Example showing how to get a NodeJS app into a Docker container w/ cached layers.

Dockerfile

# Set the baseImage.
# The ECR node:14 image is noticeably faster than dockerhub.
FROM public.ecr.aws/bitnami/node:14

# Set the working dir to /example-directory.
WORKDIR /example-directory

# Rather than copying the entire working directory only copy the package.json file. 
# This takes advantage of cached Docker layers and doesn't rebuild the modules each time the container is rebuilt. 
# If the package.json file changes then the modules will be rebuilt.
COPY package.json yarn.lock ./

# Install dependencies
RUN yarn install

# Bundle app source
COPY . .

# Create example user.
# --system Create a system account
# --group Create a system group
RUN adduser --system --group example

# Change owner from root -> example.
RUN chown -R example /example-directory

# Set the username.
USER example

# Define the network port that this container will listen on at runtime.
EXPOSE 507

# Start the app.
CMD [ "yarn", "build" ]