org.apache.hadoop.registry.client.binding
Class RegistryUtils

java.lang.Object
  org.apache.hadoop.registry.client.binding.RegistryUtils

@InterfaceAudience.Public
@InterfaceStability.Evolving
public class RegistryUtils
extends Object

Utility methods for working with a registry.

Constructor Summary

RegistryUtils()

Method Summary

static String	componentListPath(String user, String serviceClass, String serviceName) Create a path for listing components under a service
static String	componentPath(String user, String serviceClass, String serviceName, String componentName) Create the path to a service record for a component
static String	convertUsername(String username) Convert the username to that which can be used for registry entries.
static String	currentUser() Get the current user path formatted for the registry
static Map<String,ServiceRecord>	extractServiceRecords(RegistryOperations operations, String parentpath) Extract all service records under a list of stat operations...this non-atomic action skips entries that are too short or simply not matching.
static Map<String,ServiceRecord>	extractServiceRecords(RegistryOperations operations, String parentpath, Collection<RegistryPathStatus> stats) Extract all service records under a list of stat operations...this skips entries that are too short or simply not matching
static Map<String,ServiceRecord>	extractServiceRecords(RegistryOperations operations, String parentpath, Map<String,RegistryPathStatus> stats) Extract all service records under a list of stat operations...this non-atomic action skips entries that are too short or simply not matching.
static String	getCurrentUsernameUnencoded(String env_hadoop_username) Get the current username, using the value of the parameter env_hadoop_username if it is set on an insecure cluster.
static String	homePathForCurrentUser() Get the home path of the current user.
static String	homePathForUser(String username) Buld the user path -switches to the system path if the user is "".
static Map<String,ServiceRecord>	listServiceRecords(RegistryOperations registryOperations, String path) List service records directly under a path
static String	serviceclassPath(String user, String serviceClass) Create a service classpath
static String	servicePath(String user, String serviceClass, String serviceName) Create a path to a service under a user & service class
static Map<String,RegistryPathStatus>	statChildren(RegistryOperations registryOperations, String path) List children of a directory and retrieve their RegistryPathStatus values.

Methods inherited from class java.lang.Object

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

Constructor Detail

RegistryUtils

public RegistryUtils()

Method Detail

homePathForUser

public static String homePathForUser(String username)

Buld the user path -switches to the system path if the user is "". It also cross-converts the username to ascii via punycode

Parameters:

username - username or ""

Returns:

the path to the user

convertUsername

public static String convertUsername(String username)

Convert the username to that which can be used for registry entries. Lower cases it, Strip the kerberos realm off a username if needed, and any "/" hostname entries

Parameters:

username - user

Returns:

the converted username

serviceclassPath

public static String serviceclassPath(String user,
                                      String serviceClass)

Create a service classpath

Parameters:

user - username or ""

serviceClass - service name

Returns:

a full path

servicePath

public static String servicePath(String user,
                                 String serviceClass,
                                 String serviceName)

Create a path to a service under a user & service class

Parameters:

user - username or ""

serviceClass - service name

serviceName - service name unique for that user & service class

Returns:

a full path

componentListPath

public static String componentListPath(String user,
                                       String serviceClass,
                                       String serviceName)

Create a path for listing components under a service

Parameters:

user - username or ""

serviceClass - service name

serviceName - service name unique for that user & service class

Returns:

a full path

componentPath

public static String componentPath(String user,
                                   String serviceClass,
                                   String serviceName,
                                   String componentName)

Create the path to a service record for a component

Parameters:

user - username or ""

serviceClass - service name

serviceName - service name unique for that user & service class

componentName - unique name/ID of the component

Returns:

a full path

listServiceRecords

public static Map<String,ServiceRecord> listServiceRecords(RegistryOperations registryOperations,
                                                           String path)
                                                    throws IOException

List service records directly under a path

Parameters:

registryOperations - registry operations instance

path - path to list

Returns:

a mapping of the service records that were resolved, indexed by their full path

Throws:

IOException

statChildren

public static Map<String,RegistryPathStatus> statChildren(RegistryOperations registryOperations,
                                                          String path)
                                                   throws org.apache.hadoop.fs.PathNotFoundException,
                                                          InvalidPathnameException,
                                                          IOException

List children of a directory and retrieve their RegistryPathStatus values.

This is not an atomic operation; A child may be deleted during the iteration through the child entries. If this happens, the PathNotFoundException is caught and that child entry ommitted.

Parameters:

path - path

Returns:

a possibly empty map of child entries listed by their short name.

Throws:

org.apache.hadoop.fs.PathNotFoundException - path is not in the registry.

InvalidPathnameException - the path is invalid.

IOException - Any other IO Exception

homePathForCurrentUser

public static String homePathForCurrentUser()

Get the home path of the current user.

In an insecure cluster, the environment variable HADOOP_USER_NAME is queried first.

This means that in a YARN container where the creator set this environment variable to propagate their identity, the defined user name is used in preference to the actual user.

In a secure cluster, the kerberos identity of the current user is used.

Returns:

a path for the current user's home dir.

Throws:

RuntimeException - if the current user identity cannot be determined from the OS/kerberos.

getCurrentUsernameUnencoded

public static String getCurrentUsernameUnencoded(String env_hadoop_username)

Get the current username, using the value of the parameter env_hadoop_username if it is set on an insecure cluster. This ensures that the username propagates correctly across processes started by YARN.

This method is primarly made visible for testing.

Parameters:

env_hadoop_username - the environment variable

Returns:

the selected username

Throws:

RuntimeException - if there is a problem getting the short user name of the current user.

currentUser

public static String currentUser()

Get the current user path formatted for the registry

In an insecure cluster, the environment variable HADOOP_USER_NAME is queried first.

This means that in a YARN container where the creator set this environment variable to propagate their identity, the defined user name is used in preference to the actual user.

In a secure cluster, the kerberos identity of the current user is used.

Returns:

the encoded shortname of the current user

Throws:

RuntimeException - if the current user identity cannot be determined from the OS/kerberos.

extractServiceRecords

public static Map<String,ServiceRecord> extractServiceRecords(RegistryOperations operations,
                                                              String parentpath,
                                                              Collection<RegistryPathStatus> stats)
                                                       throws IOException

Extract all service records under a list of stat operations...this skips entries that are too short or simply not matching

Parameters:

operations - operation support for fetches

parentpath - path of the parent of all the entries

stats - Collection of stat results

Returns:

a possibly empty map of fullpath:record.

Throws:

IOException - for any IO Operation that wasn't ignored.

extractServiceRecords

public static Map<String,ServiceRecord> extractServiceRecords(RegistryOperations operations,
                                                              String parentpath,
                                                              Map<String,RegistryPathStatus> stats)
                                                       throws IOException

Extract all service records under a list of stat operations...this non-atomic action skips entries that are too short or simply not matching.

Parameters:

operations - operation support for fetches

parentpath - path of the parent of all the entries

Returns:

a possibly empty map of fullpath:record.

Throws:

IOException - for any IO Operation that wasn't ignored.

extractServiceRecords

public static Map<String,ServiceRecord> extractServiceRecords(RegistryOperations operations,
                                                              String parentpath)
                                                       throws IOException

Extract all service records under a list of stat operations...this non-atomic action skips entries that are too short or simply not matching.

Parameters:

operations - operation support for fetches

parentpath - path of the parent of all the entries

Returns:

a possibly empty map of fullpath:record.

Throws:

IOException - for any IO Operation that wasn't ignored.