Docker compose is failing when copying npmrc - docker

Question

I am getting this error when trying to run my docker with docker compose
=> ERROR [6/9] COPY .npmrc .npmrc
0.0s => ERROR [7/9] ADD package.json /Users/gs/Documents/Dev/DockerDi 0.0s
version: "3"
services:
gs-service:
build:
context: .
dockerfile: ./gs/Dockerfile
ports:
- 8081:8081
ui-service:
build:
context: .
dockerfile: ./ui/Dockerfile
ports:
- 8083:8083
Here is the detail of the Dockerfile which is failing. This is a subdirectory. For example /user/gs/dockerexperiment/ui
docker-compose file is in parent directory. For example
/user/gs/dockerexperiment
Dockerfile is in subdirectory. For example
/user/gs/dockerexperiment/ui
I know something is going wrong with the class path but I am having a difficult time figuring out what I am missing

Answer 1

A Dockerfile operates on a build context; this is a copy of the directory tree you name as the build: { context: } in the docker-compose.yml file (or, if you're using docker build directly, its directory argument).
build:
context: .
In the Dockerfile, any COPY (or ADD) instructions are interpreted as relative to this directory tree. (If it looks like an absolute path, it's still relative to this directory; any .. path steps that would step outside this directory get ignored.)
COPY package*.json ./
# copies ./package.json, relative to the context directory
But, you clarify in a comment, this isn't actually where your files are. Relative to the docker-compose.yml file, you need ./ui/package.json; the Dockerfile is also in the same subdirectory.
The Dockerfile you show doesn't seem to need any content from outside its immediate tree, so the easiest way to address this is to set the ui directory as the build context:
version: '3.8'
services:
ui:
build: ./ui
# Same as
# build:
# context: ./ui
# dockerfile: Dockerfile # relative to the context directory
ports:
- 8085:8085
In the Dockerfile, you can remove the duplicate ADD package.json line, and you should remove the dangerous RUN npm set config line. You can also set a much shorter WORKDIR, something like /app would be typical.
If you don't want to change the docker-compose.yml file, the other possible change is to adjust the Dockerfile so that its COPY paths are relative to the (parent) build-context directory.
COPY ui/package*.json .
The advantage of doing this is that you can access files from the other application, if you need to, or you can store shared files in that parent directory.
FROM node:14
# Add the public TLS key for our internal repository
# (from the parent directory)
COPY repository.example.com.crt /usr/local/share/ca-certificates
RUN update-ca-certificates
WORKDIR /app
# Also get our local npm configuration (from the parent directory)
COPY .npmrc .
# Install the ./ui application
COPY ui/package*.json .
RUN npm ci
COPY ui/src ./src
EXPOSE 8085
CMD ["npm", "start"]