Sample EventStore Consumption

sample_eventstore.rb

require 'http_eventstore'
client = HttpEventstore::Connection.new

stream_name = 'accounts-002'
#event_data = { event_type: "AccountCreated",
#               data: { phoneNumber: '15128798439' }}
#client.append_to_stream(stream_name, event_data)

EventData = Struct.new(:data, :event_type)

event_data = EventData.new({amount: 1000 }, "DepositCreated")
client.append_to_stream(stream_name, event_data)

@last_event = 0
@balances = {}

def calculate_balances
  client = HttpEventstore::Connection.new
  all_accounts_stream_name = '$ce-accounts'
  events = client.read_events_forward(all_accounts_stream_name, @last_event+1, 1000).reverse

  events.each do |event|
    p event
    if event.type == "AccountCreated"
      @balances[event.stream_name] = {amount: 0, position: event.id}
    elsif event.type == "DepositCreated"
      prev_balance = @balances[event.stream_name][:amount]
      @balances[event.stream_name] = {amount: prev_balance + event.data['amount'], position: event.id}
    elsif event.type == "WithdrawalCreated"
      prev_balance = @balances[event.stream_name][:amount]
      @balances[event.stream_name] = {amount: prev_balance - event.data['amount'], position: event.id}
    end
    @last_event = event.position
  end

  @balances
end

calculate_balances
# ?> @balances
# => {"accounts-001"=>{:amount=>1000, :position=>5}}

def random_withdrawal
  @client = HttpEventstore::Connection.new
  p stream_name = "accounts-00#{rand(2)+1}"
  withdrawal_amount = rand(1000)

  if @balances[stream_name][:amount] > withdrawal_amount
    event_data = EventData.new({amount: withdrawal_amount }, "WithdrawalCreated")
    @client.append_to_stream(stream_name, event_data, @balances[stream_name][:position])
  else 
    p "NSF - depositing"
    event_data = EventData.new({amount: 1000 }, "DepositCreated")
    @client.append_to_stream(stream_name, event_data)
  end
  calculate_balances
end

n = 100
Benchmark.bm do |x|
  x.report { n.times {random_withdrawal} }
end
# 0.270000   0.070000   0.340000 (  0.665584)