如何在 Docker 构建中缓存 node_modules？

Question

I've been trying for some time to cache node_modules on a Docker build. I've tried several approaches including the one here , but without success.

My main reason to cache is because it takes 30+ minutes to build my image, which is way too much.

My Dockerfile :

# This image will be based on the oficial nodejs docker image
FROM node:4.2.1

RUN npm install -g jspm@0.17.0-beta.7 && \
    npm install -g gulp && \
    npm install -g tsd

# Use changes to package.json to force Docker not to use the cache
# when we change our application's nodejs dependencies:
ADD package.json /src/package.json
RUN cd /src && npm install

# Put all our code inside that directory that lives in the container
ADD . /src

# Set in what directory commands will run
WORKDIR /src

# Install dependencies
RUN cd /src && \
    tsd reinstall -so && \
    jspm install && \
    gulp build -p

# Tell Docker we are going to use this port
EXPOSE 3000

# The command to run our app when the container is run
CMD ["npm", "run", "start-production"]

I do not have a .dockerignore file. I added one before but it still didn't cache my node_modules .

So, how to I cache my node_modules ? Feel free to suggest modifications to the Dockerfile .

Thanks!

Answer 1

I'm not sure whether it is the root of the error, but try to specify the destination folder in the ADD command and not the destination file .

ADD package.json /src

Moreover, you can use COPY instead of ADD ( ADD can work with url and archives but you don't need it here).

You can also specify your working directory earlier in the file.

Try with this code :

    # This image will be based on the official nodejs docker image
    FROM node:4.2.1
    
    RUN npm install -g jspm@0.17.0-beta.7 && \
        npm install -g gulp && \
        npm install -g tsd

    # Set in what directory commands will run
    WORKDIR /src
    
    # Use changes to package.json to force Docker not to use the cache
    # when we change our application’s nodejs dependencies:
    COPY package.json ./

    RUN npm install
    
    # Put all our code inside that directory that lives in the container
    COPY . ./
    
    # Install dependencies
    RUN tsd reinstall -so && \
        jspm install && \
        gulp build -p
    
    # Tell Docker we are going to use this port
    EXPOSE 3000
    
    # The command to run our app when the container is run
    CMD ["npm", "run", "start-production"]