ListGCSBucket
Description
Retrieves a listing of objects from a 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.
Tags
gcs, google, google cloud, list, storage
Properties
In the list below required Properties are shown with an asterisk (*). Other properties 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 |
|---|---|---|---|---|
| GCP Credentials Provider Service * | GCP Credentials Provider Service | Controller Service: GCPCredentialsService Implementations: GCPCredentialsControllerService | The Controller Service used to obtain Google Cloud Platform credentials. | |
| Project ID | gcp-project-id | Google Cloud Project ID Supports Expression Language, using Environment variables. | ||
| Bucket * | gcs-bucket | Bucket of the object. Supports Expression Language, using Environment variables. | ||
| Prefix | gcs-prefix | The prefix used to filter the object list. In most cases, it should end with a forward slash ('/'). Supports Expression Language, using Environment variables. | ||
| Listing Strategy * | listing-strategy | Tracking Timestamps |
| Specify how to determine new/updated entities. See each strategy descriptions for detail. |
| Entity Tracking State Cache * | et-state-cache | Controller Service: DistributedMapCacheClient Implementations: HazelcastMapCacheClient MapCacheClientService RedisDistributedMapCacheClientService SimpleRedisDistributedMapCacheClientService | 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:
| |
| Entity Tracking Initial Listing Target | et-initial-listing-target | All Available |
| Specify how initial listing should be handled. Used by 'Tracking Entities' strategy. This property is only considered if:
|
| Entity Tracking Time Window * | et-time-window | 3 hours | Specify 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, using Environment variables. This property is only considered if:
| |
| Record Writer | record-writer | Controller Service: RecordSetWriterFactory Implementations: AvroRecordSetWriter CSVRecordSetWriter FreeFormTextRecordSetWriter JsonRecordSetWriter RecordSetWriterLookup ScriptedRecordSetWriter XMLRecordSetWriter | 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. | |
| Use Generations * | gcs-use-generations | false |
| Specifies whether to use GCS Generations, if applicable. If false, only the latest version of each object will be returned. |
| Number of retries * | gcp-retry-count | 6 | How many retry attempts should be made before routing to the failure relationship. | |
| Storage API URL | storage-api-url | Overrides the default storage URL. Configuring an alternative Storage API URL also overrides the HTTP Host header on requests as described in the Google documentation for Private Service Connections. Supports Expression Language, using Environment variables. | ||
| Proxy Configuration Service | proxy-configuration-service | Controller Service: ProxyConfigurationService Implementations: StandardProxyConfigurationService | Specifies the Proxy Configuration Controller Service to proxy network requests. Supported proxies: HTTP + AuthN |
Dynamic Properties
This component does not support dynamic properties.
Relationships
| Name | Description |
|---|---|
| success | FlowFiles are routed to this relationship after a successful Google Cloud Storage operation. |
Reads Attributes
This processor does not read attributes.
Writes Attributes
| Name | Description |
|---|---|
| filename | The name of the file |
| gcs.bucket | Bucket of the object. |
| gcs.cache.control | Data cache control of the object. |
| gcs.component.count | The number of components which make up the object. |
| gcs.content.disposition | The data content disposition of the object. |
| gcs.content.encoding | The content encoding of the object. |
| gcs.content.language | The content language of the object. |
| gcs.crc32c | The CRC32C checksum of object's data, encoded in base64 in big-endian order. |
| gcs.create.time | The creation time of the object (milliseconds) |
| gcs.encryption.algorithm | The algorithm used to encrypt the object. |
| gcs.encryption.sha256 | The SHA256 hash of the key used to encrypt the object |
| gcs.etag | The HTTP 1.1 Entity tag for the object. |
| gcs.generated.id | The service-generated for the object |
| gcs.generation | The data generation of the object. |
| gcs.key | Name of the object. |
| gcs.md5 | The MD5 hash of the object's data encoded in base64. |
| gcs.media.link | The media download link to the object. |
| gcs.metageneration | The metageneration of the object. |
| gcs.owner | The owner (uploader) of the object. |
| gcs.owner.type | The ACL entity type of the uploader of the object. |
| gcs.size | Size of the object. |
| gcs.update.time | The last modification time of the object (milliseconds) |
| gcs.uri | The URI of the object as a string. |
| mime.type | The MIME/Content-Type of the object |
State Management
| Scope | Description |
|---|---|
| CLUSTER | After 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. |
Restricted
This component is not restricted.
Input Requirement
This component does not allow an incoming relationship.
System Resource Considerations
This component does not specify system resource considerations.