docker-image-size-limit

Limit your docker image size with a simple CLI command. Perfect to be used inside your CI process.

Read the announcing post.

Installation

pip install docker-image-size-limit

Or use our Github Action or pre-built docker image.

Usage

We support just a single command:

$ disl your-image-name:label 300MiB
your-image-name:label exceeds 300MiB limit by 114.4 MiB

Add --max-layers flag to also lint the maximum amount of layers possible in your image:

# If your image has 7 layers:
$ disl your-image-name:label 300MiB --max-layers=5
your-image-name:label exceeds 5 maximum layers by 2

# If your image has 5 layers:
$ disl your-image-name:label 300MiB --max-layers=5
# ok!

Add --current-size flag to show the current size your image:

$ disl your-image-name:label 300MiB --current-size
your-image-name:label size is 414.4 MiB
your-image-name:label exceeds 300MiB limit by 114.4 MiB

Add --exit-zero flag to force the exit code to be 0 even if there are errors:

$ disl your-image-name:label 300MiB --exit-zero
your-image-name:label exceeds 300MiB limit by 114.4 MiB

$ echo $?
0

You can combine all flags together:

$ disl your-image-name:label 300MiB --max-layers=5 --current-size --exit-zero
your-image-name:label size is 414.4 MiB
your-image-name:label exceeds 300MiB limit by 114.4 MiB
your-image-name:label exceeds 5 maximum layers by 2

Run disl as a module:

$ python -m docker_image_size_limit your-image-name:label 300MiB
your-image-name:label exceeds 300MiB limit by 114.4 MiB

Options

You can specify your image as:

• Image name: python
• Image name with tag: python:3.6.6-alpine

You can specify your size as:

• Raw number of bytes: 1024
• Human-readable megabytes: 30 MB or 30 MiB
• Human-readable gigabytes: 1 GB or 1 GiB
• Any other size supported by humanfriendly

Programmatic usage

You can also import and use this library as python code:

from docker import from_env
from docker_image_size_limit import check_image_size

oversize = check_image_size(from_env(), 'image-name:latest', '1 GiB')
assert oversize < 0, 'Too big image!'  # negative oversize - is a good thing!

We also ship PEP-561 compatible type annotations with this library.

GitHub Action

You can also use this check as a GitHub Action:

- uses: wemake-services/docker-image-size-limit@master
  with:
    image: "$YOUR_IMAGE_NAME"
    size: "$YOUR_SIZE_LIMIT"
    # optional fields:
    max_layers: 5
    show_current_size: false
    exit_zero: false

Here's an example.

Docker Image

We have a pre-built image available.

First, pull our pre-built docker image:

docker pull wemakeservices/docker-image-size-limit

Then you can use it like so:

docker run -v /var/run/docker.sock:/var/run/docker.sock --rm \
  -e INPUT_IMAGE="$YOUR_IMAGE_NAME" \
  -e INPUT_SIZE="$YOUR_SIZE_LIMIT" \
  -e INPUT_MAX_LAYERS="$YOUR_MAX_LAYERS" \
  -e INPUT_SHOW_CURRENT_SIZE="true" \
  -e INPUT_EXIT_ZERO="true" \
  wemakeservices/docker-image-size-limit

Should I use it?

You can use this script instead:

LIMIT=1024  # adjust at your will
IMAGE='your-image-name:latest'

SIZE="$(docker image inspect "$IMAGE" --format='{{.Size}}')"
test "$SIZE" -gt "$LIMIT" && echo 'Limit exceeded'; exit 1 || echo 'Ok!'

But I prefer to reuse tools over custom bash scripts here and there.

License

MIT.