Commit (image) a Docker data container.

commit-docker-data-container.sh

#!/bin/bash

# this script does not work on OS X
[[ "$(uname -s)" == Darwin ]] && echo "This script cannot run under OS X" && exit 1

container_name=treasury_dbdata_1
container_id="$(docker inspect treasury_dbdata_1 | jq -r '.[0].Id')"
volume_path=/var/lib/mysql
tag=data

set -e

# 1st, make sure all containers that depend on the data container are stopped

docker inspect $(docker ps -q) | jq -r "$(cat <<JQ
. | map ( select (
    1 == (
        .HostConfig.VolumesFrom | arrays
        | map(
            select(
                . == "$container_id"
            )
        ) | length
    )
)) | .[].Id
JQ
)" | xargs docker stop

# 2nd, find the local path for the volume

local_volume_path="$(docker inspect "$container_id" |
    jq -r '.[0].Volumes."'"$volume_path"'"')"

# 3rd, create a fake context for image building:
context_dir=$(mktemp -d)
trap "rm -rf $context_dir" EXIT

# - hardlink volume
cp -al "$local_volume_path" $context_dir/data

# - write dockerfile
>$context_dir/Dockerfile <<DOCKERFILE
FROM mysql:latest
COPY data/ $volume_path
DOCKERFILE


# finally, the moment of truth. we actually build the image
docker build -t $tag $context_dir