[Hadoop Wiki] Update of "Chukwa Adaptors List" by AriRabkin

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The following page has been changed by AriRabkin:
http://wiki.apache.org/hadoop/Chukwa_Adaptors_List

The comment on the change is:
document adaptors more clearly.

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- The following adaptors are built into Chukwa and can be added to the agent using the command line provided after each. These lines can also be added to the conf/initial_adaptors file to have agents run adaptors at startup time.
+ In Chukwa, data is collected by adaptors. Adaptors run inside the agent process, and can be dynamically started and stopped. 
  
- In order to start an adaptor on an agent, you can telnet into the agent (i.e.  and give the "ADD" command line to the agent.
+ (mention that commands can go in initial_adaptors or else at control port)
  
- '''!FileTailer'''
+ The general syntax of the add command is as follows:
  
- '''!FileTailingAdaptor'''
+ {{{add [name =] <adaptor_class_name> <datatype> <adaptor specific params> <initial offset>.}}}
+  
+ The `name` field lets you give this adaptor a meaningful name, in order to stop it later.  If you do not specify a name, Chukwa will autogenerate one by hashing the class name and parameters.  The adaptor class name specifies what adaptor to run.  The `datatype` specifies how to process the collected data.  The initial offset should normally be zero; specifying a nonzero initial offset lets you do advanced things like only processing a portion of a file.  
  
- '''CharFileTailingAdaptorUTF8'''
+ The adaptors built into Chukwa are as follows:
  
- '''CharFileTailingAdaptorUT!F8NewLineEscaped'''  add org.apache.hadoop.chukwa.datacollection.adaptor.filetailer.CharFileTailingAdaptorUT!F8NewLineEscaped SysLog 0 /var/log/messages 0
+ '''!FileAdaptor''':  Push a whole file, as one Chunk, then exit.  Requires file name as parameter.
  
- '''!TerminatorThread'''
+ Example:   {{{add FileTailer }}}
  
+ '''!filetailer.FileTailingAdaptor''': The 
+   Pushes the file as flat bytes, ignoring the content. Useful for streaming binary data.
+ '''!filetailer.CharFileTailingAdaptorUTF8'''
+  The same, but breaking chunks only at carriage returns.  Useful for most ASCII log file formats.
+ '''!filetailer.CharFileTailingAdaptorUT!F8NewLineEscaped'''  
+  The same, but breaking chunks only at non-escaped carriage returns.  Useful for pushing Chukwa-formatted log files, where exception stack traces stay in a single chunk.
+