Added guide for Deploying Lucky app with Docker

[nicbet]

A guide that describes how to build a docker container image of your Lucky app for deployment. Background: https://gitter.im/luckyframework/Lobby?at=5a67a423e0141226508243c0

[hanneskaeufler]

Cool, I like the intro, I think this will benefit the guides!

[hanneskaeufler]

This will signal to Lucky that it should, for example, display absolute timestamps in the server log, <= I think that bit about the absolute timestamps is uninteresting to most users. Can we rather say something like This will signal to Lucky that it should, for example, use the production database?

[hanneskaeufler]

This will be yarn prod now

[hanneskaeufler]

That might be resolved already? https://github.com/luckyframework/lucky_cli/blob/master/src/web_app_skeleton/src/server.cr

[paulcsmith]

Thanks for writing this @nicbet and thanks for taking a look @hanneskaeufler. I don't have much experience with Docker so I appreciate your input.

[hanneskaeufler]

We could advise to use --release here as well?

[hanneskaeufler]

@nicbet do you think it is reasonable to assume that someone using this guide has already set up his app locally? I am asking because the Dockerfile does not do crystal deps or yarn install. Not saying that is wrong, but I am wondering what the docker-ers (? 🤓) out there are doing. Myself e.g. I am building and running the app in docker (sometimes). Thats why the dockerfile looks more like

FROM hanneskaeufler/crystal-node-ruby

# add application code
ADD . /app
WORKDIR /app

# install app dependencies (crystal)
RUN crystal deps

# install app dependencies (node)
RUN yarn install

# precompile assets (via brunch)
RUN ./bin/compile_assets build --production

RUN crystal build src/server.cr
CMD ./server

I DO think it is a good idea not to go into docker-compose (for database e.g) straight away. Maybe in a tiny section in the end?

[nicbet]

@hanneskaeufler you make a good point. I think the focus of the guide as on deployment via Docker, rather than using a Crystal Docker container as a development environment (which I am doing with pretty much every language myself these days). To develop using a Docker image, you'd have to create a new base image (like you have done with hanneskauefler/crystal-node-ruby) and add all required dependencies (such as node) into the image.

I'm okay with adding an additional section, or perhaps a separate guide.