Greg Harris created KAFKA-14789:
-----------------------------------
Summary: Plugin ServiceLoader visibility from isolated plugins is
inconsistent
Key: KAFKA-14789
URL: https://issues.apache.org/jira/browse/KAFKA-14789
Project: Kafka
Issue Type: Improvement
Components: KafkaConnect
Reporter: Greg Harris
Assignee: Greg Harris
1. Since KIP-285 (defining the basic auth extension) the classloading isolation
mechanism has used ServiceLoader to find rest extensions.
2. Since KIP-297 (adding secrets externalization via ConfigProvider)
serviceloading was used to discover ConfigProviders.
3. It was noticed that the isolation mechanism improperly discovered service
loaded plugins and attributed classpath plugins to all isolated plugins. This
was fixed by KAFKA-6991, in which the ConnectRestExtension and ConfigProvider
manifest files are hidden from the isolated plugins, in order to hide them from
the scanning ServiceLoader calls.
4. Since KIP-458 (adding ConnectorConfigOverridePolicy) serviceloading was used
to discover ConnectorConfigOverridePolicy instances, but these manifests were
not hidden from plugin classloaders. ConnectorConfigOverridePolicy objects are
currently mis-attributed, but this has had no ill-effects at this time.
5. With KIP-898, all plugins will be loaded with the ServiceLoader, and so all
other plugins could potentially encounter this mis-attribution bug that was
only resolved for 2 of the plugins in the past.
The current implementation relies on a string equality test to deny reading the
serviceloader manifests that cause mis-attribution, which is a brittle
solution. It was very easy for the person implementing KIP-458 to forget to add
the new class to the manifest denylist, and cause a re-appearance of the
mis-attribution bug.
The denylist approach to preventing mis-attribution also changes the visibility
of classpath plugins from isolated classloaders. We should choose whether the
visibility of classpath plugins is desirable, and either eliminate the denylist
or make it more difficult to get out-of-sync with the current list of plugins.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
