Add Docker image

[paroxp]

What

We'd like to add a docker image, in order to use the prototype kit as "well known" example application that can be hosted on (in our case) Kubernetes.

We had to work in a Docker argument in order for it to be used by the kit to either disable or enable the data usage sharing.

How to review

• Review code
• Run:
  docker build . -t "govuk-prototype-kit:0.0.$(date +"%s")"
  or
  docker build . -t "govuk-prototype-kit:0.0.$(date +"%s")" --build-arg COLLECT_USAGE_DATA=false
  This will build a Docker image you can run
• Run:
  docker run -p 3000:3000 "govuk-prototype-kit:0.0.$(date +"%s")"
  Make sure the timestamp matches the one from the build step
• You should be able to visit http://localhost:3000/

[joelanman]

@paroxp thanks for this. Can you say a bit more about the user needs for this PR? And is this something that will benefit other teams?

[paroxp]

Sure @joelanman.

In simplest terms:

The user need is being able to deploy prototype-kit based apps to platforms that support running as (Docker) containers. ie. Kubernetes, Docker Swarm, GOV.UK PaaS. As an added bonus it can also allow running the application locally on a laptop without having to install any additional dependencies other than Docker. - Currently Node is required following the npm install.

On the "Build/Run" teams we're investigating future platforms for GDS and many of them are Docker based... we would like to ensure that the prototype kit is well support and easy to deploy and so are using it as an example/hello-world type application to demonstrate what deployments to these platforms can look like.

Hope that helps. Do let me know if you have any other questions or concerns. I am also happy to have an in person chat :)

[aliuk2012]

Again thanks for submitting this. 💯

I have reviewed your PR but could I suggest perhaps adding documentation on how to use the docker version to the readme or under the "advanced" installation pages (https://govuk-prototype-kit.herokuapp.com/docs/install/developer-install-instructions). This is just to make Developers aware that they could just use docker to install and run the prototype kit should they wish too.

[joelanman]

Just chatted to Chris at GDS. Two main things:

• which user groups need Docker support?
• if we add it:
  • we might also need documentation on how to use it
  • it would be good to avoid defining a Node version both here and in package.json

[paroxp]

• Rebased on master
• Documentation added - containing the user groups.

it would be good to avoid defining a Node version both here and in package.json

I know what you mean. However it's not a Node version in the Dockerfile per-se. It's a tagged operating system image with node pre-installed. Conveniently they match the Node versions.

I don't think I will be able to read the version from the package.json and parse it in for the docker build step. We could set it to something like: 8-alpine, carbon-alpine or simply latest (11.2 at a time).

[NickColley]

I think this should probably be false by default

[joelanman]

Does it need a default value? Can we ask users the same as normal?

[NickColley]

I think because heroku bypasses this we've not run into it before, I ran into this same issue trying to get the kit running in Glitch, maybe there's a way we could timeout the question or have an environment variable, or something else to stop the server from stalling.

[paroxp]

When pushing an image to the platform, interactive mod isn't a thing. Nor is by default on local environments.

We considered setting this to false, however we didn't want to step on your toes too much :)

Happy to set it to false.

[NickColley]

This proposal might be able to be simplified now that #697 is merged

[joelanman]

@nataliecarey I'm thinking we close this? Is there a user need for Docker support?