lib/redis_cluster/pool.rb in redis_cluster-0.3.1 vs lib/redis_cluster/pool.rb in redis_cluster-0.3.2

@@ -52,10 +52,36 @@
 
     def pipelined(args, &block)
       random_node.execute :pipelined, args, &block
     end
 
+    # Implements scan across all nodes in the pool.
+    # Cursors will behave strangely if the node list changes during iteration.
+    def scan(args)
+      scan_cursor = args.first
+      options = args[1] || {}
+      node_cursor, node_index = decode_scan_cursor(scan_cursor)
+      next_node_cursor, result = @nodes[node_index].execute("scan", [node_cursor, options])
+      [encode_next_scan_cursor(next_node_cursor, node_index), result]
+    end
+
     private
+
+    def encode_next_scan_cursor(next_node_cursor, node_index)
+      if next_node_cursor == '0'
+        # '0' indicates the end of iteration.  Advance the node index and
+        # start at the '0' position on the next node.  If this was the last node,
+        # loop around and return '0' to indicate iteration is done.
+        ((node_index + 1) % @nodes.size)
+      else
+        ((next_node_cursor.to_i * @nodes.size) + node_index)
+      end.to_s # Cursors are strings
+    end
+
+    def decode_scan_cursor(cursor)
+      node_cursor, node_index = cursor.to_i.divmod(@nodes.size)
+      [node_cursor.to_s, node_index] # Cursors are strings.
+    end
 
     def node_by(key)
       slot = Slot.slot_by(key)
       @nodes.find { |node| node.has_slot?(slot) }
     end