ipcr / web

Web frontend for InterPlanetary Container Registry

InterPlanetary Container Registry

Disclaimer: this project is in the early prototype stage.

The ultimate goal of this project is to build a fully decentralised version of Docker Hub with the following features:

• Images and their metadata are stored on p2p storage.
• Private images are encrypted.
• Decentralised identification.
• Web frontend is running on p2p network.

You can check a prototype of the web frontend in ipcr/web. It looks like an extremely simplified version of Docker Hub. Live demo is running on Fleek.

The project was started at HackFS. HackFS is a virtual Hackathon by ETHGlobal and Protocol Labs.

The following sections of the document describe how to build a rudimentary public container registry using IPFS, IPNS and DNSLink.

In the future a tool called ipcr will be built. So that you can simply ipcr push image:tag to publish an image. And ipcr pull some.domain/image:tag to pull an image.

Prerequisites

All commands below were tested on macOS version 10.15.5 running Docker Desktop 2.3.0.3.

Install IPFS

You can follow the official guide. But, using Homebrew is quicker:

$ brew install ipfs

Initialize IPFS repository

To initialize the repository, run the following command:

$ ipfs init

For more details, see IPFS documentation.

Take IPFS node online

To join your node to the public network, run the ipfs daemon:

$ ipfs daemon

Initialize container registry

To create an empty container registry and enable IPNS for it, run the following commands:

$ mkdir .ipcr
$ ipfs add -Qr .ipcr
QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn
$ ipfs name publish QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn
Published to QmTw9u8R3FCh2DR1t6PvkWibVnZXJfujzEKV2o4SRrTPLV: /ipfs/QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn

Note, that publishing to IPNS takes some time.

The last hash, next to the folder CID, is the one to remember, call it $PEER_ID for now:

$ PEER_ID=QmTw9u8R3FCh2DR1t6PvkWibVnZXJfujzEKV2o4SRrTPLV

Edit your DNS records

Assume you have the domain name your.domain and can access your registrar's control panel to manage DNS entries for it.

Create a DNS TXT record (DNSLink), with the key your.domain. and the value dnslink=/ipns/$PEER_ID where $PEER_ID is the value from the section above.

Once you've created that record, and it has propagated you should be able to find it.

$ dig +noall +answer TXT your.domain
your.domain.            60      IN      TXT     "dnslink=/ipns/$PEER_ID"

You can now list registry contents using your.domain:

$ ipfs ls /ipns/your.domain

Note, that the registry is still empty. Time to add some images!

Push Docker image to IPFS

First, you should pull some image from Docker Hub:

$ docker pull -q ipfs/go-ipfs:v0.6.0

Next, save this image to your registry directory:

$ mkdir -p .ipcr/go-ipfs/tags/v0.6.0
$ echo 'Go implementation of IPFS, the InterPlanetary FileSystem' > .ipcr/go-ipfs/README-short.txt
$ docker save ipfs/go-ipfs:v0.6.0 | tar -xf - -C .ipcr/go-ipfs/tags/v0.6.0

Finally, publish the updated version of your container registry to IPFS:

$ ipfs add -Qr .ipcr
QmcZqjtj3QhYEAr8a9Uu1A3vThtn5uee9iMjVJEzMYaY4p
$ ipfs name publish /ipfs/QmcZqjtj3QhYEAr8a9Uu1A3vThtn5uee9iMjVJEzMYaY4p
Published to QmTw9u8R3FCh2DR1t6PvkWibVnZXJfujzEKV2o4SRrTPLV: /ipfs/QmcZqjtj3QhYEAr8a9Uu1A3vThtn5uee9iMjVJEzMYaY4p

Pull Docker image from IPFS

To pull an image you download it from IPFS and then load using Docker:

$ ipfs get -o go-ipfs:v0.6.0 /ipns/your.domain/go-ipfs/tags/v0.6.0
$ tar --strip-components 1 -cf - go-ipfs:v0.6.0 | docker load

Note, that downloading the image as a TAR archive from IPFS using --archive and loading this archive using Docker doesn't work. Because the leading path element of the archive will be v0.6.0 in that case. This is not expected by Docker and you'll get a non obvious error saying open /var/lib/docker/tmp/docker-import-787571586/v0.6.0/json: no such file or directory when loading the image. Therefore, the image directory is archived with --strip-components 1 before loading.

Prior art

The following list contains a few projects that implement a Docker Registry on top of IPFS:

• Storage Driver: Add an IPFS driver
• IPDR: InterPlanetary Docker Registry
• Docker Registry for IPFS

License

This project is licensed under the MIT License–see the LICENSE file for details.