trying picking ports at random instead of in ascending order

neo4j · Jun 29, 2017 · b2e2258 · b2e2258
1 parent 00e2a2d
commit b2e2258
Show file tree

Hide file tree

Showing 2 changed files with 13 additions and 39 deletions.
diff --git a/enterprise/causal-clustering/src/test/java/org/neo4j/causalclustering/DefaultPortProbe.java b/enterprise/causal-clustering/src/test/java/org/neo4j/causalclustering/DefaultPortProbe.java
@@ -51,36 +51,6 @@ public boolean isOccupied( int port )
             return true;
         }
 
-//        // poke at the port and as a side-effect, waste some time
-//        try ( Socket ignored = new Socket( "0.0.0.0", port ) )
-//        {
-//
-//        }
-//        catch ( IOException e )
-//        {
-//            return true;
-//        }
-//
-//        // poke at the port and as a side-effect, waste some time
-//        try ( Socket ignored = new Socket( InetAddress.getLoopbackAddress(), port ) )
-//        {
-//
-//        }
-//        catch ( IOException e )
-//        {
-//            return true;
-//        }
-        // or not because that ate all ports very quickly...
-
-        try
-        {
-            Thread.sleep( 2000 );
-        }
-        catch ( InterruptedException e )
-        {
-            // best effort
-        }
-
         return false;
     }
 }
diff --git a/enterprise/causal-clustering/src/test/java/org/neo4j/causalclustering/PortRepository.java b/enterprise/causal-clustering/src/test/java/org/neo4j/causalclustering/PortRepository.java
@@ -26,26 +26,30 @@
 import java.nio.file.FileAlreadyExistsException;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.util.Random;
 
 public class PortRepository
 {
-    private final Path directory;
+    private static final Random RANDOM = new Random();
 
-    private int currentPort;
+    private final Path directory;
+    private final int lowestPort;
 
-    public PortRepository( Path directory, int initialPort )
+    public PortRepository( Path directory, int lowestPort )
     {
         this.directory = directory;
-
+        this.lowestPort = lowestPort;
-        this.currentPort = initialPort;
     }
 
     // synchronize between threads in this JVM
     public synchronized int reserveNextPort( String trace )
     {
-        while ( currentPort <= EphemeralPortMaximum )
+        // if we do not find one after trying 100 times, bail out
+        for ( int i = 0; i < 100; i++ )
         {
-            Path portFilePath = directory.resolve( "port" + currentPort );
+            int port = lowestPort + RANDOM.nextInt( PortConstants.EphemeralPortMaximum - lowestPort );
+
+            Path portFilePath = directory.resolve( "port" + port );
 
             try
             {
@@ -57,11 +61,11 @@ public synchronized int reserveNextPort( String trace )
                     fileOutputStream.flush();
                 }
 
-                return currentPort++;
+                return port;
             }
             catch ( FileAlreadyExistsException e )
             {
-                currentPort++;
+                // try again
             }
             catch ( IOException e )
             {