Bash script wrapper for generating a singularity image from a local Docker image

docker2singularity.sh

#!/bin/bash

# Based on https://github.com/sylabs/singularity/issues/1537
# Usage: bash docker2singularity.sh mydockerimg mysingularity.simg

set -ueo pipefail

IMG=$1
FILEOUT=$2
PORT=${3:-5000}

if [ -f $FILEOUT ]; then

        echo "File $FILEOUT exists!"
        exit 1
fi

docker run -d -p $PORT:5000 --restart=always --name "registry-$IMG" registry:2

# Push local docker container to it
docker tag $IMG localhost:$PORT/$IMG
docker push localhost:$PORT/$IMG

# Build singularity container
SINGULARITY_NOHTTPS=1 singularity build $FILEOUT docker://localhost:$PORT/$IMG

docker rm -f "registry-$IMG"
docker rmi localhost:$PORT/$IMG