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Docker For Rails Developers - Chapter 2 Defining Our First Custom Image WORKDIR Correctoin

Travis

Travis

Docker For Rails Developers - Chapter 2 Defining Our First Custom Image WORKDIR Correctoin

Dockerfile:

FROM ruby:2.6

RUN apt-get update -yqq
RUN apt-get install -yqq --no-install-recommends nodejs

COPY . /usr/src/app/

WORKDIR /usr/src/app/

RUN bundle install

The Dockerfile instructs us to copy the current directory into /usr/src/app/. Placing our directory myapp into /usr/src/app/.

Then the WORKDIR is defined as /usr/src/app/

And RUN bundle install.

This fails as bundle install should be run in the app directory. We’re in /usr/src/app/ but we should be in /usr/src/app/myapp.

The Dockerfile is corrected with

FROM ruby:2.6

RUN apt-get update -yqq
RUN apt-get install -yqq --no-install-recommends nodejs

COPY . /usr/src/app/

WORKDIR /usr/src/app/myapp

RUN bundle install
4 comments
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Travis

Travis

I ended up with a different solution and believe my original problem was a wrong file structure.

My Dockerfile is now located in the Rails app - myapp. The value of WORKDIR is /usr/src/app/.

Is that how you have yours now?

2
Post #3
jetsondavis

jetsondavis

I made the change you suggest, now get this:
/usr/local/bundle/gems/webpacker-4.3.0/lib/webpacker/configuration.rb:95:in `rescue in load’: Webpacker configuration file not found /usr/src/app/config/webpacker.yml. Please run rails webpacker:install Error: No such file or directory @ rb_sysopen - /usr/src/app/config/webpacker.yml (RuntimeError)

Can anyone help? Frustrating to pay so much for a book that is incorrect.

1
Post #2
edruder

edruder

  • myapp should be your current directory. (cd myapp)
  • The Dockerfile should be created in the myapp directory–it looks like you created it one directory above.
  • docker build . will then succeed, I think.
1
Post #4

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