airflow.providers.google.cloud.transfers.cassandra_to_gcs

This module contains operator for copying data from Cassandra to Google Cloud Storage in JSON format.

Module Contents

class airflow.providers.google.cloud.transfers.cassandra_to_gcs.CassandraToGCSOperator(*, cql: str, bucket: str, filename: str, schema_filename: Optional[str] = None, approx_max_file_size_bytes: int = 1900000000, gzip: bool = False, cassandra_conn_id: str = 'cassandra_default', gcp_conn_id: str = 'google_cloud_default', google_cloud_storage_conn_id: Optional[str] = None, delegate_to: Optional[str] = None, impersonation_chain: Optional[Union[str, Sequence[str]]] = None, **kwargs)[source]

Bases: airflow.models.BaseOperator

Copy data from Cassandra to Google Cloud Storage in JSON format

Note: Arrays of arrays are not supported.

Parameters

  • cql (str) – The CQL to execute on the Cassandra table.

  • bucket (str) – The bucket to upload to.

  • filename (str) – The filename to use as the object name when uploading to Google Cloud Storage. A {} should be specified in the filename to allow the operator to inject file numbers in cases where the file is split due to size.

  • schema_filename (str) – If set, the filename to use as the object name when uploading a .json file containing the BigQuery schema fields for the table that was dumped from MySQL.

  • approx_max_file_size_bytes (long) – This operator supports the ability to split large table dumps into multiple files (see notes in the filename param docs above). This param allows developers to specify the file size of the splits. Check https://cloud.google.com/storage/quotas to see the maximum allowed file size for a single object.

  • cassandra_conn_id (str) – Reference to a specific Cassandra hook.

  • gzip (bool) – Option to compress file for upload

  • gcp_conn_id (str) – (Optional) The connection ID used to connect to Google Cloud.

  • google_cloud_storage_conn_id (str) – (Deprecated) The connection ID used to connect to Google Cloud. This parameter has been deprecated. You should pass the gcp_conn_id parameter instead.

  • delegate_to (str) – The account to impersonate using domain-wide delegation of authority, if any. For this to work, the service account making the request must have domain-wide delegation enabled.

  • impersonation_chain (Union[str, Sequence[str]]) – Optional service account to impersonate using short-term credentials, or chained list of accounts required to get the access_token of the last account in the list, which will be impersonated in the request. If set as a string, the account must grant the originating account the Service Account Token Creator IAM role. If set as a sequence, the identities from the list must grant Service Account Token Creator IAM role to the directly preceding identity, with first account from the list granting this role to the originating account (templated).

template_fields = ['cql', 'bucket', 'filename', 'schema_filename', 'impersonation_chain'][source]
template_ext = ['.cql'][source]
ui_color = #a0e08c[source]
CQL_TYPE_MAP[source]
execute(self, context: Dict[str, str])[source]
_write_local_data_files(self, cursor)[source]

Takes a cursor, and writes results to a local file.

Returns

A dictionary where keys are filenames to be used as object names in GCS, and values are file handles to local files that contain the data for the GCS objects.

_write_local_schema_file(self, cursor)[source]

Takes a cursor, and writes the BigQuery schema for the results to a local file system.

Returns

A dictionary where key is a filename to be used as an object name in GCS, and values are file handles to local files that contains the BigQuery schema fields in .json format.

_upload_to_gcs(self, files_to_upload: Dict[str, Any])[source]
classmethod generate_data_dict(cls, names: Iterable[str], values: Any)[source]

Generates data structure that will be stored as file in GCS.

classmethod convert_value(cls, value: Optional[Any])[source]

Convert value to BQ type.

classmethod convert_array_types(cls, value: Union[List[Any], SortedSet])[source]

Maps convert_value over array.

classmethod convert_user_type(cls, value: Any)[source]

Converts a user type to RECORD that contains n fields, where n is the number of attributes. Each element in the user type class will be converted to its corresponding data type in BQ.

classmethod convert_tuple_type(cls, values: Tuple[Any])[source]

Converts a tuple to RECORD that contains n fields, each will be converted to its corresponding data type in bq and will be named ‘field_<index>’, where index is determined by the order of the tuple elements defined in cassandra.

classmethod convert_map_type(cls, value: OrderedMapSerializedKey)[source]

Converts a map to a repeated RECORD that contains two fields: ‘key’ and ‘value’, each will be converted to its corresponding data type in BQ.

classmethod generate_schema_dict(cls, name: str, type_: Any)[source]

Generates BQ schema.

classmethod get_bq_fields(cls, type_: Any)[source]

Converts non simple type value to BQ representation.

static is_simple_type(type_: Any)[source]

Check if type is a simple type.

static is_array_type(type_: Any)[source]

Check if type is an array type.

static is_record_type(type_: Any)[source]

Checks the record type.

classmethod get_bq_type(cls, type_: Any)[source]

Converts type to equivalent BQ type.

classmethod get_bq_mode(cls, type_: Any)[source]

Converts type to equivalent BQ mode.

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