Github user srdo commented on a diff in the pull request:
https://github.com/apache/storm/pull/2538#discussion_r165854399
--- Diff:
external/storm-kafka-client/src/main/java/org/apache/storm/kafka/spout/internal/CommitMetadataManager.java
---
@@ -0,0 +1,90 @@
+/*
+ * Copyright 2018 The Apache Software Foundation.
+ *
+ * Licensed 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.internal;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import java.io.IOException;
+import java.util.Map;
+import org.apache.kafka.clients.consumer.OffsetAndMetadata;
+import org.apache.kafka.common.TopicPartition;
+import org.apache.storm.kafka.spout.KafkaSpout;
+import org.apache.storm.kafka.spout.KafkaSpoutConfig.ProcessingGuarantee;
+import org.apache.storm.task.TopologyContext;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Generates and reads commit metadata.
+ */
+public class CommitMetadataManager {
+
+ private static final ObjectMapper JSON_MAPPER = new ObjectMapper();
+ private static final Logger LOG =
LoggerFactory.getLogger(CommitMetadata.class);
+ // Metadata information to commit to Kafka. It is unique per spout
instance.
+ private final String commitMetadata;
+ private final ProcessingGuarantee processingGuarantee;
+ private final TopologyContext context;
+
+ /**
+ * Create a manager with the given context.
+ */
+ public CommitMetadataManager(TopologyContext context,
ProcessingGuarantee processingGuarantee) {
+ this.context = context;
+ try {
+ commitMetadata = JSON_MAPPER.writeValueAsString(new
CommitMetadata(
+ context.getStormId(), context.getThisTaskId(),
Thread.currentThread().getName()));
+ this.processingGuarantee = processingGuarantee;
+ } catch (JsonProcessingException e) {
+ LOG.error("Failed to create Kafka commit metadata due to JSON
serialization error", e);
+ throw new RuntimeException(e);
+ }
+ }
+
+ /**
+ * Checks if {@link OffsetAndMetadata} was committed by a {@link
KafkaSpout} instance in this topology.
+ *
+ * @param tp The topic partition the commit metadata belongs to.
+ * @param committedOffset {@link OffsetAndMetadata} info committed to
Kafka
+ * @param offsetManagers The offset managers.
+ * @return true if this topology committed this {@link
OffsetAndMetadata}, false otherwise
+ */
+ public boolean isOffsetCommittedByThisTopology(TopicPartition tp,
OffsetAndMetadata committedOffset,
+ Map<TopicPartition, OffsetManager> offsetManagers) {
+ try {
+ if (processingGuarantee == ProcessingGuarantee.AT_LEAST_ONCE
+ && offsetManagers.containsKey(tp)
+ && offsetManagers.get(tp).hasCommitted()) {
+ return true;
+ }
+
+ final CommitMetadata committedMetadata =
JSON_MAPPER.readValue(committedOffset.metadata(), CommitMetadata.class);
+ return
committedMetadata.getTopologyId().equals(context.getStormId());
+ } catch (IOException e) {
+ LOG.warn("Failed to deserialize [{}]. Error likely occurred
because the last commit "
--- End diff --
Yes, I'll update this message
---
