How can I run an npm command in a docker container?

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

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 2

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.