August 2015
Intermediate to advanced
312 pages
7h 28m
Japanese
Content preview from 初めてのSpark
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
206
10 章 Spark Streaming
10.5.1
コアのー
コアのソースから
DStream
を生成するメソッドは、すべて
StreamingContext
に用意されてい
ます。それらのソースの
1
つであるソケットは、これまでの例ですでに調べました。ここではも
う
2
つ、ファイルと
Akka
のアクターについて議論します。
ファイルのストリーム
Spark
は
Hadoop
と互換性のある任意のファイルシステムからの読み取りをサポートしているの
で、当然ながら
Spark Streaming
は
Hadoop
と互換性のあるファイルシステム内のディレクトリ
に書かれたファイルからストリームを生成できます。この方法でサポートされるバックエンドは多
岐にわたるので、この選択肢は広く使われています。特にログデータの場合、
HDFS
へのコピー
が問題になることはないでしょう。
Spark Streaming
でそういったデータを扱う場合に必要な条件
は、ディレクトリ名に一貫性のあるフォーマットが使われていることと、ファイルが
生成されること（例えば、
Spark
がモニタリングしているディレクトリへファイルを移動させる）
です
†
。
10-4
および
10-5
を
10-29
および
10-30
のように変更すれば、
新しいログファイルがディレクトリに現れるとすぐに処理できるようになります。
10-29
Scala
ー
val logData = ssc.textFileStream(logDirectory) ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.