Building Docker Images - Check the Size

Getting the size of docker images after building it ...

Stefan Walther

When building Docker Images one can easily forget to optimize the size of the images. Therefore I prefer to always get the immediate feedback, how large the resulting docker images is.

Here’s a small, reusable script, I use in some of my projects, a reusable section in a Makefile.

DOCKER_IMAGE_NAME = <your-docker-image-name>
DOCKER_IMAGE_SIZE = $(shell docker images --format "{{.Repository}} {{.Size}}" | grep $(DOCKER_IMAGE_NAME) | cut -d\   -f2)

build:          ## Build the docker image
  docker build -t $(DOCKER_IMAGE_NAME) .
  @echo ''
  @echo "Size of the image: ${DOCKER_IMAGE_SIZE}"
.PHONY: build


Running make build now gives me:

Showing the image size after building the Docker image

OK, very good, I immediately got the feedback that this image is really big, so I do not forget to focus immediately on some improvements.


A nice and tiny helper to be added to the toolbox.

comments powered by Disqus