C0urante commented on a change in pull request #10549:
URL: https://github.com/apache/kafka/pull/10549#discussion_r615928396



##########
File path: 
connect/runtime/src/main/java/org/apache/kafka/connect/runtime/isolation/DelegatingClassLoader.java
##########
@@ -187,17 +192,24 @@ private static PluginClassLoader newPluginClassLoader(
         );
     }
 
-    private <T> void addPlugins(Collection<PluginDesc<T>> plugins, ClassLoader 
loader) {
+    //visible for testing
+    <T> void addPlugins(Collection<PluginDesc<T>> plugins, ClassLoader loader) 
{
         for (PluginDesc<T> plugin : plugins) {
             String pluginClassName = plugin.className();
             SortedMap<PluginDesc<?>, ClassLoader> inner = 
pluginLoaders.get(pluginClassName);
+            boolean pluginConflict = false;
             if (inner == null) {
                 inner = new TreeMap<>();
                 pluginLoaders.put(pluginClassName, inner);
                 // TODO: once versioning is enabled this line should be moved 
outside this if branch
                 log.info("Added plugin '{}'", pluginClassName);
+            } else {
+                pluginConflict = true;
             }
             inner.put(plugin, loader);
+            if (pluginConflict) {
+                log.error("Detected multiple copies of plugin '{}', one of 
these will be used '{}'", pluginClassName, inner.keySet());
+            }

Review comment:
       Mmmm, I'm not sure we should be making decisions here based on dynamic 
plugin loading for two reasons:
   
   1. This change can be backported to older versions of Connect, which will 
never have that feature.
   2. It's unclear exactly what the mechanism for dynamic plugin loading will 
be, and it's possible that a re-scan of all known plugins after loading has 
taken place (either the initial start load or a subsequent dynamic load at 
runtime) could still be beneficial
   
   Also, it's actually not that uncommon for 3+ copies of the same plugin to 
appear on the plugin path for a worker. For example, some connectors come 
packaged directly with converters; all it takes is at least two such connectors 
and a separately-installed copy of that converter to lead to that number of 
copies.




-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

For queries about this service, please contact Infrastructure at:
us...@infra.apache.org


Reply via email to