skopeo

Please be aware skopeo is still work in progress

skopeo is a command line utility which is able to inspect an image from a remote Docker registry. By inspect I mean it just fetches the image's manifest and it is able to show you a docker inspect-like json output. This tool, in constrast to docker inspect, helps you gather useful information about an image before pulling it (and use disk space) - e.g. - which tags are available for the given image? which labels the image has?

Example:

# show image's labels
$ skopeo registry.access.redhat.com/rhel7 | jq '.Config.Labels'
{
  "Architecture": "x86_64",
  "Authoritative_Registry": "registry.access.redhat.com",
  "BZComponent": "rhel-server-docker",
  "Build_Host": "rcm-img04.build.eng.bos.redhat.com",
  "Name": "rhel7/rhel",
  "Release": "38",
  "Vendor": "Red Hat, Inc.",
  "Version": "7.2"
}

# show image's tags
$ skopeo docker.io/fedora | jq '.RepoTags'
[
  "20",
  "21",
  "22",
  "23",
  "heisenbug",
  "latest",
  "rawhide"
]

Building

$ git clone https://github.com/runcom/skopeo
$ make

Installing

$ sudo make install

License

MIT TODO

• add tests (integration with deployed registries in container - Docker-like)
• get rid of Docker (meaning make this work w/o needing Docker installed)
• require image argument to be fully qualified (not the Docker way)
• drop the Registry field in the response because of the point above :)

NOT TODO

• provide a format flag - just use the awesome jq