How can I run an npm command in a docker container? - node.js

Question

I am trying to run an angular application in development mode inside a docker container, but when i run it with docker-compose build it works correctly but when i try to put up the container i obtain the below error:
ERROR: for sypgod Cannot start service sypgod: OCI runtime create failed: container_linux.go:346: starting container process caused "exec: \"npm\": executable file not found in $PATH
The real problem is that it doesn't recognize the command npm serve, but why??
The setup would be below:
Docker container (Nginx Reverse proxy -> Angular running in port 4000)
I know that there are better ways of deploying this but at this moment I need this setup for some personals reasons
Dockerfile:
FROM node:10.9
COPY package.json package-lock.json ./
RUN npm ci && mkdir /angular && mv ./node_modules ./angular
WORKDIR /angular
RUN npm install -g #angular/cli
COPY . .
FROM nginx:alpine
COPY toborFront.conf /etc/nginx/conf.d/
EXPOSE 8080
CMD ["nginx", "-g", "daemon off;"]
CMD ["npm", "serve", "--port 4000"]
NginxServerSite
server{
listen 80;
server_name sypgod;
location / {
proxy_read_timeout 5m;
proxy_set_header X-Real-IP $remote_addr;
proxy_pass http://localhost:4000/;
}
}
Docker Compose file(the important part where I have the problem)
sypgod: # The name of the service
container_name: sypgod # Container name
build:
context: ../angular
dockerfile: Dockerfile # Location of our Dockerfile

Answer 1

The image that's finally getting run is this:
FROM nginx:alpine
COPY toborFront.conf /etc/nginx/conf.d/
EXPOSE 8080
CMD ["npm", "serve", "--port 4000"]
The first stage doesn't have any effect (you could COPY --from=... files out of it), and if there are multiple CMDs, only the last one has an effect. Since you're running this in a plain nginx image, there's no npm command, leading to the error you see.
I'd recommend using Node on the host for a live development environment. When you've built and tested your application and are looking to deploy it, then use Docker if that's appropriate. In your Dockerfile, run ng build in the first stage to compile the application to static files, add a COPY --from=... in the second stage to get the built application into the Nginx image, and delete all the CMD lines (nginx has an appropriate default CMD). #VikramJakhar's answer has a more complete Dockerfile showing this.
It looks like you might be trying to run both Nginx and the Angular development server in Docker. If that's your goal, you need to run these in two separate containers. To do this:
Split this Dockerfile into two. Put the CMD ["npm", "serve"] line at the end of the first (Angular-only) Dockerfile.
Add a second block in the docker-compose.yml file to run the second container. The backend npm serve container doesn't need to publish ports:.
Change the host name of the backend server in the Nginx config from localhost to the Docker Compose name of the other container.

Answer 2

It would appear the npm can't be accessed from the container.
Try defining where it tries to execute it from:
docker run -v "$PWD":/usr/src/app -w /usr/src/app node:10.9 npm serve --port 4000
source: https://gist.github.com/ArtemGordinsky/b79ea473e8bc6f67943b
Also make sure that npm is installed on the computer running the docker container.

Answer 3

You can do something like below
### STAGE 1: Build ###
# We label our stage as ‘builder’
FROM node:alpine as builder
RUN apk --no-cache --virtual build-dependencies add \
git \
python \
make \
g++
RUN mkdir -p /ng-app/dist
WORKDIR /ng-app
COPY package.json package-lock.json ./
## Storing node modules on a separate layer will prevent unnecessary npm installs at each build
RUN npm install
COPY . .
## Build the angular app in production mode and store the artifacts in dist folder
RUN npm run ng build -- --prod --output-path=dist
### STAGE 2: Setup ###
FROM nginx:1.14.1-alpine
## Copy our default nginx config
COPY toborFront.conf /etc/nginx/conf.d/
## Remove default nginx website
RUN rm -rf "/usr/share/nginx/html/*"
## From ‘builder’ stage copy over the artifacts in dist folder to default nginx public folder
COPY --from=builder /ng-app/dist /usr/share/nginx/html
CMD ["nginx", "-g", "daemon off;"]

Answer 4

If you have Portainer.io installed for managing your Docker setup, you can open the console for a particular container from a browser.
This is useful if you want to run a reference command like "npm list" to show what versions of dependencies have been loaded.
So that you can view it like this:
I found this useful for diagnosing issues where an update to a dependency had broken something, which worked fine in a test environment, but the docker version had installed newer minor versions which broke the application.