Github user harshach commented on a diff in the pull request:
https://github.com/apache/storm/pull/1131#discussion_r56409148
--- Diff:
external/storm-kafka-client/src/main/java/org/apache/storm/kafka/spout/KafkaSpoutConfig.java
---
@@ -0,0 +1,298 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.storm.kafka.spout;
+
+import org.apache.kafka.common.serialization.Deserializer;
+
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * KafkaSpoutConfig defines the required configuration to connect a
consumer to a consumer group, as well as the subscribing topics
+ */
+public class KafkaSpoutConfig<K, V> implements Serializable {
+ public static final long DEFAULT_POLL_TIMEOUT_MS = 2_000;
// 2s
+ public static final long DEFAULT_OFFSET_COMMIT_PERIOD_MS = 15_000;
// 15s
+ public static final int DEFAULT_MAX_RETRIES = Integer.MAX_VALUE;
// Retry forever
+ public static final int DEFAULT_MAX_UNCOMMITTED_OFFSETS = 10_000;
// 10,000 records
+
+ // Kafka property names
+ public interface Consumer {
+ String GROUP_ID = "group.id";
+ String BOOTSTRAP_SERVERS = "bootstrap.servers";
+ String ENABLE_AUTO_COMMIT = "enable.auto.commit";
+ String AUTO_COMMIT_INTERVAL_MS = "auto.commit.interval.ms";
+ String KEY_DESERIALIZER = "key.deserializer";
+ String VALUE_DESERIALIZER = "value.deserializer";
+ }
+
+ /**
+ * The offset used by the Kafka spout in the first poll to Kafka
broker. The choice of this parameter will
+ * affect the number of consumer records returned in the first poll.
By default this parameter is set to UNCOMMITTED_EARLIEST. <br/><br/>
+ * The allowed values are EARLIEST, LATEST, UNCOMMITTED_EARLIEST,
UNCOMMITTED_LATEST. <br/>
+ * <ul>
+ * <li>EARLIEST means that the kafka spout polls records starting in
the first offset of the partition, regardless of previous commits</li>
+ * <li>LATEST means that the kafka spout polls records with offsets
greater than the last offset in the partition, regardless of previous
commits</li>
+ * <li>UNCOMMITTED_EARLIEST means that the kafka spout polls records
from the last committed offset, if any.
+ * If no offset has been committed, it behaves as EARLIEST.</li>
+ * <li>UNCOMMITTED_LATEST means that the kafka spout polls records
from the last committed offset, if any.
+ * If no offset has been committed, it behaves as LATEST.</li>
+ * </ul>
+ * */
+ public enum FirstPollOffsetStrategy {
+ EARLIEST,
+ LATEST,
+ UNCOMMITTED_EARLIEST,
+ UNCOMMITTED_LATEST }
+
+ /**
+ * Defines when to poll the next batch of records from Kafka. The
choice of this parameter will affect throughput and the memory
+ * footprint of the Kafka spout. The allowed values are STREAM and
BATCH. STREAM will likely have higher throughput and use more memory
+ * (it stores in memory the entire KafkaRecord,including data). BATCH
will likely have less throughput but also use less memory.
+ * The BATCH behavior is similar to the behavior of the previous Kafka
Spout. De default value is STREAM.
+ * <ul>
+ * <li>STREAM Every periodic call to nextTuple polls a new batch
of records from Kafka as long as the maxUncommittedOffsets
+ * threshold has not yet been reached. When the threshold his
reached, no more records are polled until enough offsets have been
+ * committed, such that the number of pending offsets is less than
maxUncommittedOffsets. See {@link Builder#setMaxUncommittedOffsets(int)}
+ * </li>
+ * <li>BATCH Only polls a new batch of records from kafka once all
the records that came in the previous poll have been acked.</li>
+ * </ul>
+ */
+ public enum PollStrategy {
+ STREAM,
+ BATCH
--- End diff --
@revans2 makes sense. Yes one of the things considered was to make network
call vs in-memory replay. We all agree on failures not-norm and I am +1 on
removing the in-memory replay and instead make a call to broker to replay the
message.
BATCH can go away as well once we fix the in-memory replay. BATCH is there
to mimic the old spout behavior.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastruct...@apache.org or file a JIRA ticket
with INFRA.
---
