Merge pull request #142 from daipom/excluded-port-ranges

Consider excluded port ranges for Windows

lib/serverengine/socket_manager.rb

@@ -77,11 +77,10 @@ def self.generate_path
           port = ENV['SERVERENGINE_SOCKETMANAGER_PORT']
           return port.to_i if port
 
-          for port in get_dynamic_port_range
-            if `netstat -na | findstr "#{port}"`.length == 0
-              return port
-            end
-          end
+          excluded_port_ranges = get_excluded_port_ranges
+          get_dynamic_port_range
+            .reject { |port| excluded_port_ranges.any? { |range| range.cover?(port) } }
+            .find { |port| `netstat -na | findstr "#{port}"`.length == 0 }
         else
           base_dir = (ENV['SERVERENGINE_SOCKETMANAGER_SOCK_DIR'] || '/tmp')
           File.join(base_dir, 'SERVERENGINE_SOCKETMANAGER_' + Time.now.utc.iso8601 + '_' + Process.pid.to_s)
@@ -203,6 +202,27 @@ def self.get_dynamic_port_range
             return 49152..65535
           end
         end
+
+        def self.get_excluded_port_ranges
+          # Example output of netsh:
+          #
+          # Protocol tcp Port Exclusion Ranges
+          #
+          # Start Port    End Port
+          # ----------    --------
+          #       2869        2869
+          #      49152       49251
+          #      50000       50059     *
+          #      57095       57194
+          #
+          # * - Administered port exclusions.
+          #
+          `netsh int ipv4 show excludedportrange tcp`
+            .force_encoding("ASCII-8BIT")
+            .lines
+            .map { |line| line.match(/\s*(\d+)\s*(\d+)[\s\*]*/) ? $1.to_i..$2.to_i : nil }
+            .compact
+        end
       end
     end
 

spec/socket_manager_spec.rb

@@ -1,4 +1,5 @@
 require 'socket'
+require 'rr'
 
 describe ServerEngine::SocketManager do
   include_context 'test server and worker'
@@ -21,9 +22,23 @@
 
   if ServerEngine.windows?
     context 'Server.generate_path' do
-      it 'returns socket path as port number' do
-        path = SocketManager::Server.generate_path
-        expect(path).to be_between(49152, 65535)
+      context 'with socket path as port number' do
+        it 'returns a port in the dynamic port range' do
+          path = SocketManager::Server.generate_path
+          expect(path).to be_between(49152, 65535)
+        end
+
+        it 'returns a port which is not excluded' do
+          excluded_port_ranges = [
+            49152..49251,
+            50000..50059,
+          ]
+          RR.stub(SocketManager::Server).get_excluded_port_ranges { excluded_port_ranges }
+          path = SocketManager::Server.generate_path
+          excluded_port_ranges.each do |range|
+            expect(path).not_to be_between(range.first, range.last)
+          end
+        end
       end
 
       it 'can be changed via environment variable' do