ListAzureBlobStorage_v12

Description:

Lists blobs in an Azure Blob Storage container. Listing details are attached to an empty FlowFile for use with FetchAzureBlobStorage. 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. The processor uses Azure Blob Storage client library v12.

Tags:

azure, microsoft, cloud, storage, blob

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
Storage Credentialsstorage-credentials-serviceController Service API:
AzureStorageCredentialsService_v12
Implementation: AzureStorageCredentialsControllerService_v12
Controller Service used to obtain Azure Blob Storage Credentials.
Container Namecontainer-nameName of the Azure storage container. In case of PutAzureBlobStorage processor, container can be created if it does not exist.
Supports Expression Language: true (will be evaluated using variable registry only)
Blob Name Prefixblob-name-prefixSearch prefix for listing
Supports Expression Language: true (will be evaluated using variable registry only)
Record Writerrecord-writerController Service API:
RecordSetWriterFactory
Implementations: RecordSetWriterLookup
XMLRecordSetWriter
FreeFormTextRecordSetWriter
CSVRecordSetWriter
ScriptedRecordSetWriter
AvroRecordSetWriter
JsonRecordSetWriter
ParquetRecordSetWriter
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.
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.
Specify how to determine new/updated entities. See each strategy descriptions for detail.
Entity Tracking State Cacheet-state-cacheController Service API:
DistributedMapCacheClient
Implementations: RedisDistributedMapCacheClientService
HBase_2_ClientMapCacheService
HBase_1_1_2_ClientMapCacheService
CouchbaseMapCacheClient
CassandraDistributedMapCache
DistributedMapCacheClientService
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.

This Property is only considered if the [Listing Strategy] Property has a value of "Tracking Entities".
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)

This Property is only considered if the [Listing Strategy] Property has a value of "Tracking Entities".
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.

This Property is only considered if the [Listing Strategy] Property has a value of "Tracking Entities".
Minimum File AgeMinimum File Age0 secThe minimum age that a file must be in order to be pulled; any file younger than this amount of time (according to last modification date) will be ignored
Maximum File AgeMaximum File AgeThe maximum age that a file must be in order to be pulled; any file older than this amount of time (according to last modification date) will be ignored
Minimum File SizeMinimum File Size0 BThe minimum size that a file must be in order to be pulled
Maximum File SizeMaximum File SizeThe maximum size that a file can be in order to be pulled
Proxy Configuration Serviceproxy-configuration-serviceController Service API:
ProxyConfigurationService
Implementation: StandardProxyConfigurationService
Specifies the Proxy Configuration Controller Service to proxy network requests. Supported proxies: SOCKS, HTTP In case of SOCKS, it is not guaranteed that the selected SOCKS Version will be used by the processor.

Relationships:

NameDescription
successAll FlowFiles that are received are routed to success

Reads Attributes:

None specified.

Writes Attributes:

NameDescription
azure.containerThe name of the Azure Blob Storage container
azure.blobnameThe name of the blob on Azure Blob Storage
azure.primaryUriPrimary location of the blob
azure.etagETag of the blob
azure.blobtypeType of the blob (either BlockBlob, PageBlob or AppendBlob)
mime.typeMIME Type of the content
langLanguage code for the content
azure.timestampTimestamp of the blob
azure.lengthLength of the blob

State management:

ScopeDescription
CLUSTERAfter performing a listing of blobs, the timestamp of the newest blob is stored if 'Tracking Timestamps' Listing Strategy is in use (by default). This allows the Processor to list only blobs 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 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:

None specified.

See Also:

FetchAzureBlobStorage_v12, PutAzureBlobStorage_v12, DeleteAzureBlobStorage_v12