webwords: a minimal viable web app with docker in as many languages as possible

The companion webwords blog post lives here.

This project shows how to code the same minimal web app called webwords in as many different programming languages as possible. It also provides guides for building and running webwords as a docker image.

Contents

• what is webwords
• why is webwords
• go
• python
• ruby
• js
• debugging

what is webwords

A simple web application whose spec accepts the following two query parameters —

keyword:

The keyword you want to search for.

target:

The URI target that you want to search.

The application always returns an HTTP 200 response with the string true or false depending on if the keyword is found in the target web page body.

For example, to see if the word potato exists on Remarkbox, put the follwing in a browser:

http://127.0.0.1:32779/?keyword=potato&target=https://www.remarkbox.com

Spoiler:

potato does exist on Remarkbox, : )

Note:

You will need to replace the port of 32779 with the port from the docker ps output.

why is webwords

Webwords started as a programming Kata to practice writing code in different programming languages. Each port of webwords should behave the same to make comparing and functional testing simple.

why did you choose this programming problem?

I think the spec of webwords is small enough for people new to any language to digest but complete in that it does something useful and demonstrates two common tasks: running an HTTP server and using an HTTP client.

Also, I needed a way to verify if a user had possession of a domain name for the comment service I'm building and chose to code this verification program as a micro service, first with Python and later with Go. The tiny end result was webwords.

Shortly after, during a company hackathon at Remind I used webwords to learn how to build Docker images for various languages and formalized the idea into a single project.

What's next?

Webwords is for tinkering. If you want to add a version or touch up an existing version, send a PR. Maybe a future fork will show a guide for adding a cache layer or teach how to add logging or gather metrics.

go

To build the docker image:

cd go
docker build -t webwords-go .

To run a test container from the new image:

docker run -d -p 8888 webwords-go

python

To build the docker image:

cd python
docker build -t webwords-python .

To run a test container from the new image:

docker run -d -p 8888 webwords-python

ruby

To build the docker image:

cd ruby
docker build -t webwords-ruby .

To run a test container from the new image:

docker run -d -p 8888 webwords-ruby

js

To build the docker image:

cd js
docker build -t webwords-js .

To run a test container from the new image:

docker run -d -p 8888 webwords-js

debugging

If you're anything like me, your programs rarely compile or work properly on the first try. Just like with programming, a docker image will rarely build correct the first time so you will need to learn how to debug.

To debug, get the failed docker container's id:

docker ps --all

Once you have the id, you can run the following to see the error:

docker logs <container-id>

Debug the issue, fix your Dockerfile, and retry the build process until you have it working.

You can delete old attempts by running:

docker rm <container-id>

You may shell into a container like this:

docker exec -i -t <container-id> /bin/sh