AvroPinions

Opinionated stuff around AVRO in Ruby. Goals:

• Support some generic schema registry. You plug it in, conform to my API spec.
• Support Single-Object Encoding out of the box
  • Writing for now. Maybe reading later.

Installation

Add this line to your application's Gemfile:

gem 'avro_pinions'

And then execute:

$ bundle

Or install it yourself as:

$ gem install avro_pinions

Usage

Here's a full example:

# define a publisher. It has to have one method: `#publish`
class MyPublisher
  # publish needs receive a topic and a message
  # message is binary encoded AVRO data
  def publish(topic, message)
    # depending on how your transport mechanism works you may need to convert
    # binary data to ascii characters or something. I recommend Base64 if you
    # have to do that
    extra_encoded = make_binary_data_wire_safe(message)
    SomeTransferMechanismIOwn.send(topic, extra_encoded)
  end
end

# configure AvroPinions
AvroPinions.configure({
  wire_format: :single_object,
  schema_registry: {
    type: :file,
    schema_path: 'doc/schemas'
  },
  publisher: MyPublisher.new
})

# define a message. They inherit from AvroPinions::Message
class SomeMessage < AvroPinions::Message
  # define these constants or override `topic`, `schema`, and `namespace`
  # methods
  TOPIC = "some_topic"
  SCHEMA = "SchemaName"
  NAMESPACE = "com.company.namespace"

  def initialize(data)
    @data = data
  end

  # this method must return a json object that will be encoded with the AVRO
  # schema
  def record
    { key: @data.value }
  end
end

message = SomeMessage.new({ data... })
if message.valid?
  AvroPinions.publish(message)
end

Or you can provide things more manually if you want:

AvroPinions.configure({ wire_format: :single_object })

class Message < AvroPinions::Message
  def initialize(avro_schema, data)
    @avro_schema = avro_schema
    @data = data
  end

  def record
    @data
  end

  def avro_schema
    @avro_schema
  end
end

avro_schema = Avro::Schema.real_parse(json_schema_object)
Message.new(avro_schema, some_data).encode

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/jszmajda/avro_pinions. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

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