Nodejs - cannot find module (Docker)-CodePudding

Trying to test out multistage builds in Docker for my nodejs app and I keep running into

internal/modules/cjs/loader.js:983
  throw err;
  ^

Error: Cannot find module '/service/dist/server/server.js'
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:980:15)
    at Function.Module._load (internal/modules/cjs/loader.js:862:27)
    at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:74:12)
    at internal/main/run_main_module.js:18:47 {
  code: 'MODULE_NOT_FOUND',
  requireStack: []
}

My Dockerfile

FROM mybaseimage as dev
WORKDIR /service

COPY src ./src
COPY package*.json ./
COPY yarn.lock ./
COPY tsconfig.json ./

# This is required to build native modules
# https://github.com/nodejs/docker-node/blob/main/docs/BestPractices.md#node-gyp-alpine
RUN apk add --no-cache \
    g   \
    make \
    py3-pip

# Not clearing the cache here saves us time in the next step
RUN yarn install \
    && yarn compile

# Re-use the dev container to create a production-ready node_modules dir
FROM dev AS build
WORKDIR /service

RUN rm -rf /service/node_modules\
    && yarn install --production=true \
    && yarn cache clean

FROM mybaseimage AS prod
WORKDIR /service

COPY --from=build /service/dist/ .
COPY --from=build /service/node_modules/ .

# https://github.com/nodejs/docker-node/blob/main/docs/BestPractices.md#handling-kernel-signals
RUN apk add --no-cache dumb-init


EXPOSE 5678
ENTRYPOINT ["/usr/bin/dumb-init", "--"]
CMD ["node", "dist/server/server.js"]

My package.json

"serve": "node dist/server/server.js",
"start": "concurrently \"docker-compose up\" \"yarn watch\"",

My earlier working Dockerfile was

FROM mybaseimage

#set working directory
WORKDIR /service

# Copy the needed files into the container
COPY src ./src
COPY package*.json ./
COPY yarn.lock ./
COPY tsconfig.json ./

RUN apk update
RUN apk add python3
RUN echo python3 --version
RUN yarn install
RUN yarn compile


EXPOSE 5678
ENTRYPOINT ["npm", "run", "serve"]

CodePudding user response：

In the final stage, you are COPYing the dist and node_modules trees from the build stage into the current directory. You need to explicitly state the subdirectory names on the right-hand side of COPY.

COPY --from=build /service/dist/ ./dist/
COPY --from=build /service/node_modules/ ./node_modules/

Also see the Dockerfile reference on COPY: since the COPY source is a directory, the contents of the directory are copied to the destination and not the directory itself. This differs from the normal Unix cp or mv commands.

You should be able to verify this running a debugging container on top of your built image; for example

docker run --rm your-image ls

should show the server subdirectory from the build dist tree, as well as all of the individual installed Node packages, all directly in the image's /service directory and not in subdirectories.