host. Thus, assuming curl is installed (if not, run sudo apt-get install curl first), you can do:

$ curl localhost:49173/project/welcome/World
Hello World!

To see the output from the container (i.e. the bottle web server logs) run:

docker attach kickass_archimedes

To login to the container's shell prompt run:

docker exec -i -t kickass_archimedes sh

The docker approach is taken (in part) from https://github.com/joshuaconner/hello-world-docker-bottle