Timestamp deleted from our domain event after mapping

[haines]

Our domain events don't inherit from RubyEventStore::Event, and the metadata is just a vanilla hash rather than a RubyEventStore::Metadata. That means that the DomainEvent transformation mutates our domain events here:

rails_event_store/ruby_event_store/lib/ruby_event_store/mappers/transformation/domain_event.rb

Lines 8 to 10 in 4b5652c

	metadata = domain_event.metadata.to_h
	timestamp = metadata.delete(:timestamp)
	valid_at = metadata.delete(:valid_at)

I think this code assumes that to_h returns a copy of the metadata, but with a bare hash it just returns the metadata itself.

This causes problems because the event listeners that handle the event after it's been mapped can't access the timestamp.

[mostlyobvious]

Can you show me your event implementation?

[haines]

module Plumbing
  class Event < Dry::Struct
    include Contracts::Core
    include Contracts::Builtin

    INITIAL_VERSION = 1
    Contract Or[nil, Integer] => Integer

    def self.version(version = nil)
      if version
        @version = version
      else
        @version || INITIAL_VERSION
      end
    end

    Contract KeywordArgs[event_id: String, data: Hash, metadata: Hash] => Any

    def self.new(event_id:, data:, metadata:)
      normalized_attributes = {
        data: data,
        event_id: event_id,
        metadata: metadata
      }

      new_attributes = VersionConverter.new.call(normalized_attributes, self)
      super(event_id: event_id, metadata: new_attributes[:metadata], **new_attributes[:data])
    end

    Contract None => Event

    def self.new
      super(metadata: { version: version })
    end

    Contract Any => Event

    def self.new(attributes = {})
      super(**attributes.to_h, metadata: { version: version })
    end

    Contract Class => Any

    def self.inherited(klass)
      super
      klass.attribute :event_id, (Types::UUID.default { SecureRandom.uuid })
      klass.attribute :metadata, Types::Metadata.optional
    end

    Contract None => Hash

    def to_h
      {
        event_id: event_id,
        metadata: metadata,
        data: super.except(:event_id, :metadata),
        type: type
      }
    end

    Contract None => Integer

    def version
      metadata[:version]
    end

    Contract None => Time

    def timestamp
      metadata[:timestamp]
    end

    def data
      to_h[:data]
    end

    def ==(other)
      other.instance_of?(self.class) &&
        other.event_id.eql?(event_id) &&
        other.data.eql?(data)
    end

    def matches?(attributes)
      data.slice(*attributes.keys) == attributes.slice(*data.keys)
    end

    def to_s
      "#{self.class} #{to_h}"
    end

    def type
      self.class.name
    end
    alias event_type type

    alias == eql?

    def acting_user_id
      metadata[:user_id]
    end
  end
end

[mostlyobvious]

That means that the DomainEvent transformation mutates our domain events

Right, this most probably happenned here: 1759ada#diff-ff913f01670ba8bfd82ad3c689029bf5c8589276cac50958397e108784906cb4L10

[mostlyobvious]

@haines I'm planning a smaller release this week and 3ba0549 is going to be a part of it, can you please check if it solves your issue?

[mostlyobvious]

Released: https://github.com/RailsEventStore/rails_event_store/releases/tag/v2.2.0