lib/rex/book/trade_tracker.rb

@@ -1,28 +1,28 @@
 module Rex
   module Book
-    # Trade Tracker implemented as a simple ring buffer
     class TradeTracker
-      include Enumerable
       DEFAULT_TRADE_HISTORY_LIMIT = 200
 
       attr_reader :trades
 
       def initialize(limit: DEFAULT_TRADE_HISTORY_LIMIT)
         @limit = limit
-        @trades = Array.new(limit)
+        @trades = []
-        @current_id = -1
       end
 
       def add(trade)
-        @current_id += 1
+        @trades.push(trade)
-        idx = (@current_id % @limit)
+        cap
-        @trades[idx] = trade
       end
 
-      def each(&block)
+      def fetch_trades(limit)
-        (([@current_id - @limit, 0].max)..@current_id ).each do |id|
+        @trades.last(limit)
-          yield @trades[id % @limit]
+      end
-        end
+
+      private
+
+      def cap
+        @trades = @trades.last(@limit)
       end
     end
   end

lib/rex/server/matching_engine.rb

@@ -50,7 +50,7 @@ module Rex
       end
 
       def fetch_trades(user_id)
-        @trade_tracker.each do |trade|
+        @trade_tracker.fetch_trades(50).each do |trade|
           @outbox.push(
             Messages::TradeFetchEvent.new(
               trade.id,

rex.gemspec

@@ -28,10 +28,10 @@ Gem::Specification.new do |spec|
 
   spec.add_dependency "rbtree", "~> 0.4.6"
 
-  spec.add_dependency "eventmachine", "~> 1.2"
+  spec.add_runtime_dependency "eventmachine", "~> 1.2"
-  spec.add_dependency "em-websocket", "~> 0.5"
+  spec.add_runtime_dependency "em-websocket", "~> 0.5"
 
-  spec.add_dependency "json-schema", "~> 4"
+  spec.add_runtime_dependency "json-schema", "~> 4"
   # For more information and examples about making a new gem, check out our
   # guide at: https://bundler.io/guides/creating_gem.html
 end

spec/book/trade_tracker_spec.rb

@@ -15,10 +15,10 @@ RSpec.describe Rex::Book::TradeTracker do
     end
   end
 
-  describe "#each" do
+  describe "#fetch_trades" do
     let(:n) { 3 }
     it "returns only the last n trades" do
-      expect(instance.to_a).to eq([10, 11])
+      expect(instance.fetch_trades(1)).to eq([11])
     end
   end
 end