Container_from_Code

I will provide a few examples of how to take existing code and make it run in a container.

Note: please keep in mind, my primary "persona" has not been "a developer". I am very much focused on infrastructure and core-services. So, my perspective and approach at analysis and problem solving may look a bit unorthodox.

Create a Python Container running python http.server and JS/HTML5 (HexGL) App.

Python container to run JS App

Description

I have been using the HexGL App to run demos for a few years now. I have used this app through several iterations:

• First running/hosting on a "typical" Apache webserver
• following the author's example of using Python to test
• (I then forked the project to adapt for my own needs)
• Updated to run in Red Hat OpenShift
• run as a simple local container (what this repo is about)

Sources

HexGL Homepage
HexGL GitHub
My HexGL GitHub

Let's roll...

I reviewed BKcore's source on Github to determine what "type of app" I was working with. I see some *.js files... some *.webapp - and then I look at how he suggests you run the app;

cd ~/
git clone git://github.com/BKcore/HexGL.git
cd HexGL
python -m SimpleHTTPServer
chromium index.html

ah - so I just need a webserver. Cool. (note: I am running Fedora 37 which has "chromium-browser" - which you will see in my overview)

Create a docker file (Dockerfile)

So - since I don't actually know what I am doing, I started by using the latest python (which is python3). And the resulting change - instead of running "SimpleHTTPServer - we will run http.server.

Create a "Dockerfile" example Dockerfile

FROM python:latest

LABEL description="HexGL Container Image"
LABEL version="1.0"
LABEL maintainer="knowbettercloud@gmail.com"

#CMD mkdir -p /var/www/html
WORKDIR /var/www/html
# COPY * /var/www/html/
COPY . /var/www/html/

# At Build Time
RUN echo "Note: App will be exposed on port: 8000"
# At Run Time
CMD echo "Note: App will be exposed on port: 8000"
EXPOSE 8000

#CMD python -m http.server 8000
CMD [ "python","-m","http.server","8000"]

Build a Container

mkdir ~/Projects; cd $_
git clone https://github.com/knowbettercloud/HexGL.git
cd HexGL
podman build -t my-hexgl .
podman run -p 8000:8000 --name hexgl localhost/my-hexgl

Or.. Docker, if you prefer

mkdir ~/Projects; cd $_
git clone https://github.com/knowbettercloud/HexGL.git
cd HexGL
docker build -t my-hexgl .
docker run -p 8000:8000 --name hexgl my-hexgl

Then, in another terminal window, run:

chromium-browser http://localhost:8000/index.html

To "enter" the pod to review the content

podman exec -it hexgl /bin/bash
podman logs -f (pod number)

To "reset"

docker kill $(docker ps -a | grep hexgl | awk '{ print $1 }')
docker rm $(docker ps -a | grep hexgl | awk '{ print $1 }')

podman images prune

as an example, check this out

podman run -p 8081:80 acantril/containerofcats

You may need to run chromium to get it working (I think because of permissions, supportability, etc..)

chromium-browser http://localhost:8081/index.html

Optimization (peeping around corners)

To quote one of my favorite old school rap artists... "I keep looking over my shoulder and peeping around corners"

storyline: While troubleshooting my erroneous "COPY syntax" - I discovered that the "python:latest" image was 956MB. Whoa! So - I did some research and discoverd a mention of "3.8.2-slim-buster" - hmm.. let's give it a shot.

Updated my Dockerfile from

FROM python:latest

to

FROM python:3.9-slim-buster

and it seems to (still) work. #solid