I am playing around with docker and have seem to run into this permission issue. I started off with the boilerplate react app and am trying map changes to the source code (on my computer, ie host) onto my containers, so that I see the updates instantly. So I dont have to build my image and create containers again and again. If I do build everything from scratch again things works great with no permission issue.
Here's my dockerfile
FROM node:14.17.5-alpine3.14
RUN addgroup app && adduser -S -G app app
# creating folders first to avoid permission issues
RUN mkdir /app
# directory to map a volume
RUN mkdir /app/data
# changing folder permissions
RUN chown -R app:app /app
# Set app as user AFTER setting permissions
USER app
WORKDIR /app
# Copy and install separtely to speed up builds
COPY --chown=app:app package*.json yarn.lock ./
RUN yarn install
# Copy (& also give owner rights to the current user probably unnecessary)
COPY --chown=app:app . .
# the env var is unnecessary, just for testing
ENV API_URL=http://api.myapp.com/
EXPOSE 3000
CMD ["yarn", "start"]
Then I build my image and create my container as below which works as expected. With user app being the owner and having right permissions. Everything is great when I access localhost:5002
# create container but I don't map host to container
docker run -d -p 5002:3000 --name not-mapped-container dockerized-react-app
# run interactive shell
sudo docker exec -it <container_id/name> sh
# from inside container's shell I list the files
# and everything is what I expect
/app $ ls -l
total 528
-rw-rw-r-- 1 app app 664 Aug 20 15:45 Dockerfile
-rw-r--r-- 1 app app 3362 Aug 19 19:14 README.md
drwxr-xr-x 1 app app 4096 Aug 20 15:45 data
drwxr-xr-x 1 app app 4096 Aug 20 17:27 node_modules
-rw-rw-r-- 1 app app 824 Aug 19 19:14 package.json
drwxrwxr-x 2 app app 4096 Aug 19 19:14 public
drwxrwxr-x 2 app app 4096 Aug 19 19:14 src
-rw-rw-r-- 1 app app 510089 Aug 19 19:14 yarn.lock
But now if I do pretty much the exact same thing, but try and map host to containers. Things are not as expected and the owner of the directory is the user node and not app (the set user according to my dockerfile). Now when I go to localhost:8080, I get the following permission issue EACCES: permission denied, mkdir '/app/node_modules/.cache'
# The only change, trying to map host with containers for instant updates
docker run -d -p 8080:3000 --name mapped-container -v $(pwd):/app dockerized-react-app
# run interactive shell again
sudo docker exec -it <container_id/name> sh
# list the files again but now the owner is node
/app $ ls -l
total 556
-rw-rw-r-- 1 node node 664 Aug 20 15:45 Dockerfile
-rw-r--r-- 1 node node 3362 Aug 19 19:14 README.md
drwxrwxr-x 1047 node node 36864 Aug 19 19:14 node_modules
-rw-rw-r-- 1 node node 824 Aug 19 19:14 package.json
drwxrwxr-x 2 node node 4096 Aug 19 19:14 public
drwxrwxr-x 2 node node 4096 Aug 19 19:14 src
-rw-rw-r-- 1 node node 510089 Aug 19 19:14 yarn.lock
So why does this happen? Am I not correctly mapping source code on host to the container or is it something else?
