ListAzureBlobStorage

Description:

Lists blobs in an Azure 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.

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, whether a property supports the NiFi Expression Language, and whether a property is considered "sensitive", meaning that its value will be encrypted. Before entering a value in a sensitive property, ensure that the nifi.properties file has an entry for the property nifi.sensitive.props.key.

NameDefault ValueAllowable ValuesDescription
Listing Strategytimestamps
  • 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.
  • 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 'Tracing Timestamps'. 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.
Specify how to determine new/updated entities. See each strategy descriptions for detail.
Container NameName of the Azure storage container
Supports Expression Language: true (will be evaluated using variable registry only)
SAS TokenShared Access Signature token, including the leading '?'. Specify either SAS Token (recommended) or Account Key. There are certain risks in allowing the SAS token to be stored as a flowfile attribute. While it does provide for a more flexible flow by allowing the account name to be fetched dynamically from a flowfile attribute, care must be taken to restrict access to the event provenance data (e.g. by strictly controlling the policies governing provenance for this Processor). In addition, the provenance repositories may be put on encrypted disk partitions.
Sensitive Property: true
Supports Expression Language: true (will be evaluated using variable registry only)
Storage Account NameThe storage account name. There are certain risks in allowing the account name to be stored as a flowfile attribute. While it does provide for a more flexible flow by allowing the account name to be fetched dynamically from a flowfile attribute, care must be taken to restrict access to the event provenance data (e.g. by strictly controlling the policies governing provenance for this Processor). In addition, the provenance repositories may be put on encrypted disk partitions.
Sensitive Property: true
Supports Expression Language: true (will be evaluated using variable registry only)
Storage Account KeyThe storage account key. This is an admin-like password providing access to every container in this account. It is recommended one uses Shared Access Signature (SAS) token instead for fine-grained control with policies. There are certain risks in allowing the account key to be stored as a flowfile attribute. While it does provide for a more flexible flow by allowing the account key to be fetched dynamically from a flow file attribute, care must be taken to restrict access to the event provenance data (e.g. by strictly controlling the policies governing provenance for this Processor). In addition, the provenance repositories may be put on encrypted disk partitions.
Sensitive Property: true
Supports Expression Language: true (will be evaluated using variable registry only)
PrefixSearch prefix for listing
Supports Expression Language: true (will be evaluated using variable registry only)
Proxy Configuration ServiceController Service API:
ProxyConfigurationService
Implementation: StandardProxyConfigurationService
Specifies the Proxy Configuration Controller Service to proxy network requests. Supported proxies: HTTP, SOCKS
Entity Tracking State CacheController Service API:
DistributedMapCacheClient
Implementations: DistributedMapCacheClientService
RedisDistributedMapCacheClientService
CouchbaseMapCacheClient
HBase_1_1_2_ClientMapCacheService
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 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 Targetall
  • 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.

Relationships:

NameDescription
successAll FlowFiles that are received are routed to success

Reads Attributes:

None specified.

Writes Attributes:

NameDescription
azure.containerThe name of the Azure container
azure.blobnameThe name of the Azure blob
azure.primaryUriPrimary location for blob content
azure.secondaryUriSecondary location for blob content
azure.etagEtag for the Azure blob
azure.lengthLength of the blob
azure.timestampThe timestamp in Azure for the blob
mime.typeMimeType of the content
langLanguage code for the content
azure.blobtypeThis is the type of blob and can be either page or block type

State management:

ScopeDescription
CLUSTERAfter performing a listing of blobs, the timestamp of the newest blob is stored. 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, PutAzureBlobStorage, DeleteAzureBlobStorage