Cache mount for faster builds in Docker - Mini Project: Build & Apply

Cache mount for faster builds

📖 Scenario: You are working on a Docker project where you want to speed up the build process by using cache mounts. This helps reuse downloaded packages and dependencies instead of fetching them every time.

🎯 Goal: Build a Dockerfile that uses --mount=type=cache to cache package manager files and speed up the build.

📋 What You'll Learn

Create a Dockerfile with a base image python:3.12-slim

Add a cache mount for the /root/.cache/pip directory during package installation

Install the requests package using pip with the cache mount

Print a message to confirm the build step

💡 Why This Matters

🌍 Real World

Caching speeds up Docker builds by reusing downloaded files, saving time and bandwidth.

💼 Career

DevOps engineers use cache mounts to optimize CI/CD pipelines and reduce build times.

1

Create the base Dockerfile

Create a Dockerfile starting with the base image python:3.12-slim using the FROM instruction.

Docker

# Your code here

Need a hint?

Use the FROM keyword followed by the exact image name python:3.12-slim.

2

Add a cache mount for pip cache

Add a RUN instruction that uses --mount=type=cache,target=/root/.cache/pip to cache pip files during package installation.

Docker

FROM python:3.12-slim
# Your code here

Need a hint?

Use RUN --mount=type=cache,target=/root/.cache/pip pip install requests exactly.

3

Add a confirmation message

Modify the RUN instruction to print "Installed requests with cache" after installing the package.

Docker

FROM python:3.12-slim
RUN --mount=type=cache,target=/root/.cache/pip pip install requests
# Your code here

Need a hint?

Use sh -c to run both commands in one RUN instruction.

4

Build and verify the Docker image

Build the Docker image and run it to verify the output contains Installed requests with cache.

Docker

FROM python:3.12-slim
RUN --mount=type=cache,target=/root/.cache/pip sh -c "pip install requests && echo 'Installed requests with cache'"
# Your code here

Need a hint?

Run docker build --progress=plain . and check the output for the confirmation message.