#!/bin/bash

#Author: Guido Diepen

#Convenience script that can help me to easily create a clone of a given
#data volume. The script is mainly useful if you are using named volumes

# On both hosts you should have running docker diemon
# and have access to root obviously.

# arg: $1: source volume name
# arg: $2: target host
# arg: $3: target volume name

#First check if the user provided all needed arguments
if [ "$1" = "" ]
then
        echo "Please provide a source volume name"
        exit
fi

if [ "$2" = "" ]
then
        echo "Please provide a target host (e.g. 1.1.1.1)"
        exit
fi

if [ "$3" = "" ]
then
        echo "Please provide a target volume name"
        exit
fi


#Check if the source volume name does exist
docker volume inspect $1 > /dev/null 2>&1
if [ "$?" != "0" ]
then
        echo "The source volume \"$1\" does not exist"
        exit
fi

# todo? or not needed, cauz it will just be replaced?
#Now check if the destinatin volume name does not yet exist
# docker volume inspect $2 > /dev/null 2>&1
#
# if [ "$?" = "0" ]
# then
#         echo "The destination volume \"$2\" already exists"
#         exit
# fi

docker run --rm \
           -v $1:/from alpine ash -c \
           "cd /from ; tar -cf - . " | \
           ssh $2 \
           'docker run --rm -i -v $3:/to alpine ash -c "cd /to ; tar -xpvf - "'