OCI Registry

A Ruby library for interacting with OCI/Docker registries using the native HTTP/tar/sha format to navigate repositories and retrieve tags, metadata and other useful information.

Installation

Add this line to your application's Gemfile:

gem 'oci_registry'

And then execute:

$ bundle

Usage

Client

# Create a client for Docker Hub
client = OCIRegistry::Client.new(username: 'user', password: 'pass')

# Create a client for Google Container Registry
client = OCIRegistry::Client.new(token: 'access-token', host: 'gcr.io')

# Get image metadata
metadata = client.metadata('library/nginx', 'latest')

# List tags
client.tags('library/nginx') do |tag|
  puts tag
end

# Get manifest
manifest = client.manifest('library/nginx', 'latest')

# Download and extract layers
layers = manifest['layers']
client.download_and_extract_layers('library/nginx', layers, 'config.json')

URI Parser

# Parse Docker/OCI URIs
uri = OCIRegistry::URI.new('docker://docker.io/library/nginx:latest')
puts uri.repository # => "library/nginx"
puts uri.tag        # => "latest"
puts uri.host       # => "docker.io"

Utils

# Write skopeo policy file
OCIRegistry::Utils.write_policy(filename: "policy.json")

# Calculate SHA256 of a file
sha = OCIRegistry::Utils.calculate_sha256("/path/to/file")

# Sum layers from skopeo inspect output
size = OCIRegistry::Utils.sum_layers(skopeo_inspect_json)

# Copy image between registries
digest = OCIRegistry::Utils.copy_image(
  src_user: "user1", src_pass: "pass1",
  dst_user: "user2", dst_pass: "pass2",
  src_oci: "docker.io/library/nginx",
  src_commit: "latest",
  dst_oci: "my-registry.com/nginx",
  dst_commit: "latest"
)

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests.

Contributing

Bug reports and pull requests are welcome.

License

The gem is available as open source under the terms of the MIT License.