Docker Basics for Rails Discussion
Hey Chris, when I downloaded the Source Code GitHub repo and ran docker-compose up, it couldn't build sqlite3.
I tried adding a dependency for sqlite-dev in the Dockerfile, then it worked.
I opened a corresponding PR in your repo to add the dependency.
Great episode! I already use Docker for local development and I love it. Are you planning to do an episode to explain how to deploy a dockerized rails application? It seems very obscure to me.
Thanks for the great tutorial! I am a beginner in dockerizing rails app and get started with this tutorial. I realized some optimization may have been omitted to keep the tutorial concise. Following are some optimization tricks I found useful if starting from the Dockerfile :)
Add (at least)
node_modulesand.gitinto a.dockerignorefile, so theCOPY . /app/step could skip these files. (This could save you a log of time/docker image size when .git is huge)Avoid the error: 'A server is already running. Check /project/tmp/pids/server.pid. Exiting' with an
entrypoint.shscript.
Refer to Docker docs - Sample applications - Rails and PostgreSQL for the complete script, and don't forget to change#!/bin/bashto#!/bin/shsince we are using Alpine in this tutorial.Avoid needing to run
yarn installagain after change the source code and re-build image.
Instead of:
COPY . /app/
ENV BUNDLE_PATH /gems
RUN yarn install
RUN bundle install
do:
ENV BUNDLE_PATH /gems
COPY package.json yarn.lock /app/
RUN yarn install
COPY Gemfile Gemfile.lock /app/
RUN bundle install
# Steps above could be cached most of the time when re-building image
# Copy source code after dependencies installed
COPY . /app/
I'm using this solution and it save a lot of time.
I strongly encourage using this technique with Selective disable caching
http://dev.im-bot.com/docker-select-caching/
So you can put this step befor copy your source code from local to image
This is great, please more docker + rails tutorials. I would like to see how to not re-install all gems if you rebuild the image but have not changed the Gemfile at all.
I agree with Drazen. More Docker+Rails tutorials. Especially on how to deploy to production. Also, how to add sidekiq.
Second this! Probably needs to be tweaked but here's my docker-compose.yml that currently works for local dev with sidekiq
services:
postgres:
image: postgres:10.4-alpine
env_file:
- ./env/common.env
- ./env/dev.env
ports:
- 5432:5432
volumes:
- postgres:/var/lib/postgresql/data
redis:
image: redis:4.0-alpine
ports:
- 6379:6379
volumes:
- redis:/data
app: &app_base
build:
context: .
args:
- BUNDLE_WITHOUT=production
env_file:
- ./env/common.env
- ./env/dev.env
command: bundle exec puma -C config/puma.rb
ports:
- 3000:3000
volumes:
- .:/app
depends_on:
- postgres
- redis
stdin_open: true
tty: true
sidekiq:
<<: *app_base
command: bundle exec sidekiq -C config/sidekiq.yml
ports: []
stdin_open: false
tty: false
volumes:
redis:
postgres:
Note - in the docker file you can't have the last 2 lines of the tutorial triggering rails s
What if I have a windows computer and dont want to install ruby on the computer. Can I create a docker environment that has ruby and rails installed and where I do all the development, editing, rails new inside the image. Even run vscode outside and ssh into the image. Is that possible, and do you have a pointer for an article of yours or elsewhere to help me set that up?
You can make docker-compose create the project for you if you already have defined a Dockerfile and a docker-compose.yml:
docker-compose run --no-deps web rails new . --force --database=postgresql
See more at https://docs.docker.com/samples/rails/#build-the-project
Sweet thanks for the tutorial.
Does anyone know how to deploy AN UPDATE to your rails app: for example, I've made some bug fixes.
I want to deploy these change to an already running docker container hosted on a Digital Ocean droplet.
Any ideas?
Note to others, running Rails 7.0.4.1 with dartsass-rails for your SASS compiling, you may run into segmentation violation (SEGV) errors when running the dartsass:watch command in your Procfile.dev (valled via bin/dev by default in Rails 7+) on ALPINE Linux base images.
I tested on the standard ruby:3.1.2 vs ruby:3.1.2-alpine, and the standard image works fine but Alpine has SEGV errors. Not sure if there's an Alpine dependency that's missing that may resolve, but since I was working on local development, I didn't investigate too much and just went with the base ruby:3.1.2 image. Maybe I'll circle back once the Rails 7.1+ updates implement a default Docker setup, hopefully some folks more knowledgeable about Docker and images have resolved it for us all :)
I had to fork & tweak this a little to get it running on my M1 Mac, I'll post the repo link here once I think its usable for others.
Nice video. Coming back to docker after a couple years and you did a great job explaining what matters for rails setups.