Builder pattern before multi-stage in Docker - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the Dockerfile line to specify the base image for the build stage.

Docker

FROM [1] AS builder

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Anode:18-alpine

Bubuntu:latest

Cpython:3.12-slim

Dalpine:3.18

Attempts:

3 left

💡 Hint

Common Mistakes

Using a base image without Node.js when building a Node app.

Choosing a heavy image like full Ubuntu unnecessarily.

The node:18-alpine image is a lightweight Node.js base image commonly used for building Node.js apps.

2fill in blank

medium

Complete the command to copy package.json and package-lock.json into the builder stage.

Docker

COPY [1] ./

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Adist/

Bpackage*.json

Cnode_modules/

Dsrc/

Attempts:

3 left

💡 Hint

Common Mistakes

Copying the entire source folder instead of just package files.

Copying node_modules folder which should be built inside the container.

Using package*.json copies both package.json and package-lock.json files needed for installing dependencies.

3fill in blank

hard

Fix the error in the RUN command to install dependencies in the builder stage.

Docker

RUN npm [1]

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Astart

Bbuild

Cinstall

Dtest

Attempts:

3 left

💡 Hint

Common Mistakes

Using npm start which runs the app instead of installing.

Using npm build which is not a valid npm command.

The npm install command installs all dependencies listed in package.json.

4fill in blank

hard

Fill both blanks to copy built files from the builder stage to the final image.

Docker

COPY --from=[1] [2] ./app/

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Abuilder

B/app/dist

C/dist

Dfinal

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong stage name in --from.

Copying from a wrong or non-existent folder.

The --from=builder copies files from the builder stage, and /dist is the typical output folder for built files.

5fill in blank

hard

Fill all three blanks to define the final image base, set working directory, and expose port.

Docker

FROM [1]
WORKDIR [2]
EXPOSE [3]

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Anode:18-alpine

B/app

C3000

Dubuntu:latest

Attempts:

3 left

💡 Hint

Common Mistakes

Using a heavy base image for final stage.

Forgetting to set working directory.

Exposing wrong or no port.

The final image uses node:18-alpine as base, sets /app as working directory, and exposes port 3000 for the app.