feat(minor): [sc-9450] Add possibility to delete consumer groups.

Sources/Kafka/ForTesting/RDKafkaClient+Group.swift

@@ -79,4 +79,71 @@ extension RDKafkaClient {
             return ret
         }
     }
+
+    /// Delete client consumer groups from the cluster.
+    /// Blocks for a maximum of `timeout` milliseconds.
+    /// - Parameter groups: groups to delete
+    /// - Parameter timeout: timeout
+    /// - Returns: groups that could not be deleted with error message
+    /// - Throws: A ``KafkaError`` if kafka call fails.
+    public func _deleteGroups(_ groups: [String], timeout: Duration) throws -> [(groupId: String, errorMessage: String)] {
+        try withKafkaHandlePointer { kafkaHandle in
+            let delGroups = UnsafeMutablePointer<OpaquePointer?>.allocate(capacity: groups.count)
+
+            for idx in 0..<groups.count {
+                let group = groups[idx]
+                delGroups[idx] = rd_kafka_DeleteGroup_new(group.cString(using: .utf8))
+            }
+
+            defer {
+                rd_kafka_DeleteGroup_destroy_array(delGroups, groups.count)
+                delGroups.deallocate()
+            }
+
+            var adminOptions = rd_kafka_AdminOptions_new(kafkaHandle, RD_KAFKA_ADMIN_OP_DELETEGROUPS)
+            defer { rd_kafka_AdminOptions_destroy(adminOptions) }
+
+            let timeoutMs = Int32(timeout.inMilliseconds)
+            if timeoutMs > 0 {
+                let errorChars = UnsafeMutablePointer<CChar>.allocate(capacity: RDKafkaClient.stringSize)
+                defer { errorChars.deallocate() }
+                let err = rd_kafka_AdminOptions_set_request_timeout(adminOptions, timeoutMs, errorChars, RDKafkaClient.stringSize)
+                if err != RD_KAFKA_RESP_ERR_NO_ERROR {
+                    throw KafkaError.rdKafkaError(wrapping: err, errorMessage: String(cString: errorChars))
+                }
+            }
+
+            let resultQueue = rd_kafka_queue_new(kafkaHandle)
+            defer { rd_kafka_queue_destroy(resultQueue) }
+
+            rd_kafka_DeleteGroups(kafkaHandle, delGroups, groups.count, adminOptions, resultQueue);
+
+            guard let resultEvent = rd_kafka_queue_poll(resultQueue, timeoutMs) else {
+                throw KafkaError.rdKafkaError(errorMessage: "rd_kafka_queue_poll() timed out")
+            }
+            defer { rd_kafka_event_destroy(resultEvent) }
+
+            if rd_kafka_event_error(resultEvent) != RD_KAFKA_RESP_ERR_NO_ERROR {
+                let errorMessage = String(cString: rd_kafka_event_error_string(resultEvent))
+                throw KafkaError.rdKafkaError(wrapping: rd_kafka_event_error(resultEvent), errorMessage: errorMessage)
+            }
+
+            var resultGroupsCnt = 0
+            let resultGroups = rd_kafka_DeleteGroups_result_groups(resultEvent, &resultGroupsCnt);
+            guard let resultGroups else {
+                return []
+            }
+
+            var ret = [(String, String)]()
+            for idx in 0..<resultGroupsCnt {
+                if let groupResultError = rd_kafka_group_result_error(resultGroups[idx]) {
+                    let groupResultName = String(cString: rd_kafka_group_result_name(groupResultError))
+                    let errorString = String(cString: rd_kafka_error_string(groupResultError))
+                    ret.append((groupResultName, errorString))
+                }
+            }
+
+            return ret
+        }
+    }
 }