git pre-commit hook preventing large files

_Instructions.md

Usage

You can use in two ways.

1. Directly as the pre-commit hook in your .git/hooks folder.

2. With Husky by updating your package.json with:

"husky": {
    "hooks": {
      "pre-commit": "sh ./some-path/pre-commit-prevent-large-files.sh"
    }
}

Installation

@guysmoilov wrote an awesome installer script over here that means this hook will be added to all future repos you clone; how cool!

Credits

Based on @kiwidamien's original gist here

Alternatives

pre-commit is "a framework for managing and maintaining multi-language pre-commit hooks" and has a hook you can plug-in called: check-added-large-files. pre-commit is built with Python though, so you'll need Python installed.

pre-commit-prevent-large-files.sh

#!/bin/bash

# This is a pre-commit hook that ensures attempts to commit files that are
# larger than $limit to your _local_ repo fail, with a helpful error message.

# Maximum file size limit in bytes
limit=$(( 5 * 2**20 )) # 5MB
limitInMB=$(( $limit / 2**20 ))

# Move to the repo root so git files paths make sense
repo_root=$( git rev-parse --show-toplevel )
cd $repo_root

empty_tree=$( git hash-object -t tree /dev/null )

if git rev-parse --verify HEAD > /dev/null 2>&1
then
	against=HEAD
else
	against="$empty_tree"
fi

# Set split so that for loop below can handle spaces in file names by splitting on line breaks
IFS='
'

echo "Checking staged file sizes"
shouldFail=false
# `--diff-filter=d` -> skip deletions
for file in $( git diff-index --cached --diff-filter=d --name-only "$against" ); do
	# Skip for directories (git submodules)
	if [[ -f "$file" ]]; then
		file_size=$( ls -lan $file | awk '{ print $5 }' )
		if [ "$file_size" -gt  "$limit" ]; then
	    	echo File $file is $(( $file_size / 2**20 )) MB, which is larger than our configured limit of $limitInMB MB
        	shouldFail=true
		fi
	fi
done

if $shouldFail
then
    # echo If you really need to commit this file, you can push with the --no-verify switch, but the file should definitely, definitely be under $limitInMB MB!!!
    echo Reduce the file size and retry...
    echo Commit aborted
    exit 1;
fi