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| Code Block | ||||
|---|---|---|---|---|
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/**
* Lookup the current configuration of a connector. This provides the current snapshot of configuration by querying the underlying
* herder. A connector returned by previous invocation of {@link #connectors()} may no longer be available and could result in {@link
* org.apache.kafka.connect.errors.NotFoundException}.
*
* @param connName name of the connector
* @return the configuration of the connector for the connector name
* @throws org.apache.kafka.connect.errors.NotFoundException if the requested connector can't be found
* @throws java.lang.UnsupportedOperationException if the default implementation has not been overridden
*/
default Map<String, String> connectorConfig(String connName) {
throw new UnsupportedOperationException();
}
/**
* Lookup the current task configurations of a connector. This provides the current snapshot of configuration by querying the underlying
* herder. A connector returned by previous invocation of {@link #connectors()} may no longer be available and could result in {@link
* org.apache.kafka.connect.errors.NotFoundException}.
*
* @param connName name of the connector
* @return the configuration for each task ID
* @throws org.apache.kafka.connect.errors.NotFoundException if the requested connector can't be found
* @throws java.lang.UnsupportedOperationException if the default implementation has not been overridden
**/
default Map<Integer, Map<String, String>> taskConfigs(String connName) {
throw new UnsupportedOperationException();
}
/**
* Get the cluster ID of the Kafka cluster backing this Connect cluster.
* @return the cluster ID of the Kafka cluster backing this connect cluster
* @throws java.lang.UnsupportedOperationException if the default implementation has not been overridden
**/
default String kafkaClusterId() {
throw new UnsupportedOperationException();
} |
Proposed Changes
The basic idea here is was to add as much information to the ConnectClusterState interface as is available via the Connect REST API; this includes all currently-available read-only methods of the Herder interface. However, due to lack of a convincing use case, information on task configurations will be left out for now.
For some of these methods, such as connectorConfig(...) and taskConfigs(...), communication with the underlying Herder will be necessary. The return values will reflect the most up-to-date information that the worker has available locally; the herder will not forward requests to the leader of the worker group. An exception will be thrown if the herder is expecting an impending rebalance. This aligns with the behavior of the current ConnectClusterStateImpl class.
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Adding non-default methods to the interface would be a backwards incompatible change for anyone developing their own ConnectClusterState implementation. Adding defaults for these methods, even if they immediately throw exceptions, solves this problem.
Exposing task configurations
Although information on task configurations is readily available from Herder instances, there has yet to be a convincing use case for exposing information on task configurations to REST extensions. This functionality can always be added later in a separate KIP; for now, we'll err on the side of caution and not add support for a feature that may not be used by anyone.
Query the Connect REST API from within the extension itself
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