HDFSPage edited by Ben O'Day
Comment:
update per CAMEL-6867 - using UUID generator for split filenames
Changes (4)
Full ContentHDFS ComponentAvailable as of Camel 2.8 The hdfs component enables you to read and write messages from/to an HDFS file system. HDFS is the distributed file system at the heart of Hadoop. Maven users will need to add the following dependency to their pom.xml for this component: <dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-hdfs</artifactId> <version>x.x.x</version> <!-- use the same version as your Camel core version --> </dependency>
BYTES is also used with everything else, for example, in Camel a file is sent around as an InputStream, int this case is written in a sequence file or a map file as a sequence of bytes. Splitting StrategyIn the current version of Hadoop opening a file in append mode is disabled since it's not very reliable. So, for the moment, it's only possible to create new files. The Camel HDFS endpoint tries to solve this problem in this way:
where <ST> can be:
for example: hdfs://localhost/tmp/simple-file?splitStrategy=IDLE:1000,BYTES:5 it means: a new file is created either when it has been idle for more than 1 second or if more than 5 bytes have been written. So, running hadoop fs -ls /tmp/simple-file you'll find multiple files created named using the UuidGenerator, etc Message HeadersThe following headers are supported by this component: Producer only
Controlling to close file streamAvailable as of Camel 2.10.4 When using the HDFS producer without a split strategy, then the file output stream is by default closed after the write. However you may want to keep the stream open, and only explicitly close the stream later. For that you can use the header HdfsConstants.HDFS_CLOSE (value = "CamelHdfsClose") to control this. Setting this value to a boolean allows you to explicit control whether the stream should be closed or not. Notice this does not apply if you use a split strategy, as there are various strategies that can control when the stream is closed. Using this component in OSGiThis component is fully functional in an OSGi environment, however, it requires some actions from the user. Hadoop uses the thread context class loader in order to load resources. Usually, the thread context classloader will be the bundle class loader of the bundle that contains the routes. So, the default configuration files need to be visible from the bundle class loader. A typical way to deal with it is to keep a copy of core-default.xml in your bundle root. That file can be found in the hadoop-common.jar.
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- [CONF] Apache Camel > HDFS Ben O'Day (Confluence)
- [CONF] Apache Camel > HDFS Ben O'Day (Confluence)
- [CONF] Apache Camel > HDFS Ben O'Day (Confluence)
- [CONF] Apache Camel > HDFS Claus Ibsen (Confluence)