ListCDPObjectStore

Description:

Retrieves a listing of files from the object store. Each time a listing is performed, the files with the latest timestamp will be excluded and picked up during the next execution of the processor. This is done to ensure that we do not miss any files, or produce duplicates, in the cases where files with the same timestamp are written immediately before and after a single execution of the processor. For each file that is listed, this processor creates a FlowFile that represents the object store file to be fetched in conjunction with FetchCDPObjectStore. This Processor is designed to run on Primary Node only in a cluster. If the primary node changes, the new Primary Node will pick up where the previous node left off without duplicating all of the data. This Processor does not delete any data from the object store.

Additional Details...

Tags:

hadoop, HCFS, HDFS, get, list, ingest, source, filesystem, CDP, GCP, GCS, Google, S3, AWS, ADLS, Azure

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
Storage Location	cdp-storage-location			Use this property to set the storage location in use. Example: 's3a://myBucket/myDirectory'. In case the property is not specified the processor will use the value set in /etc/hadoop/conf/core-site.xml Supports Expression Language: true (will be evaluated using variable registry only)
Directory	Directory			The directory from which files should be read 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
CDP Username	Kerberos Principal			CDP User name. Recommendation is to create a dedicated Machine User in the CDP User Management UI. Supports Expression Language: true (will be evaluated using variable registry only)
CDP Password	Kerberos Password			Workload password associated to your CDP User. You can set it in the CDP User Management UI. If you don't want to use a workload password, you can use the Kerberos Credentials controller service property. Sensitive Property: true
Recurse Subdirectories	Recurse Subdirectories	true	true false	Indicates whether to list files from subdirectories of the HDFS directory
Record Writer	record-writer		Controller Service API: RecordSetWriterFactory Implementations: JsonRecordSetWriter ParquetRecordSetWriter CSVRecordSetWriter ScriptedRecordSetWriter XMLRecordSetWriter FreeFormTextRecordSetWriter AvroRecordSetWriter RecordSetWriterLookup	Specifies the Record Writer to use for creating the listing. If not specified, one FlowFile will be created for each entity that is listed. If the Record Writer is specified, all entities will be written to a single FlowFile.
File Filter	File Filter	[^\.].*		Only files whose names match the given regular expression will be picked up
File Filter Mode	file-filter-mode	Directories and Files	Directories and Files Files Only Full Path	Determines how the regular expression in File Filter will be used when retrieving listings.
Minimum File Age	minimum-file-age			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. Minimum value is 100ms.

Dynamic Properties:

Supports Sensitive Dynamic Properties: No

Dynamic Properties allow the user to specify both the name and value of a property.

Name	Value	Description
A Hadoop client configuration name	The value to set it to	Sets and if already set, overwrites the Hadoop client configuration with the given name. Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)

Relationships:

Name	Description
success	All FlowFiles are transferred to this relationship

Reads Attributes:

None specified.

Writes Attributes:

Name	Description
filename	The name of the file that was read from object store.
path	The path is set to the absolute path of the file's directory on the object store. 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 "/tmp/abc/1/2/3".
objectstore.owner	The user that owns the file in the object store.
objectstore.group	The group that owns the file in the object store.
objectstore.lastModified	The timestamp of when the file in the object store was last modified, as milliseconds since midnight Jan 1, 1970 UTC
objectstore.length	The number of bytes in the file
objectstore.replication	The number of replicas for hte file
objectstore.permissions	The permissions for the file in the object store. This is formatted as 3 characters for the owner, 3 for the group, and 3 for other users. For example rw-rw-r--

State management:

Scope	Description
CLUSTER	After performing a listing of files, the latest timestamp of all the files listed and the latest timestamp of all the files transferred are both stored. This allows the Processor to list only files that have been added or modified after this date the next time that the Processor is run, without having to store all of the actual filenames/paths which could lead to performance problems. State is stored across the cluster so that this Processor can be run on Primary Node only and if a new Primary Node is selected, the new node can pick up where the previous node left off, without duplicating the data.

Scope

Description

CLUSTER

After performing a listing of files, the latest timestamp of all the files listed and the latest timestamp of all the files transferred are both stored. This allows the Processor to list only files that have been added or modified after this date the next time that the Processor is run, without having to store all of the actual filenames/paths which could lead to performance problems. State is stored across the cluster so that this Processor can be run on Primary Node only and if a new Primary Node is selected, the new node can pick up where the previous node left off, without duplicating the data.

Restricted:

This component is not restricted.

Input requirement:

This component does not allow an incoming relationship.

System Resource Considerations: