Retrieves a listing of objects from an GCS bucket. For each object that is listed, creates a FlowFile that represents the object so that it can be fetched in conjunction with FetchGCSObject. 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.


google cloud, google, storage, gcs, list


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 file has an entry for the property nifi.sensitive.props.key.

NameDefault ValueAllowable ValuesDescription
GCP Credentials Provider ServiceController Service API:
Implementation: GCPCredentialsControllerService
The Controller Service used to obtain Google Cloud Platform credentials.
Project IDGoogle Cloud Project ID
Number of retries6How many retry attempts should be made before routing to the failure relationship.
Proxy hostIP or hostname of the proxy to be used. You might need to set the following properties in bootstrap for https proxy usage: -Djdk.http.auth.tunneling.disabledSchemes= -Djdk.http.auth.proxying.disabledSchemes=
Proxy portProxy port number
Http Proxy UsernameHttp Proxy Username
Supports Expression Language: true (will be evaluated using variable registry only)
Http Proxy PasswordHttp Proxy Password
Sensitive Property: true
Supports Expression Language: true (will be evaluated using variable registry only)
Proxy Configuration ServiceController Service API:
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
BucketBucket of the object.
PrefixThe prefix used to filter the object list. In most cases, it should end with a forward slash ('/').
Use Generationsfalse
  • true
  • false
Specifies whether to use GCS Generations, if applicable. If false, only the latest version of each object will be returned.


successFlowFiles are routed to this relationship after a successful Google Cloud Storage operation.

Reads Attributes:

None specified.

Writes Attributes:

filenameThe name of the file
gcs.bucketBucket of the object.
gcs.keyName of the object.
gcs.sizeSize of the object.
gcs.cache.controlData cache control of the object.
gcs.component.countThe number of components which make up the object.
gcs.content.dispositionThe data content disposition of the object.
gcs.content.encodingThe content encoding of the object.
gcs.content.languageThe content language of the object.
mime.typeThe MIME/Content-Type of the object
gcs.crc32cThe CRC32C checksum of object's data, encoded in base64 in big-endian order.
gcs.create.timeThe creation time of the object (milliseconds)
gcs.update.timeThe last modification time of the object (milliseconds)
gcs.encryption.algorithmThe algorithm used to encrypt the object.
gcs.encryption.sha256The SHA256 hash of the key used to encrypt the object
gcs.etagThe HTTP 1.1 Entity tag for the object.
gcs.generated.idThe service-generated for the object
gcs.generationThe data generation of the object.
gcs.md5The MD5 hash of the object's data encoded in base64. media download link to the object.
gcs.metagenerationThe metageneration of the object.
gcs.ownerThe owner (uploader) of the object.
gcs.owner.typeThe ACL entity type of the uploader of the object.
gcs.uriThe URI of the object as a string.

State management:

CLUSTERAfter performing a listing of keys, the timestamp of the newest key is stored, along with the keys that share that same timestamp. This allows the Processor to list only keys 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.


This component is not restricted.

Input requirement:

This component does not allow an incoming relationship.

System Resource Considerations:

None specified.

See Also:

PutGCSObject, DeleteGCSObject, FetchGCSObject