Github user srowen commented on a diff in the pull request:
https://github.com/apache/spark/pull/14731#discussion_r95058521
--- Diff: docs/streaming-programming-guide.md ---
@@ -630,35 +630,106 @@ which creates a DStream from text
data received over a TCP socket connection. Besides sockets, the
StreamingContext API provides
methods for creating DStreams from files as input sources.
-- **File Streams:** For reading data from files on any file system
compatible with the HDFS API (that is, HDFS, S3, NFS, etc.), a DStream can be
created as:
+#### File Streams
+{:.no_toc}
+
+For reading data from files on any file system compatible with the HDFS
API (that is, HDFS, S3, NFS, etc.), a DStream can be created as
+via `StreamingContext.fileStream[KeyClass, ValueClass, InputFormatClass]`.
+
+File streams do not require running a receiver, hence does not require
allocating cores.
- <div class="codetabs">
- <div data-lang="scala" markdown="1">
- streamingContext.fileStream[KeyClass, ValueClass,
InputFormatClass](dataDirectory)
- </div>
- <div data-lang="java" markdown="1">
- streamingContext.fileStream<KeyClass, ValueClass,
InputFormatClass>(dataDirectory);
- </div>
- <div data-lang="python" markdown="1">
- streamingContext.textFileStream(dataDirectory)
- </div>
- </div>
+For simple text files, the easiest method is
`StreamingContext.textFileStream(dataDirectory)`.
- Spark Streaming will monitor the directory `dataDirectory` and process
any files created in that directory (files written in nested directories not
supported). Note that
+<div class="codetabs">
+<div data-lang="scala" markdown="1">
- + The files must have the same data format.
- + The files must be created in the `dataDirectory` by atomically
*moving* or *renaming* them into
- the data directory.
- + Once moved, the files must not be changed. So if the files are
being continuously appended, the new data will not be read.
+{% highlight scala %}
+streamingContext.fileStream[KeyClass, ValueClass,
InputFormatClass](dataDirectory)
+{% endhighlight %}
+For text files
--- End diff --
Space before, and colon at the end of aline?
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