A concise way to find the compressed size of a container without needing to pull it.

docker_image_size.sh

#!/bin/bash

# Macro for finding the size of a container from any container registry,EG: mcr, gcp, or docker

# Example use: 
# dockersize docker pull mcr.microsoft.com/devcontainers/universal:3  
# linux/amd64     140.70M
# linux/arm/v6    131.74M
# linux/arm/v7    129.97M
# linux/arm64/v8  132.15M

# Credit to ddelange from this thread: https://stackoverflow.com/a/73108928/4577237

dockersize() { docker manifest inspect -v "$1" | jq -c 'if type == "array" then .[] else . end | select(.Descriptor.platform.architecture != "unknown")' |  jq -r '[ ( .Descriptor.platform | [ .os, .architecture, .variant, ."os.version" ] | del(..|nulls) | join("/") ), ( [ ( .OCIManifest // .SchemaV2Manifest ).layers[].size ] | add ) ] | join(" ")' | numfmt --to iec --format '%.2f' --field 2 | sort | column -t ; }