# docker-companion [![Build Status](https://travis-ci.org/mudler/docker-companion.svg?branch=master)](https://travis-ci.org/mudler/docker-companion)

docker-companion is a candy mix of tools for docker written in Golang and directly using Docker API calls. As for now it allows to squash and unpack an image.

## Reinventing the wheel?

Problem arises with current tools to squash/unpack images since mostly of them are scripted. I personally needed a static implementation with no-deps hell that i could use in my CI pipeline easily (and also to get the job done).

## Download and unpack image 

Note: Doesn't require a docker daemon running on the host.

    docker-companion download my-awesome-image /unpacked_rootfs
    
Downloads and reconstruct all the image layers,
unpacking the content to the directory given as second argument.

## Squash an image

The resulting image will loose metadata, but it is handy to reduce image size:

    docker-companion squash my-awesome-image my-awesome-image-squashed

You can also make it pull before squashing it:

    docker-companion --pull squash my-awesome-image my-awesome-image-squashed:mytag

Or just squashing an image

    docker-companion squash my-awesome-image

to directly remove the intermediary (the source image, which will loose the tag)

    docker-companion squash --remove my-awesome-image

## Unpack an image

    docker-companion unpack my-awesome-image /my/path

The path must be absolute, and you must run it with root permission to keep file permissions.

You can squash the image right before unpacking it too:

    docker-companion --pull unpack --squash my-awesome-image /my/path

It can be handy sometimes to squash the image before unpacking it (very few cases where the latter fails)

You can supply also the --fatal global option to treat all warnings as fatal:

    docker-companion --fatal --pull unpack --squash my-awesome-image /my/path

## Get Latest release from github for amd64

```bash
curl -s https://api.github.com/repos/mudler/docker-companion/releases/latest \
| grep "browser_download_url.*amd64" \
| cut -d : -f 2,3 \
| tr -d \" \
| wget -i - -O docker-companion
```