Use github private repo deploy key inside build stage in docker for npm install

Question

My use case is that I have multiple express micro-services that use the same middleware and I would like to create a different repo in the format of an npm module for each m

Answer 1

Let's experiment with this new feature: Docker multi stage build

You can selectively copy artifacts from one stage to another, leaving behind everything you don’t want in the final image.

The idea is to build a temporary base image, then start the build again only taking what you want from the previous image. It uses multiple FROM in the same Dockerfile:

FROM node as base-node-modules
COPY your_secret_key /some/path
COPY package.json /somewhere
RUN npm install <Wich use your key>

FROM node #yes again!
...
...
COPY --from=base-node-modules /somewhere/node_modules /some/place/node_modules
...
... # the rest of your Dockerfile
...

Docker will discard everything what you don't save from the first FROM.