docker build + private NPM (+ private docker hub)

Question

I have an application which runs in a Docker container. It requires some private modules from the company's private NPM registry (Sinopia), and accessing these requires user authentication. The Dockerfile is FROM iojs:latest.

I have tried:

1) creating an .npmrc file in the project root, this actually makes no difference and npm seems to ignore it 2) using env variables for NPM_CONFIG_REGISTRY, NPM_CONFIG_USER etc., but the user doesn't log in.

Essentially, I seem to have no way of authenticating the user within the docker build process. I was hoping that someone might have run into this problem already (seems like an obvious enough issue) and would have a good way of solving it.

(To top it off, I'm using Automated Builds on Docker Hub (triggered on push) so that our servers can access a private Docker registry with the prebuilt images.)

Are there good ways of either: 1) injecting credentials for NPM at build time (so I don't have to commit credentials to my Dockerfile) OR 2) doing this another way that I haven't thought of ?

Answer 1

In 2020 we've got BuildKit available. You don't have to pass secrets via COPY or ENV anymore, as it's not considered safe.

Sample Dockerfile:

# syntax=docker/dockerfile:experimental
FROM node:13-alpine

WORKDIR /app

COPY package.json yarn.lock ./

RUN --mount=type=ssh --mount=type=secret,id=npmrc,dst=$HOME/.npmrc \
  yarn install --production --ignore-optional --frozen-lockfile

# More stuff...

Then, your build command can look like this:

docker build --no-cache --progress=plain --secret id=npmrc,src=/path-to/.npmrc .

For more details, check out: https://docs.docker.com/develop/develop-images/build_enhancements/#new-docker-build-secret-information

Answer 2

For those who are finding this article via google and are still looking for an alternative way that doesn't involve leaving you private npm tokens on your docker images and containers:

We were able to get this working by doing the npm install prior to the docker build (By doing this it lets you have your .npmrc outside of your image\container). Once the private modules have been installed locally you can copy your files across to the image as part of your build:

    # Make sure the node_modules contain only the production modules when building this image
    COPY . /usr/src/app

You also need to make sure that your .dockerignore file doesn't exclude the node_modules folder.

Once you have the folder copied into your image, the trick is to to npm rebuild instead of npm install. This will rebuild any native dependancies that are effected by any differences between your build server and your docker OS:

    FROM nodesource/vivid:LTS

    # For application location, default from nodesource is /usr/src/app
    # Make sure the node_modules contain only the production modules when building this image
    COPY . /usr/src/app
    WORKDIR /usr/src/app
    RUN npm rebuild
    CMD npm start

Answer 3

I would recommend not using a .npmrc file but instead use npm config set. This works like a charm and is much cleaner:

ARG AUTH_TOKEN_PRIVATE_REGISTRY

FROM node:latest

ARG AUTH_TOKEN_PRIVATE_REGISTRY
ENV AUTH_TOKEN_PRIVATE_REGISTRY=${AUTH_TOKEN_PRIVATE_REGISTRY}

WORKDIR /home/usr/app

RUN npm config set @my-scope:registry https://my.private.registry && npm config set '//my.private.registry/:_authToken' ${AUTH_TOKEN_PRIVATE_REGISTRY}

RUN npm ci

CMD ["bash"]

Answer 4

The buildkit answer is correct, except it runs everything as root which is considered a bad security practice.

Here's a Dockerfile that works and uses the correct user node as the node Dockerfile sets up. Note the secret mount has the uid parameter set, otherwise it mounts as root which user node can't read. Note also the correct COPY commands that chown to user:group of node:node

FROM node:12-alpine

USER node

WORKDIR /home/node/app

COPY --chown=node:node package*.json ./

RUN --mount=type=secret,id=npm,target=./.npmrc,uid=1000 npm ci

COPY --chown=node:node index.js .

COPY --chown=node:node src ./src

CMD [ "node", "index.js" ]