ListFTP

Description:

Performs a listing of the files residing on an FTP server. For each file that is found on the remote server, a new FlowFile will be created with the filename attribute set to the name of the file on the remote server. This can then be used in conjunction with FetchFTP in order to fetch those files.

Additional Details...

Tags:

list, ftp, remote, ingest, source, input, files

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 NameAPI NameDefault ValueAllowable ValuesDescription
Listing Strategylisting-strategyTracking Timestamps
  • Tracking Timestamps This strategy tracks the latest timestamp of listed entity to determine new/updated entities. Since it only tracks few timestamps, it can manage listing state efficiently. However, any newly added, or updated entity having timestamp older than the tracked latest timestamp can not be picked by this strategy. For example, such situation can happen in a file system if a file with old timestamp is copied or moved into the target directory without its last modified timestamp being updated. Also may miss files when multiple subdirectories are being written at the same time while listing is running.
  • Tracking Entities This strategy tracks information of all the listed entities within the latest 'Entity Tracking Time Window' to determine new/updated entities. This strategy can pick entities having old timestamp that can be missed with 'Tracking Timestamps'. Works even when multiple subdirectories are being written at the same time while listing is running. However additional DistributedMapCache controller service is required and more JVM heap memory is used. See the description of 'Entity Tracking Time Window' property for further details on how it works.
  • No Tracking This strategy lists an entity without any tracking. The same entity will be listed each time on executing this processor. It is recommended to change the default run schedule value. Any property that related to the persisting state will be disregarded.
  • Time Window This strategy uses a sliding time window. The window starts where the previous window ended and ends with the 'current time'. One cycle will list files with modification time falling within the time window. Works even when multiple subdirectories are being written at the same time while listing is running. IMPORTANT: This strategy works properly only if the time on both the system hosting NiFi and the one hosting the files are accurate.
Specify how to determine new/updated entities. See each strategy descriptions for detail.
HostnameHostnameThe fully qualified hostname or IP address of the remote system
Supports Expression Language: true (will be evaluated using variable registry only)
PortPort21The port to connect to on the remote host to fetch the data from
Supports Expression Language: true (will be evaluated using variable registry only)
UsernameUsernameUsername
Supports Expression Language: true (will be evaluated using variable registry only)
PasswordPasswordPassword for the user account
Sensitive Property: true
Supports Expression Language: true (will be evaluated using variable registry only)
Remote PathRemote Path.The path on the remote system from which to pull or push files
Supports Expression Language: true (will be evaluated using variable registry only)
Record Writerrecord-writerController Service API:
RecordSetWriterFactory
Implementations: JsonRecordSetWriter
RecordSetWriterLookup
AvroRecordSetWriter
XMLRecordSetWriter
FreeFormTextRecordSetWriter
CSVRecordSetWriter
ParquetRecordSetWriter
ScriptedRecordSetWriter		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 instead of adding attributes to individual FlowFiles.
Distributed Cache ServiceDistributed Cache ServiceController Service API:
DistributedMapCacheClient
Implementations: CassandraDistributedMapCache
SimpleRedisDistributedMapCacheClientService
CouchbaseMapCacheClient
HBase_2_ClientMapCacheService
DistributedMapCacheClientService
RedisDistributedMapCacheClientService
HazelcastMapCacheClient		NOTE: This property is used merely for migration from old NiFi version before state management was introduced at version 0.5.0. The stored value in the cache service will be migrated into the state when this processor is started at the first time. The specified Controller Service was used to maintain state about what had been pulled from the remote server so that if a new node begins pulling data, it won't duplicate all of the work that has been done. If not specified, the information was not shared across the cluster. This property did not need to be set for standalone instances of NiFi but was supposed to be configured if NiFi had been running within a cluster.
Search RecursivelySearch Recursivelyfalse
  • true
  • false
If true, will pull files from arbitrarily nested subdirectories; otherwise, will not traverse subdirectories
Follow symlinkfollow-symlinkfalse
  • true
  • false
If true, will pull even symbolic files and also nested symbolic subdirectories; otherwise, will not read symbolic files and will not traverse symbolic link subdirectories
File Filter RegexFile Filter RegexProvides a Java Regular Expression for filtering Filenames; if a filter is supplied, only files whose names match that Regular Expression will be fetched
Path Filter RegexPath Filter RegexWhen Search Recursively is true, then only subdirectories whose path matches the given Regular Expression will be scanned
Ignore Dotted FilesIgnore Dotted Filestrue
  • true
  • false
If true, files whose names begin with a dot (".") will be ignored
Remote Poll Batch SizeRemote Poll Batch Size5000The value specifies how many file paths to find in a given directory on the remote system when doing a file listing. This value in general should not need to be modified but when polling against a remote system with a tremendous number of files this value can be critical. Setting this value too high can result very poor performance and setting it too low can cause the flow to be slower than normal.
Connection TimeoutConnection Timeout30 secAmount of time to wait before timing out while creating a connection
Data TimeoutData Timeout30 secWhen transferring a file between the local and remote system, this value specifies how long is allowed to elapse without any data being transferred between systems
Connection ModeConnection ModePassive
  • Active
  • Passive
The FTP Connection Mode
Transfer ModeTransfer ModeBinary
  • Binary
  • ASCII
The FTP Transfer Mode
Proxy Configuration Serviceproxy-configuration-serviceController Service API:
ProxyConfigurationService
Implementation: StandardProxyConfigurationService		Specifies the Proxy Configuration Controller Service to proxy network requests. If set, it supersedes proxy settings configured per component. Supported proxies: HTTP + AuthN, SOCKS + AuthN
Proxy TypeProxy TypeDIRECT
  • DIRECT
  • HTTP
  • SOCKS
Proxy type used for file transfers
Proxy HostProxy HostThe fully qualified hostname or IP address of the proxy server
Supports Expression Language: true (will be evaluated using variable registry only)
Proxy PortProxy PortThe port of the proxy server
Supports Expression Language: true (will be evaluated using variable registry only)
Http Proxy UsernameHttp Proxy UsernameHttp Proxy Username
Supports Expression Language: true (will be evaluated using variable registry only)
Http Proxy PasswordHttp Proxy PasswordHttp Proxy Password
Sensitive Property: true
Supports Expression Language: true (will be evaluated using variable registry only)
Internal Buffer SizeInternal Buffer Size16KBSet the internal buffer size for buffered data streams
Target System Timestamp Precisiontarget-system-timestamp-precisionAuto Detect
  • Auto Detect Automatically detect time unit deterministically based on candidate entries timestamp. Please note that this option may take longer to list entities unnecessarily, if none of entries has a precise precision timestamp. E.g. even if a target system supports millis, if all entries only have timestamps without millis, such as '2017-06-16 09:06:34.000', then its precision is determined as 'seconds'.
  • Milliseconds This option provides the minimum latency for an entry from being available to being listed if target system supports millis, if not, use other options.
  • Seconds For a target system that does not have millis precision, but has in seconds.
  • Minutes For a target system that only supports precision in minutes.
Specify timestamp precision at the target system. Since this processor uses timestamp of entities to decide which should be listed, it is crucial to use the right timestamp precision.
Entity Tracking State Cacheet-state-cacheController Service API:
DistributedMapCacheClient
Implementations: CassandraDistributedMapCache
SimpleRedisDistributedMapCacheClientService
CouchbaseMapCacheClient
HBase_2_ClientMapCacheService
DistributedMapCacheClientService
RedisDistributedMapCacheClientService
HazelcastMapCacheClient		Listed entities are stored in the specified cache storage so that this processor can resume listing across NiFi restart or in case of primary node change. 'Tracking Entities' strategy require tracking information of all listed entities within the last 'Tracking Time Window'. To support large number of entities, the strategy uses DistributedMapCache instead of managed state. Cache key format is 'ListedEntities::{processorId}(::{nodeId})'. If it tracks per node listed entities, then the optional '::{nodeId}' part is added to manage state separately. E.g. cluster wide cache key = 'ListedEntities::8dda2321-0164-1000-50fa-3042fe7d6a7b', per node cache key = 'ListedEntities::8dda2321-0164-1000-50fa-3042fe7d6a7b::nifi-node3' The stored cache content is Gzipped JSON string. The cache key will be deleted when target listing configuration is changed. Used by 'Tracking Entities' strategy.
Entity Tracking Time Windowet-time-window3 hoursSpecify how long this processor should track already-listed entities. 'Tracking Entities' strategy can pick any entity whose timestamp is inside the specified time window. For example, if set to '30 minutes', any entity having timestamp in recent 30 minutes will be the listing target when this processor runs. A listed entity is considered 'new/updated' and a FlowFile is emitted if one of following condition meets: 1. does not exist in the already-listed entities, 2. has newer timestamp than the cached entity, 3. has different size than the cached entity. If a cached entity's timestamp becomes older than specified time window, that entity will be removed from the cached already-listed entities. Used by 'Tracking Entities' strategy.
Supports Expression Language: true (will be evaluated using variable registry only)
Entity Tracking Initial Listing Targetet-initial-listing-targetAll Available
  • Tracking Time Window Ignore entities having timestamp older than the specified 'Tracking Time Window' at the initial listing activity.
  • All Available Regardless of entities timestamp, all existing entities will be listed at the initial listing activity.
Specify how initial listing should be handled. Used by 'Tracking Entities' strategy.
Use UTF-8 Encodingftp-use-utf8false
  • true
  • false
Tells the client to use UTF-8 encoding when processing files and filenames. If set to true, the server must also support UTF-8 encoding.

Relationships:

NameDescription
successAll FlowFiles that are received are routed to success

Reads Attributes:

None specified.

Writes Attributes:

NameDescription
ftp.remote.hostThe hostname of the FTP Server
ftp.remote.portThe port that was connected to on the FTP Server
ftp.listing.userThe username of the user that performed the FTP Listing
file.ownerThe numeric owner id of the source file
file.groupThe numeric group id of the source file
file.permissionsThe read/write/execute permissions of the source file
file.sizeThe number of bytes in the source file
file.lastModifiedTimeThe timestamp of when the file in the filesystem waslast modified as 'yyyy-MM-dd'T'HH:mm:ssZ'
filenameThe name of the file on the FTP Server
pathThe fully qualified name of the directory on the FTP Server from which the file was pulled

State management:

ScopeDescription
CLUSTERAfter performing a listing of files, the timestamp of the newest file is 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. 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 will not duplicate the data that was listed by the previous Primary Node.

Restricted:

This component is not restricted.

Input requirement:

This component does not allow an incoming relationship.

System Resource Considerations:

None specified.

See Also:

FetchFTP, GetFTP, PutFTP