Ruby Dockerfile 显示用法和选项，而不是启动 rails 服务器

Question

The problem

I have created my own dockerfile to spin up a rails api loosely based on https://docs.docker.com/samples/rails/

Everything builds fine and the image creates successfully but when I start the image I get the output below on how to use the rails command in my Docker logs.

See the following image:

This hasn't given me too much to go on from a debugging aspect so I was curious if anyone had experienced this before. Ill attach my Dockerfile and other related files below for context. For reference API contains my Gemfile.

Associated Files

Dockerfile:

FROM ruby:2.7

WORKDIR /api
COPY /api/ .

RUN bundle install

COPY entrypoint.sh /usr/bin/
RUN chmod +x /usr/bin/entrypoint.sh
RUN ls
ENTRYPOINT ["entrypoint.sh"]
EXPOSE 3000

CMD ["rails", "server", "-b", "0.0.0.0"]

Entrypoint.sh

#!/bin/bash
set -e

# Remove a potentially pre-existing server.pid for Rails.
rm -f /tmp/pids/server.pid

# Then exec the container's main process (what's set as CMD in the Dockerfile).
exec "$@"

Gemfile:

source "https://rubygems.org"
git_source(:github) { |repo| "https://github.com/#{repo}.git" }

ruby "2.7.6"

# Bundle edge Rails instead: gem "rails", github: "rails/rails", branch: "main"
gem "rails", "~> 7.0.3"

# Use postgresql as the database for Active Record
gem "pg", "~> 1.4.1"

# Use the Puma web server [https://github.com/puma/puma]
gem "puma", "~> 5.0"

# Build JSON APIs with ease [https://github.com/rails/jbuilder]
# gem "jbuilder"

# Use Redis adapter to run Action Cable in production
# gem "redis", "~> 4.0"

# Use Kredis to get higher-level data types in Redis [https://github.com/rails/kredis]
# gem "kredis"

# Use Active Model has_secure_password [https://guides.rubyonrails.org/active_model_basics.html#securepassword]
# gem "bcrypt", "~> 3.1.7"

# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem "tzinfo-data", platforms: %i[ mingw mswin x64_mingw jruby ]

# Reduces boot times through caching; required in config/boot.rb
gem "bootsnap", require: false

# Use Active Storage variants [https://guides.rubyonrails.org/active_storage_overview.html#transforming-images]
# gem "image_processing", "~> 1.2"

# Use Rack CORS for handling Cross-Origin Resource Sharing (CORS), making cross-origin AJAX possible
# gem "rack-cors"

group :development, :test do
  # See https://guides.rubyonrails.org/debugging_rails_applications.html#debugging-with-the-debug-gem
  gem "debug", platforms: %i[ mri mingw x64_mingw ]
end

group :development do
  # Speed up commands on slow machines / big apps [https://github.com/rails/spring]
  # gem "spring"
end

I've tried to do my own digging but googling combinations of the above description tend to lead to Docker's base documentation rather than anything useful.

Any assistance would be greatly appreciated. Ill stick around if any follow up/context is needed. Thank you in advance!

Answer 1

Usually such output appears when use rails command in folder that doesn't contain rails project

Looks like problem is here

WORKDIR /api
COPY /api/ .

Usually Dockerfile is located in the root of project

So you need to copy all files from project root to work directory of container

WORKDIR /api
COPY . .

This directives mean that in your container /api folder will contain rails code

And if so, then the command rails server -b 0.0.0.0 will not have to cause such an output in the console