Learning Swagger.io (Part 2)

I recently started studying and experimenting with a few of the current features of Swagger.io.

My next goal was to create a docker container to hold a few Swagger tools.

Since it had been a long time since I last used docker, I refreshed my skills by creating a tiny little Dockerfile which built a container that holds Ubuntu plus one package: iputils-ping.  I then published it to the public Docker Hub registry.

This simple exercise would remind me how to publish a Dockerfile, and allow me to ensure the running docker container's network interface and DNS lookup was working. More importantly, it would also be a starting point for adding the Swagger tools.

Perhaps I should have called this article Docker 101 :-)

Here's what I did...

Create Local Dockerfile and Docker Container

On a linux machine with the Docker Client installed, I created a subdirectory folder named swagger0/ and created this file named Dockerfile.  You are welcome to copy/paste it.

############################################################
# Dockerfile to create a simple sandbox with
# ping installed.
# 
# Build an image
#    docker build --tag swagger0 .
#
# Run an instance
#    docker run -t -i swagger0
#
# Inspect
#    docker images
#    docker ps -a
#
############################################################

# Start with the latest Ubuntu OS
FROM ubuntu

# Apply latest OS updates
RUN apt-get -y update
RUN apt-get -y dist-upgrade
RUN apt-get -y autoremove 

# Install something small 
RUN apt-get -y install iputils-ping  

Next., I cd'd into the directory containing the Dockerfile, and built a docker image from the Dockerfile:

        docker build --tag swagger0 .

I confirmed by showing the list of images:

        docker images

docker images
  REPOSITORY  TAG     IMAGE ID      CREATED        VIRTUAL SIZE
  swagger0    latest  8b00a84ba944  8 minutes ago  161.2 MB
  ubuntu      latest  686477c12982  38 hours ago   120.8 MB

Then I started an instance of the image and SSH'd into it with this command:

        docker run -t -i swagger0

I was able to ping Google, and confirmed this local container and network were alive.

Save Dockerfile

I copied my Dockerfile to a remote/backup location, since I planned to delete the current working directory where it resided.

Publish to Docker Hub

I created a new account, named btfsplk, at https://hub.docker.com/

To prepare my local container for publishing to docker hub, I tagged it with my docker hub account name.

        docker tag 8b00a84ba944 btfsplk/swagger0:latest

The resulting new image appeared in my list:

        docker images

docker images
  REPOSITORY        TAG     IMAGE ID      CREATED         VIRTUAL SIZE
  btfsplk/swagger0  latest  8b00a84ba944  10 minutes ago  161.2 MB
  swagger0          latest  8b00a84ba944  10 minutes ago  161.2 MB
  ubuntu            latest  686477c12982  38 hours ago    120.8 MB

I logged into my new docker hub account

        docker login

For future reference, it told me that it saved my creds in a file:

        /root/.docker/config.json

I uploaded my image to docker hub

        docker push btfsplk/swagger0

To confirm, I deleted all docker artifacts

    docker ps -a
    docker rm  9d8s849t0

    docker images
    docker rmi ab23nskr9 etc etc

And deleted the subdirectory folder on my disk (confirm you have backed-up the Dockerfile from this location!!)

    rm -rf swagger0

Download from Docker Hub

Finally, the acid test:  I downloaded my container from the Docker Hub repository into a clean sandbox directory.

    docker run -i -t btfsplk/swagger0

It found the image, downloaded it, and started it.  I got dumped into an SSH window.  I confirmed ping was installed as expected:

root@4146b58b8956:/# ping www.google.com
PING www.google.com (74.125.138.104) 56(84) bytes of data.
64 bytes from 74.125.138.104: icmp_seq=1 ttl=35 time=48.1 ms
64 bytes from 74.125.138.104: icmp_seq=2 ttl=35 time=48.1 ms

Yay