Sass is not found for gulp-ruby-sass within Docker container

Question

I have a web application that uses the gulp-ruby-sass plugin and it runs within a container that installs the sass gem.

This is the Dockerfile:

FROM phusion/passenger-customizable:0.9.19
# Set correct environment variables.
ENV HOME /root
# Use baseimage-docker's init process.
CMD ["/sbin/my_init"]
#   Build system and git.
RUN /pd_build/utilities.sh && \
#   Ruby support.
    /pd_build/ruby-2.3.*.sh && \
#   Node.js and Meteor support.
    /pd_build/nodejs.sh && \
    npm install -g gulp jspm yarn && \
        npm install [email protected] && \
        mv node_modules/phantomjs-prebuilt/lib/phantom/bin/phantomjs /usr/bin && \
        rm -r node_modules && \
#   Clean up APT when done.
    apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
EXPOSE 9000
WORKDIR /var/www/
CMD /bin/bash

This is the bootstrap script file (to bootstrap the application):

#! /bin/bash

bundle install
npm install
jspm install
npm config set bin-links false
npm rebuild node-sass

gulp watch

This is the Gemfile:

source "https://rubygems.org"

gem "sass"

And I launch the container this way:

docker run -it --name web -p 9000:9000 --volume $(pwd):/var/www brainy_web sh bootstrap.sh

The problem is that when the gulp task gulp build-css is executed using docker-compose, it doesn't find the sass gem as it is shown in the log: Gem sass is not installed (complete log here), but when I run the container with bash and execute the bootstrap.sh file everything runs smoothly.

Any thoughts on how to use sass with docker and gulp-ruby-sass?

UPDATE

I found that executing from the outside the gulp task, it doesn't find either:

docker exec web gulp build-css

Answer 1

I found the solution! I followed the advice from @webert-s-lima and in here: https://stackoverflow.com/a/29999734/532912 I just added the -l argument when launching the container. The statement would be like this:

docker run -it --name web -p 9000:9000 --volume $(pwd):/var/www brainy_web /bin/bash -l bootstrap.sh