org.apache.hadoop.chukwa.datacollection.controller

Class ChukwaAgentController

java.lang.Object

org.apache.hadoop.chukwa.datacollection.controller.ChukwaAgentController

public class ChukwaAgentController
extends Object

A convenience library for applications to communicate to the ChukwaAgent. Can be used to register and unregister new Adaptors. Also contains functions for applications to use for handling log rations.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	ChukwaAgentController.AddAdaptorTask

Field Summary

Fields

Modifier and Type	Field and Description
static String	CharFileTailUTF8
static String	CharFileTailUTF8NewLineEscaped

Constructor Summary

Constructors

Constructor and Description
ChukwaAgentController()
ChukwaAgentController(String hostname, int portno)

Method Summary

Modifier and Type	Method and Description
String	add(String adaptorName, String type, String params, long offset) Registers a new adaptor.
String	addByName(String adaptorID, String adaptorName, String type, String params, long offset, long numRetries, long retryInterval) Registers a new adaptor.
String	addFile(String appType, String filename)
String	addFile(String appType, String filename, long numRetries, long retryInterval) Registers a new "LineFileTailUTF8" adaptor and starts it at offset 0.
boolean	isFilePaused(String appType, String filename)
static void	main(String[] args)
Collection<String>	pauseFile(String appType, String filename) Pause all active adaptors of the default file tailing type who are tailing this file This means we actually stop the adaptor and it goes away forever, but we store it state so that we can re-launch a new adaptor with the same state later.
org.apache.hadoop.chukwa.datacollection.controller.ChukwaAgentController.Adaptor	remove(String adaptorID)
void	remove(String className, String appType, String filename)
void	removeAll()
void	removeFile(String appType, String filename)
void	removeInstanceAdaptors()
Collection<String>	resumeFile(String appType, String filename) Resume all adaptors for this filename that have been paused

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

CharFileTailUTF8

public static final String CharFileTailUTF8

See Also:

Constant Field Values

CharFileTailUTF8NewLineEscaped

public static final String CharFileTailUTF8NewLineEscaped

See Also:

Constant Field Values

Constructor Detail

ChukwaAgentController

public ChukwaAgentController()

ChukwaAgentController

public ChukwaAgentController(String hostname,
                             int portno)

Method Detail

add

public String add(String adaptorName,
                  String type,
                  String params,
                  long offset)

Registers a new adaptor. Makes no guarantee about success. On failure, we print a message to stderr and ignore silently so that an application doesn't crash if it's attempt to register an adaptor fails. This call does not retry a conection. for that use the overloaded version of this which accepts a time interval and number of retries

Parameters:

adaptorName - is adaptor class name

type - is data type

params - is adaptor specific parameters

offset - is starting sequence id

Returns:

the id number of the adaptor, generated by the agent

addByName

public String addByName(String adaptorID,
                        String adaptorName,
                        String type,
                        String params,
                        long offset,
                        long numRetries,
                        long retryInterval)

Registers a new adaptor. Makes no guarantee about success. On failure, to connect to server, will retry numRetries times, every retryInterval milliseconds.

Parameters:

adaptorID - is unique adaptor identifier

adaptorName - is adaptor class name

type - is user defined data type name

params - is adaptor specific configuration

offset - is starting sequence id

numRetries - is number of retries

retryInterval - is time between retries

Returns:

the id number of the adaptor, generated by the agent

remove

public org.apache.hadoop.chukwa.datacollection.controller.ChukwaAgentController.Adaptor remove(String adaptorID)
                                                                                        throws IOException

Throws:

IOException

remove

public void remove(String className,
                   String appType,
                   String filename)
            throws IOException

Throws:

IOException

removeAll

public void removeAll()

removeInstanceAdaptors

public void removeInstanceAdaptors()

addFile

public String addFile(String appType,
                      String filename,
                      long numRetries,
                      long retryInterval)

Registers a new "LineFileTailUTF8" adaptor and starts it at offset 0. Checks to see if the file is being watched already, if so, won't register another adaptor with the agent. If you have run the tail adaptor on this file before and rotated or emptied the file you should use pauseFile(String, String) and resumeFile(String, String) which will store the adaptors metadata and re-use them to pick up where it left off.

Parameters:

appType - is user defined name for the data stream

filename - of the file for the tail adaptor to start monitoring

numRetries - is number of retries

retryInterval - is time between retries

Returns:

the id number of the adaptor, generated by the agent

addFile

public String addFile(String appType,
                      String filename)

pauseFile

public Collection<String> pauseFile(String appType,
                                    String filename)
                             throws IOException

Pause all active adaptors of the default file tailing type who are tailing this file This means we actually stop the adaptor and it goes away forever, but we store it state so that we can re-launch a new adaptor with the same state later.

Parameters:

appType - is application type

filename - is file name suffix pattern

Returns:

array of adaptorID numbers which have been created and assigned the state of the formerly paused adaptors

Throws:

IOException - if error pausing adaptors

isFilePaused

public boolean isFilePaused(String appType,
                            String filename)

resumeFile

public Collection<String> resumeFile(String appType,
                                     String filename)
                              throws IOException

Resume all adaptors for this filename that have been paused

Parameters:

appType - is application type

filename - filename by which to lookup adaptors which are paused (and tailing this file)

Returns:

an array of the new adaptor ID numbers which have resumed where the old adaptors left off

Throws:

IOException - if unable to resume all adaptors

removeFile

public void removeFile(String appType,
                       String filename)
                throws IOException

Throws:

IOException

main

public static void main(String[] args)