GetHDFS

Description:

Fetch files from Hadoop Distributed File System (HDFS) into FlowFiles. This Processor will delete the file from HDFS after fetching it.

Tags:

hadoop, HCFS, HDFS, get, fetch, ingest, source, filesystem

Properties:

In the list below, the names of required properties appear in bold. Any other properties (not in bold) are considered optional. The table also indicates any default values, and whether a property supports the NiFi Expression Language.

Display Name	API Name	Default Value	Allowable Values	Description
Hadoop Configuration Resources	Hadoop Configuration Resources			A file or comma separated list of files which contains the Hadoop file system configuration. Without this, Hadoop will search the classpath for a 'core-site.xml' and 'hdfs-site.xml' file or will revert to a default configuration. To use swebhdfs, see 'Additional Details' section of PutHDFS's documentation. This property expects a comma-separated list of file resources. Supports Expression Language: true (will be evaluated using variable registry only)
Kerberos Credentials Service	kerberos-credentials-service		Controller Service API: KerberosCredentialsService Implementation: KeytabCredentialsService	Specifies the Kerberos Credentials Controller Service that should be used for authenticating with Kerberos
Kerberos User Service	kerberos-user-service		Controller Service API: KerberosUserService Implementations: KerberosTicketCacheUserService KerberosKeytabUserService KerberosPasswordUserService	Specifies the Kerberos User Controller Service that should be used for authenticating with Kerberos
Kerberos Principal	Kerberos Principal			Kerberos principal to authenticate as. Requires nifi.kerberos.krb5.file to be set in your nifi.properties Supports Expression Language: true (will be evaluated using variable registry only)
Kerberos Keytab	Kerberos Keytab			Kerberos keytab associated with the principal. Requires nifi.kerberos.krb5.file to be set in your nifi.properties This property requires exactly one file to be provided.. Supports Expression Language: true (will be evaluated using variable registry only)
Kerberos Password	Kerberos Password			Kerberos password associated with the principal. Sensitive Property: true
Kerberos Relogin Period	Kerberos Relogin Period	4 hours		Period of time which should pass before attempting a kerberos relogin. This property has been deprecated, and has no effect on processing. Relogins now occur automatically. Supports Expression Language: true (will be evaluated using variable registry only)
Additional Classpath Resources	Additional Classpath Resources			A comma-separated list of paths to files and/or directories that will be added to the classpath and used for loading native libraries. When specifying a directory, all files with in the directory will be added to the classpath, but further sub-directories will not be included. This property expects a comma-separated list of resources. Each of the resources may be of any of the following types: file, directory.
Directory	Directory			The HDFS directory from which files should be read Supports Expression Language: true (will be evaluated using variable registry only)
Recurse Subdirectories	Recurse Subdirectories	true	true false	Indicates whether to pull files from subdirectories of the HDFS directory
Keep Source File	Keep Source File	false	true false	Determines whether to delete the file from HDFS after it has been successfully transferred. If true, the file will be fetched repeatedly. This is intended for testing only.
File Filter Regex	File Filter Regex			A Java Regular Expression for filtering Filenames; if a filter is supplied then only files whose names match that Regular Expression will be fetched, otherwise all files will be fetched
Filter Match Name Only	Filter Match Name Only	true	true false	If true then File Filter Regex will match on just the filename, otherwise subdirectory names will be included with filename in the regex comparison
Ignore Dotted Files	Ignore Dotted Files	true	true false	If true, files whose names begin with a dot (".") will be ignored
Minimum File Age	Minimum File Age	0 sec		The minimum age that a file must be in order to be pulled; any file younger than this amount of time (based on last modification date) will be ignored
Maximum File Age	Maximum File Age			The maximum age that a file must be in order to be pulled; any file older than this amount of time (based on last modification date) will be ignored
Polling Interval	Polling Interval	0 sec		Indicates how long to wait between performing directory listings
Batch Size	Batch Size	100		The maximum number of files to pull in each iteration, based on run schedule.
IO Buffer Size	IO Buffer Size			Amount of memory to use to buffer file contents during IO. This overrides the Hadoop Configuration
Compression codec	Compression codec	NONE	NONE DEFAULT BZIP GZIP LZ4 LZO SNAPPY AUTOMATIC	No Description Provided.

Relationships:

Name	Description
success	All files retrieved from HDFS are transferred to this relationship

Reads Attributes:

None specified.

Writes Attributes:

Name	Description
filename	The name of the file that was read from HDFS.
path	The path is set to the relative path of the file's directory on HDFS. For example, if the Directory property is set to /tmp, then files picked up from /tmp will have the path attribute set to "./". If the Recurse Subdirectories property is set to true and a file is picked up from /tmp/abc/1/2/3, then the path attribute will be set to "abc/1/2/3".

State management:

This component does not store state.

Restricted:

Required Permission	Explanation
read distributed filesystem	Provides operator the ability to retrieve any file that NiFi has access to in HDFS or the local filesystem.
write distributed filesystem	Provides operator the ability to delete any file that NiFi has access to in HDFS or the local filesystem.

Input requirement:

This component does not allow an incoming relationship.

System Resource Considerations: