Multi-stage for different environments in Docker - Mini Project: Build & Apply

Multi-stage Dockerfile for Different Environments

📖 Scenario: You are working on a simple web application that needs to be built and deployed in two different environments: development and production. Each environment requires a different setup inside the Docker image.In development, you want to include debugging tools and keep the source code inside the image. In production, you want a smaller image with only the built application and no extra tools.

🎯 Goal: Create a multi-stage Dockerfile that builds the application in a builder stage, then creates two separate final images: one for development with debugging tools and source code, and one for production with only the built app.

📋 What You'll Learn

Create a builder stage that copies source code and builds the app

Create a development stage that copies from builder and adds debugging tools

Create a production stage that copies only the built app from builder

Use multi-stage syntax with FROM and AS keywords

Print the final Dockerfile content

💡 Why This Matters

🌍 Real World

Multi-stage Dockerfiles are used in real projects to create optimized images for different environments, saving space and improving security.

💼 Career

Understanding multi-stage builds is important for DevOps roles to manage container images efficiently and support continuous integration and deployment pipelines.

1

Create the builder stage

Write the first stage of the Dockerfile named builder that uses the python:3.12-slim image. Copy the source code folder src/ into /app inside the container and set the working directory to /app. Then run the command pip install -r requirements.txt to install dependencies.

Docker

# Write the builder stage of the Dockerfile
# Your code here

Need a hint?

Use FROM python:3.12-slim AS builder to start the builder stage.

Remember to copy the src/ folder and set the working directory.

2

Add the development stage

Add a new stage named development that starts from python:3.12-slim. Copy everything from the builder stage's /app directory into /app in this stage. Then install the debugging tool ipdb by running pip install ipdb. Set the working directory to /app.

Docker

FROM python:3.12-slim AS builder
WORKDIR /app
COPY src/ /app
RUN pip install -r requirements.txt

# Add the development stage below
# Your code here

Need a hint?

Use COPY --from=builder /app /app to copy files from the builder stage.

Install ipdb with pip install ipdb.

3

Add the production stage

Add a new stage named production that starts from python:3.12-slim. Copy only the built application files from the builder stage's /app directory into /app. Set the working directory to /app. Do not install debugging tools here.

Docker

FROM python:3.12-slim AS builder
WORKDIR /app
COPY src/ /app
RUN pip install -r requirements.txt

FROM python:3.12-slim AS development
WORKDIR /app
COPY --from=builder /app /app
RUN pip install ipdb

# Add the production stage below
# Your code here

Need a hint?

Start the production stage with FROM python:3.12-slim AS production.

Copy files from the builder stage but do not install extra packages.

4

Print the complete Dockerfile

Print the entire Dockerfile content as a single string exactly as written in the previous steps.

Docker

FROM python:3.12-slim AS builder
WORKDIR /app
COPY src/ /app
RUN pip install -r requirements.txt

FROM python:3.12-slim AS development
WORKDIR /app
COPY --from=builder /app /app
RUN pip install ipdb

FROM python:3.12-slim AS production
WORKDIR /app
COPY --from=builder /app /app

# Print the Dockerfile content below
# Your code here

Need a hint?

Use a print statement to output the entire Dockerfile content as a string.