add topic in debug logs when lookup fails

Author: Guillaume Arnaud

src/main/java/com/github/brainlag/nsq/lookup/DefaultNSQLookup.java

@@ -11,6 +11,7 @@
 import java.net.URL;
 import java.net.URLEncoder;
 import java.util.Set;
+
 public class DefaultNSQLookup implements NSQLookup {
     Set<String> addresses = Sets.newHashSet();
 
@@ -40,12 +41,12 @@ public Set<ServerAddress> lookup(String topic) {
                     addresses.add(address);
                 }
             } catch (IOException e) {
-                LogManager.getLogger(this).warn("Unable to connect to address {}", addr);
+                LogManager.getLogger(this).warn("Unable to connect to address {} for topic {}", addr, topic);
                 LogManager.getLogger(this).debug(e.getMessage());
             }
         }
         if (addresses.isEmpty()) {
-            LogManager.getLogger(this).warn("Unable to connect to any NSQ Lookup servers, servers tried: " + this.addresses.toString());
+            LogManager.getLogger(this).warn("Unable to connect to any NSQ Lookup servers, servers tried: {} on topic: {}", this.addresses, topic);
         }
         return addresses;
     }