Reduce your Docker build time from 3 min to 4 second

This is a sample repository for a HelloWorld springboot project, showcasing various ways through which image building can be reduced drastically.

The complete process is divided in 4 steps

• Initial problematic build
• Solution1
• Solution2
• Solution3

Initial problematic build

In this section we are simulating the time consuming image building process where image build process takes >3 minutes Problematic Docker file You can run make target to validate the image creation part

$ make problem-build-package-with-time
real	3m3.356s
user	0m1.221s
sys	0m1.067s

Solution1

The base of the problem is that every time image is built dependencies are downloaded, if somehow we can fix that problem the problem would be solved. Docker build has an issue where you can't do a volume mounting as a result of which you can't leverage reuse of already downloaded files. In this solution we have broken artefact generation and image creation. Artefact generation is done using a docker container so that we can resuse local maven repository
Solution1 Docker file You can run make target to validate the image creation part

$ make solution1-build-package-with-time
time make solution1-build-package >/dev/null 2>&1

real	0m15.212s
user	0m0.288s
sys	0m0.286s

Solution2

Leverage layering capability of Docker, created separate layer for dependencies download Solution1 Docker file You can run make target to validate the image creation part

$ make solution2-build-package-with-time
time make solution2-build-package >/dev/null 2>&1

real	1m32.215s
user	0m0.788s
sys	0m0.787s

Solution3

Used interesting concept of intermediate builder image so that only delta dependencies will be downloaded Solution3 builder Docker file Solution3 Docker file You can run make target to validate the image creation part

$ make solution3-build-package-with-time
time make solution3-build-package >/dev/null 2>&1

real	0m4.800s
user	0m0.224s
sys	0m0.200s