A simply marvelous toy HTTP server in Go with Docker

This shows how to build a simple go HTTP server inside a Docker container, which can then be used to deploy Google Compute Engine or AWS's Fargate. Useful as a small-footprint example for testing.

Build the image

The -t option gives docker way to refer to your image via 'repository:tag', which is mostly an arbitrary string. The --platform option tells Docker what type of CPU we plan to run this image on. It's important for most deployments that it matches the architecture of the underlying hardware.

$ docker build -t sbeam/simply_marvelous:1.0-amd64 --platform linux/amd64 .
...
=> exporting to image                                                                           1.7s
=> exporting layers                                                                             1.5s
=> writing image sha256:396afd8d10aeb7c71a1bbdf18b83c576ef79805768daf3114c5f633cfc4c7ed7        0.0s
=> naming to docker.io/sbeam/simply_marvelous:1.0-amd64                                         0.0s

Check the images is now known to your local docker daemon

docker images lists all the images currently installed on your system.

$ docker images | head
REPOSITORY                                                   TAG                         IMAGE ID       CREATED          SIZE
sbeam/simply_marvelous                                       1.0-amd64                   396afd8d10ae   35 seconds ago   308MB
...

Run the image, for testing and fun

docker run tells docker to fetch the given image (if not already installed), create a runnable container from it, and then exectute whatever command was given in the CMD instruction in the Dockerfile inside the container.

--rm tells Docker to remove the container after it exits. This prevents a lot of unused containers from building up on your system.
--it tells Docker to start a terminal (TTY) in the running container, and make it interactive, so you can interact with the command running inside the container via your command line on the host.
-p 9999:80 binds the port on your local host to the container's port 80

Note I get a warning about the platform because I'm running this on Apple silicon. (wait, how does Docker translate x86 instructions to ARM? Magic!)

$ docker run --rm -it -p 9999:80 sbeam/simply_marvelous:1.0-amd64
WARNING: The requested image's platform (linux/amd64) does not match the detected host platform (linux/arm64/v8) and no specific platform was requested
2021/07/07 18:44:56 serving on port 80

in another terminal window, use curl, a common command line utility that will make web requests:

$ curl http://localhost:9999/hi
Simply Marvelous, Darling!
$ curl http://localhost:9999/echo/isanyonethere
isanyonethere
$ curl http://localhost:9999/more
1
$ curl http://localhost:9999/more
2

You should see corresponding log output in the window where you started the server.

sbeam/simply_marvelous

A simply marvelous toy HTTP server in Go with Docker

Build the image

Check the images is now known to your local docker daemon

Run the image, for testing and fun

Deploying to AWS Fargate with Terraform

Deploying to Google Compute Engine with Terraform