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https://issues.apache.org/jira/browse/BEAM-4828?focusedWorklogId=132813&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-132813
]
ASF GitHub Bot logged work on BEAM-4828:
----------------------------------------
Author: ASF GitHub Bot
Created on: 09/Aug/18 03:21
Start Date: 09/Aug/18 03:21
Worklog Time Spent: 10m
Work Description: rangadi commented on a change in pull request #6101:
[BEAM-4828] Add Amazon SqsIO
URL: https://github.com/apache/beam/pull/6101#discussion_r208796453
##########
File path:
sdks/java/io/amazon-web-services/src/main/java/org/apache/beam/sdk/io/aws/sqs/SqsUnboundedReader.java
##########
@@ -0,0 +1,166 @@
+/*
+ * 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.beam.sdk.io.aws.sqs;
+
+import com.amazonaws.services.sqs.model.Message;
+import com.amazonaws.services.sqs.model.MessageSystemAttributeName;
+import com.amazonaws.services.sqs.model.ReceiveMessageRequest;
+import com.amazonaws.services.sqs.model.ReceiveMessageResult;
+import java.io.Serializable;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+import java.util.NoSuchElementException;
+import java.util.Queue;
+import org.apache.beam.sdk.io.UnboundedSource;
+import org.apache.beam.sdk.io.UnboundedSource.CheckpointMark;
+import org.apache.beam.sdk.transforms.windowing.BoundedWindow;
+import org.joda.time.Instant;
+
+class SqsUnboundedReader extends UnboundedSource.UnboundedReader<Message>
implements Serializable {
+
+ public static final int MAX_NUMBER_OF_MESSAGES = 10;
+ private final SqsUnboundedSource source;
+ private Message current;
+ private final Queue<Message> messagesNotYetRead;
+ private List<Message> messagesToDelete;
+ private Instant oldestPendingTimestamp = BoundedWindow.TIMESTAMP_MIN_VALUE;
+
+ public SqsUnboundedReader(SqsUnboundedSource source, SqsCheckpointMark
sqsCheckpointMark) {
+ this.source = source;
+ this.current = null;
+
+ this.messagesNotYetRead = new ArrayDeque<>();
+ this.messagesToDelete = new ArrayList<>();
+
+ if (sqsCheckpointMark != null) {
+ this.messagesToDelete.addAll(sqsCheckpointMark.getMessagesToDelete());
+ }
+ }
+
+ @Override
+ public Instant getWatermark() {
Review comment:
It is a logical stuckness, i.e. if the source does not advance the
watermark, the windows based on data watermark (this is the default) don't
fire. E.g. say a pipeline producing aggregates every minute using 1-minute
fixed windows. A message arrives at 10:30:05 and nothing for next one hour.
When should the aggregates for minute '10:30' be produced? Ideally should be
soon after 10:31:00. What would happen with this source in that case?
Please note that I am not asking this to be fixed, but better to clearly
document the behavior. Managing watermark is one of most important aspects of a
unbounded source.
E.g. while using LogAppendTime in KafkaIO, if a partition is idle, the
watermark for the partition progresses to `(now - 2 seconds)` (see
[here](https://github.com/apache/beam/blob/master/sdks/java/io/kafka/src/main/java/org/apache/beam/sdk/io/kafka/TimestampPolicyFactory.java#L158)).
Justification is that if the partition receives any new message its timestamp
will be in future (2 seconds is to account for any unknown buffering/delays
inside the Kafka server itself).
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Issue Time Tracking
-------------------
Worklog Id: (was: 132813)
Time Spent: 8h 20m (was: 8h 10m)
> Add Amazon SqsIO
> ----------------
>
> Key: BEAM-4828
> URL: https://issues.apache.org/jira/browse/BEAM-4828
> Project: Beam
> Issue Type: New Feature
> Components: io-java-aws
> Reporter: John Rudolf Lewis
> Assignee: John Rudolf Lewis
> Priority: Major
> Time Spent: 8h 20m
> Remaining Estimate: 0h
>
> Add an SQS source
>
> For people who would like to follow progress or help out:
> [https://github.com/JohnRudolfLewis/beam/tree/Add-SqsIO]
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