Class: Sourced::Backends::ActiveRecordBackend

Inherits:
Object
  • Object
show all
Defined in:
lib/sourced/backends/active_record_backend.rb

Defined Under Namespace

Classes: CommandRecord, EventRecord, StreamRecord

Constant Summary collapse

PREFIX = 
'sourced'

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ ActiveRecordBackend

Returns a new instance of ActiveRecordBackend.



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# File 'lib/sourced/backends/active_record_backend.rb', line 50

def initialize
  @serialize_event = method(:serialize_jsonb_event)
  @deserialize_event = method(:deserialize_jsonb_event)
  if EventRecord.connection.class.name == 'ActiveRecord::ConnectionAdapters::SQLite3Adapter'
    @serialize_event = method(:serialize_sqlite_event)
    @deserialize_event = method(:deserialize_sqlite_event)
  end
end

Class Method Details

.installed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/sourced/backends/active_record_backend.rb', line 36

def self.installed?
  ActiveRecord::Base.connection.table_exists?(EventRecord.table_name) &&
    ActiveRecord::Base.connection.table_exists?(StreamRecord.table_name) &&
    ActiveRecord::Base.connection.table_exists?(CommandRecord.table_name)
end

.table_prefix ⇒ Object 



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# File 'lib/sourced/backends/active_record_backend.rb', line 32

def self.table_prefix
  @table_prefix || PREFIX
end

.table_prefix=(prefix) ⇒ Object 



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# File 'lib/sourced/backends/active_record_backend.rb', line 25

def self.table_prefix=(prefix)
  @table_prefix = prefix
  EventRecord.table_name = [prefix, '_events'].join
  StreamRecord.table_name = [prefix, '_streams'].join
  CommandRecord.table_name = [prefix, '_commands'].join
end

.uninstall! ⇒ Object 



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# File 'lib/sourced/backends/active_record_backend.rb', line 42

def self.uninstall!
  raise 'Not in test environment' unless ENV['ENVIRONMENT'] == 'test'

  ActiveRecord::Base.connection.drop_table(EventRecord.table_name)
  ActiveRecord::Base.connection.drop_table(CommandRecord.table_name)
  ActiveRecord::Base.connection.drop_table(StreamRecord.table_name)
end

Instance Method Details

#append_events(events) ⇒ Object 



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# File 'lib/sourced/backends/active_record_backend.rb', line 130

def append_events(events)
  rows = events.map { |e| serialize_event(e) }
  EventRecord.insert_all!(rows)
  true
rescue ActiveRecord::RecordNotUnique => e
  raise Sourced::ConcurrentAppendError, e.message
end

#clear! ⇒ Object 



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# File 'lib/sourced/backends/active_record_backend.rb', line 61

def clear!
  raise 'Not in test environment' unless ENV['ENVIRONMENT'] == 'test'

  EventRecord.delete_all
  CommandRecord.delete_all
  StreamRecord.delete_all
end

#installed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/sourced/backends/active_record_backend.rb', line 59

def installed? = self.class.installed?

#read_event_batch(causation_id) ⇒ Object 



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# File 'lib/sourced/backends/active_record_backend.rb', line 138

def read_event_batch(causation_id)
  EventRecord.where(causation_id:).order(:global_seq).map do |record|
    deserialize_event(record)
  end
end

#read_event_stream(stream_id, after: nil, upto: nil) ⇒ Object 



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# File 'lib/sourced/backends/active_record_backend.rb', line 144

def read_event_stream(stream_id, after: nil, upto: nil)
  query = EventRecord.where(stream_id:)
  query = query.where('seq > ?', after) if after
  query = query.where('seq <= ?', upto) if upto
  query.order(:global_seq).map do |record|
    deserialize_event(record)
  end
end

#reserve_next ⇒ Object

 TODO: locking the stream could be done in a single SQL query, or using an SQL function.



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# File 'lib/sourced/backends/active_record_backend.rb', line 93

def reserve_next(&)
  command_record = transaction do
    cmd = CommandRecord
      .joins("INNER JOIN #{StreamRecord.table_name} ON #{CommandRecord.table_name}.stream_id = #{StreamRecord.table_name}.stream_id")
      .where(["#{StreamRecord.table_name}.locked = ?", false])
      .order("#{CommandRecord.table_name}.id ASC")
      .lock # "FOR UPDATE"
      .first

    if cmd
      StreamRecord.where(stream_id: cmd.stream_id).update(locked: true)
    end
    cmd
  end

  cmd = nil
  if command_record
    # TODO: find out why #data isn't already
    # deserialized here
    data = JSON.parse(command_record.data, symbolize_names: true)
    cmd = Message.from(data)
    yield cmd
    # Only delete the command if processing didn't raise
    command_record.destroy
  end
  cmd
ensure
  # Always unlock the stream
  if command_record
    StreamRecord.where(stream_id: command_record.stream_id).update(locked: false)
  end
end

#schedule_command(stream_id, command) ⇒ Object 



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# File 'lib/sourced/backends/active_record_backend.rb', line 84

def schedule_command(stream_id, command)
  CommandRecord.transaction do
    StreamRecord.upsert({ stream_id: }, unique_by: :stream_id)
    CommandRecord.create!(stream_id:, data: command.to_json)
  end
end

#schedule_commands(commands) ⇒ Object

 TODO: if all commands belong to the same stream_id we could upsert the streams table once here



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# File 'lib/sourced/backends/active_record_backend.rb', line 71

def schedule_commands(commands)
  return false if commands.empty?

  # TODO: here we could use multi_insert
  # for both streams and commands
  CommandRecord.transaction do
    commands.each do |command|
      schedule_command(command.stream_id, command)
    end
  end
  true
end

#transaction ⇒ Object 



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# File 'lib/sourced/backends/active_record_backend.rb', line 126

def transaction(&)
  EventRecord.transaction(&)
end