Github user aljoscha commented on a diff in the pull request:
https://github.com/apache/flink/pull/1929#discussion_r61402951
--- Diff:
flink-streaming-java/src/main/java/org/apache/flink/streaming/api/functions/source/FileSplitMonitoringFunction.java
---
@@ -0,0 +1,225 @@
+/*
+ * 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.flink.streaming.api.functions.source;
+
+import org.apache.flink.api.common.io.FileInputFormat;
+import org.apache.flink.configuration.Configuration;
+import org.apache.flink.core.fs.FileInputSplit;
+import org.apache.flink.core.fs.FileStatus;
+import org.apache.flink.core.fs.FileSystem;
+import org.apache.flink.core.fs.Path;
+import org.apache.flink.runtime.JobException;
+import org.apache.flink.util.Preconditions;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.net.URI;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * This is the single (non-parallel) task which monitors a user-provided
path and assigns splits
+ * to downstream tasks for further reading and processing. Which splits
will be further processed
+ * depends on the user-provided {@link
FileSplitMonitoringFunction.WatchType}.
+ */
+public class FileSplitMonitoringFunction<OUT>
+ extends RichSourceFunction<FileInputSplit> {
+
+ private static final long serialVersionUID = 1L;
+
+ private static final Logger LOG =
LoggerFactory.getLogger(FileSplitMonitoringFunction.class);
+
+ /**
+ * Specifies when computation will be triggered.
+ */
+ public enum WatchType {
+ REPROCESS_WITH_APPENDED // Reprocesses the whole file
when new data is appended.
+ }
+
+ /** The path to monitor. */
+ private final String path;
+
+ /** The default parallelism for the job, as this is going to be the
parallelism of the downstream readers. */
+ private final int readerParallelism;
+
+ /** The {@link FileInputFormat} to be read. */
+ private FileInputFormat<OUT> format;
+
+ /** How often to monitor the state of the directory for new data. */
+ private final long interval;
+
+ /** Which new data to process (see {@link WatchType}. */
+ private final WatchType watchType;
+
+ private long globalModificationTime;
+
+ private FilePathFilter pathFilter;
+
+ private volatile boolean isRunning = true;
--- End diff --
In the Kafka source we have it like this as well. I think if it is set in
open this can lead to race conditions with cancel being called at weird places
and stuff. I vaguely remember that that was the reason for why it is like this
in the Kafka source.
---
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.
---
