Docker compose missing yarn dependencies on build - docker-compose

Question

Can't get node_modules folder when running yarn install in the Dockerfile
test-sof
├── docker-compose.yml
├── Dockerfile
├── package.json
└── yarn.lock
docker-compose.yml
version: '3'
services:
web:
build: .
volumes:
- .:/myapp
package.json
{
"name": "site",
"private": true,
"dependencies": {
"#rails/webpacker": "^3.2.1",
"babel-preset-react": "^6.24.1",
"prop-types": "^15.6.0",
"react": "^16.2.0",
"react-dom": "^16.2.0",
"reactjs": "^1.0.0",
"underscore": "^1.8.3"
},
"devDependencies": {
"webpack-dev-server": "^2.11.1"
}
}
Dockferfile
FROM ruby:2.5
RUN curl -sL https://deb.nodesource.com/setup_8.x | bash - && \
curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | apt-key add - && \
echo "deb https://dl.yarnpkg.com/debian/ stable main" | tee /etc/apt/sources.list.d/yarn.list && \
apt-get update && \
apt-get install -qq -y build-essential libpq-dev nodejs yarn
RUN mkdir /myapp
WORKDIR /myapp
ADD ./package.json /myapp/
RUN yarn install
output of the step RUN yarn install when docker-compose build:
Step 6/6 : RUN yarn install
---> Running in 3a0e7095ec81
yarn install v1.3.2
info No lockfile found.
[1/4] Resolving packages...
[2/4] Fetching packages...
info fsevents#1.1.3: The platform "linux" is incompatible with this module.
info "fsevents#1.1.3" is an optional dependency and failed compatibility check. Excluding it from installation.
[3/4] Linking dependencies...
warning "#rails/webpacker > postcss-cssnext#3.1.0" has unmet peer dependency "caniuse-lite#^1.0.30000697".
warning " > webpack-dev-server#2.11.1" has unmet peer dependency "webpack#^2.2.0 || ^3.0.0".
warning "webpack-dev-server > webpack-dev-middleware#1.12.2" has unmet peer dependency "webpack#^1.0.0 || ^2.0.0 || ^3.0.0".
[4/4] Building fresh packages...
success Saved lockfile.
Done in 21.11s.
Removing intermediate container 3a0e7095ec81
---> 5720579a0f2a
Successfully built 5720579a0f2a
Successfully tagged testsof_web:latest
Running command: docker-compose run web bash to get in the container
root#11af1818e494:/myapp# ls
Dockerfile docker-compose.yml package.json
no node_modules folder present, but later when running inside the container: yarn install output:
root#11af1818e494:/myapp# yarn install
yarn install v1.3.2
info No lockfile found.
[1/4] Resolving packages...
[2/4] Fetching packages...
info fsevents#1.1.3: The platform "linux" is incompatible with this module.
info "fsevents#1.1.3" is an optional dependency and failed compatibility check. Excluding it from installation.
[3/4] Linking dependencies...
warning "#rails/webpacker > postcss-cssnext#3.1.0" has unmet peer dependency "caniuse-lite#^1.0.30000697".
warning " > webpack-dev-server#2.11.1" has unmet peer dependency "webpack#^2.2.0 || ^3.0.0".
warning "webpack-dev-server > webpack-dev-middleware#1.12.2" has unmet peer dependency "webpack#^1.0.0 || ^2.0.0 || ^3.0.0".
[4/4] Building fresh packages...
success Saved lockfile.
Done in 13.03s.
then when listing:
root#11af1818e494:/myapp# ls
Dockerfile docker-compose.yml node_modules package.json yarn.lock
folder node_modules IT IS present. Why?

Answer 1

This part of Dockerfile installs yarn packages:
RUN mkdir /myapp
WORKDIR /myapp
ADD ./package.json /myapp/
RUN yarn install
Folder /myapp is created, package.json is copied to it and yarn packages are installed. Build is successful and, of course, node_modules folder is inside built image.
But after that you start built image with:
volumes:
- .:/myapp
which means that content of folder where docker-compose.yaml is is mounted to /myapp folder inside container, so it covers content of container's /myapp folder.
You don't need to mount current folder to container's folder to achieve what you want. Just delete it from your docker-compose.yaml:
version: '3'
services:
web:
build: .
Now you can:
$ docker-compose build
$ docker-compose run web bash
root#558d5b0c2ccb:/myapp# ls -la
total 268
drwxr-xr-x 3 root root 4096 Feb 23 22:25 .
drwxr-xr-x 65 root root 4096 Feb 23 22:36 ..
drwxr-xr-x 818 root root 36864 Feb 23 22:25 node_modules
-rw-rw-r-- 1 root root 333 Feb 23 22:07 package.json
-rw-r--r-- 1 root root 219075 Feb 23 22:25 yarn.lock
EDIT:
But what I want is when building the image, get these dependencies not
when spinning up the containers. Otherwise I have another container
which mounts de source code and needs this node_modules folder when
running the "docker-compose up" and I'd like to avoid some kind of
ugly sleep until the node_modules is finished. So I need present this
folder on my root host before up the containers somehow
If you want to achieve the above goal, you can use the following workaround:
1. You modify Dockerfile a little:
FROM ruby:2.5
RUN curl -sL https://deb.nodesource.com/setup_8.x | bash - && \
curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | apt-key add - && \
echo "deb https://dl.yarnpkg.com/debian/ stable main" | tee /etc/apt/sources.list.d/yarn.list && \
apt-get update && \
apt-get install -qq -y build-essential libpq-dev nodejs yarn
RUN mkdir /build && mkdir /myapp
WORKDIR /build
ADD ./package.json /build/
RUN yarn install
WORKDIR /myapp
CMD cp -a /build/node_modules/ /myapp/
That's means that yarn packages will be built in /build folder inside image and copied to /myapp folder once container is started.
2. You use the original docker-compose.yaml file:
version: '3'
services:
web:
build: .
volumes:
- .:/myapp
when you start web container:
docker-compose up web
folder node_modules is copied to mounted folder i.e. to . folder on your host machine.
3. Now you can start any container and it will be contain node_modules folder inside /myapp:
docker-compose run web bash
So, you will be able to achieve your goal the following way:
$ docker-compose build && docker-compose up web
$ docker-compose run web bash
root#4b38e60adfa3:/myapp# ls -la
total 64
drwxrwxr-x 3 1000 1000 4096 Feb 24 10:59 .
drwxr-xr-x 66 root root 4096 Feb 24 11:13 ..
-rw-rw-r-- 1 1000 1000 497 Feb 24 10:55 Dockerfile
-rw-rw-r-- 1 1000 1000 73 Feb 24 09:02 docker-compose.yaml
drwxr-xr-x 818 root root 40960 Feb 24 10:57 node_modules
-rw-rw-r-- 1 root root 333 Feb 23 22:07 package.json