fix retry for PoolTimeout error

lib/moped/failover.rb

@@ -21,7 +21,8 @@ module Failover
       Errors::ConnectionFailure => Retry,
       Errors::CursorNotFound => Ignore,
       Errors::OperationFailure => Reconfigure,
-      Errors::QueryFailure => Reconfigure
+      Errors::QueryFailure => Reconfigure,
+      Errors::PoolTimeout => Retry
     }.freeze
 
     # Get the appropriate failover handler given the provided exception.

lib/moped/failover/retry.rb

@@ -9,7 +9,7 @@ module Failover
     module Retry
       extend self
 
-      # Executes the failover strategy. In the case of retyr, we disconnect and
+      # Executes the failover strategy. In the case of retry, we disconnect and
       # reconnect, then try the operation one more time.
       #
       # @example Execute the retry strategy.
@@ -24,11 +24,13 @@ module Retry
       #
       # @since 2.0.0
       def execute(exception, node)
-        node.disconnect
+        node.disconnect unless exception.is_a?(Errors::PoolTimeout)
         begin
           node.connection do |conn|
             yield(conn) if block_given?
           end
+        rescue Errors::PoolTimeout => e
+          raise Errors::ConnectionFailure.new e
         rescue Exception => e
           node.down!
           raise(e)

spec/moped/session_spec.rb

@@ -347,4 +347,24 @@
       nodes.last.should be_down
     end
   end
+
+  context "when connections on pool are busy" do
+    let(:session) do
+      Moped::Session.new([ "127.0.0.1:27017" ], database: "moped_test", pool_size: 1, pool_timeout: 0.2, max_retries: 30, retry_interval: 1)
+    end
+
+    it "should retry the operation" do
+      session[:test].find({ name: "test_counter" }).update({'$set' => {'cnt' => 1}}, {upsert: true})
+
+      results = []
+
+      300.times.map do |i|
+        Thread.new do
+          results.push session[:test].find({ name: "test_counter" }).first["cnt"]
+        end
+      end.each {|t| t.join }
+
+      expect(results.count).to eql(300)
+    end
+  end
 end