Class BigQueryReadClient (2.16.2)

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BigQueryReadClient(*, credentials: Optional[google.auth.credentials.Credentials] = None, transport: Optional[Union[str, google.cloud.bigquery_storage_v1beta2.services.big_query_read.transports.base.BigQueryReadTransport]] = None, client_options: Optional[google.api_core.client_options.ClientOptions] = None, client_info: google.api_core.gapic_v1.client_info.ClientInfo = <google.api_core.gapic_v1.client_info.ClientInfo object>)

Client for interacting with BigQuery Storage API.

The BigQuery storage API can be used to read data stored in BigQuery.

Inheritance

builtins.object > google.cloud.bigquery_storage_v1beta2.services.big_query_read.client.BigQueryReadClient > BigQueryReadClient

Properties

transport

Returns the transport used by the client instance.

Returns
TypeDescription
BigQueryReadTransportThe transport used by the client instance.

Methods

BigQueryReadClient

BigQueryReadClient(*, credentials: Optional[google.auth.credentials.Credentials] = None, transport: Optional[Union[str, google.cloud.bigquery_storage_v1beta2.services.big_query_read.transports.base.BigQueryReadTransport]] = None, client_options: Optional[google.api_core.client_options.ClientOptions] = None, client_info: google.api_core.gapic_v1.client_info.ClientInfo = <google.api_core.gapic_v1.client_info.ClientInfo object>)

Instantiates the big query read client.

Parameters
NameDescription
credentials Optional[google.auth.credentials.Credentials]

The authorization credentials to attach to requests. These credentials identify the application to the service; if none are specified, the client will attempt to ascertain the credentials from the environment.

transport Union[str, BigQueryReadTransport]

The transport to use. If set to None, a transport is chosen automatically.

client_options google.api_core.client_options.ClientOptions

Custom options for the client. It won't take effect if a transport instance is provided. (1) The api_endpoint property can be used to override the default endpoint provided by the client. GOOGLE_API_USE_MTLS_ENDPOINT environment variable can also be used to override the endpoint: "always" (always use the default mTLS endpoint), "never" (always use the default regular endpoint) and "auto" (auto switch to the default mTLS endpoint if client certificate is present, this is the default value). However, the api_endpoint property takes precedence if provided. (2) If GOOGLE_API_USE_CLIENT_CERTIFICATE environment variable is "true", then the client_cert_source property can be used to provide client certificate for mutual TLS transport. If not provided, the default SSL client certificate will be used if present. If GOOGLE_API_USE_CLIENT_CERTIFICATE is "false" or not set, no client certificate will be used.

client_info google.api_core.gapic_v1.client_info.ClientInfo

The client info used to send a user-agent string along with API requests. If None, then default info will be used. Generally, you only need to set this if you're developing your own client library.

Exceptions
TypeDescription
google.auth.exceptions.MutualTLSChannelErrorIf mutual TLS transport creation failed for any reason.

__exit__

__exit__(type, value, traceback)

Releases underlying transport's resources.

common_billing_account_path

common_billing_account_path(billing_account: str)

Returns a fully-qualified billing_account string.

common_folder_path

common_folder_path(folder: str)

Returns a fully-qualified folder string.

common_location_path

common_location_path(project: str, location: str)

Returns a fully-qualified location string.

common_organization_path

common_organization_path(organization: str)

Returns a fully-qualified organization string.

common_project_path

common_project_path(project: str)

Returns a fully-qualified project string.

create_read_session

create_read_session(request: Optional[Union[google.cloud.bigquery_storage_v1beta2.types.storage.CreateReadSessionRequest, dict]] = None, *, parent: Optional[str] = None, read_session: Optional[google.cloud.bigquery_storage_v1beta2.types.stream.ReadSession] = None, max_stream_count: Optional[int] = None, retry: Union[google.api_core.retry.Retry, google.api_core.gapic_v1.method._MethodDefault] = <_MethodDefault._DEFAULT_VALUE: <object object>>, timeout: Optional[float] = None, metadata: Sequence[Tuple[str, str]] = ())

Creates a new read session. A read session divides the contents of a BigQuery table into one or more streams, which can then be used to read data from the table. The read session also specifies properties of the data to be read, such as a list of columns or a push-down filter describing the rows to be returned.

A particular row can be read by at most one stream. When the caller has reached the end of each stream in the session, then all the data in the table has been read.

Data is assigned to each stream such that roughly the same number of rows can be read from each stream. Because the server-side unit for assigning data is collections of rows, the API does not guarantee that each stream will return the same number or rows. Additionally, the limits are enforced based on the number of pre-filtered rows, so some filters can lead to lopsided assignments.

Read sessions automatically expire 6 hours after they are created and do not require manual clean-up by the caller.

# This snippet has been automatically generated and should be regarded as a
# code template only.
# It will require modifications to work:
# - It may require correct/in-range values for request initialization.
# - It may require specifying regional endpoints when creating the service
#   client as shown in:
#   https://googleapis.dev/python/google-api-core/latest/client_options.html
from google.cloud import bigquery_storage_v1beta2

def sample_create_read_session():
    # Create a client
    client = bigquery_storage_v1beta2.BigQueryReadClient()

    # Initialize request argument(s)
    request = bigquery_storage_v1beta2.CreateReadSessionRequest(
        parent="parent_value",
    )

    # Make the request
    response = client.create_read_session(request=request)

    # Handle the response
    print(response)
Parameters
NameDescription
request Union[google.cloud.bigquery_storage_v1beta2.types.CreateReadSessionRequest, dict]

The request object. Request message for CreateReadSession.

parent str

Required. The request project that owns the session, in the form of projects/{project_id}. This corresponds to the parent field on the request instance; if request is provided, this should not be set.

read_session google.cloud.bigquery_storage_v1beta2.types.ReadSession

Required. Session to be created. This corresponds to the read_session field on the request instance; if request is provided, this should not be set.

max_stream_count int

Max initial number of streams. If unset or zero, the server will provide a value of streams so as to produce reasonable throughput. Must be non-negative. The number of streams may be lower than the requested number, depending on the amount parallelism that is reasonable for the table. Error will be returned if the max count is greater than the current system max limit of 1,000. Streams must be read starting from offset 0. This corresponds to the max_stream_count field on the request instance; if request is provided, this should not be set.

retry google.api_core.retry.Retry

Designation of what errors, if any, should be retried.

timeout float

The timeout for this request.

metadata Sequence[Tuple[str, str]]

Strings which should be sent along with the request as metadata.

Returns
TypeDescription
google.cloud.bigquery_storage_v1beta2.types.ReadSessionInformation about the ReadSession.

from_service_account_file

from_service_account_file(filename: str, *args, **kwargs)

Creates an instance of this client using the provided credentials file.

Parameter
NameDescription
filename str

The path to the service account private key json file.

Returns
TypeDescription
BigQueryReadClientThe constructed client.

from_service_account_info

from_service_account_info(info: dict, *args, **kwargs)

Creates an instance of this client using the provided credentials info.

Parameter
NameDescription
info dict

The service account private key info.

Returns
TypeDescription
BigQueryReadClientThe constructed client.

from_service_account_json

from_service_account_json(filename: str, *args, **kwargs)

Creates an instance of this client using the provided credentials file.

Parameter
NameDescription
filename str

The path to the service account private key json file.

Returns
TypeDescription
BigQueryReadClientThe constructed client.

get_mtls_endpoint_and_cert_source

get_mtls_endpoint_and_cert_source(
    client_options: Optional[google.api_core.client_options.ClientOptions] = None,
)

Return the API endpoint and client cert source for mutual TLS.

The client cert source is determined in the following order: (1) if GOOGLE_API_USE_CLIENT_CERTIFICATE environment variable is not "true", the client cert source is None. (2) if client_options.client_cert_source is provided, use the provided one; if the default client cert source exists, use the default one; otherwise the client cert source is None.

The API endpoint is determined in the following order: (1) if client_options.api_endpoint if provided, use the provided one. (2) if GOOGLE_API_USE_CLIENT_CERTIFICATE environment variable is "always", use the default mTLS endpoint; if the environment variabel is "never", use the default API endpoint; otherwise if client cert source exists, use the default mTLS endpoint, otherwise use the default API endpoint.

More details can be found at https://google.aip.dev/auth/4114.

Parameter
NameDescription
client_options google.api_core.client_options.ClientOptions

Custom options for the client. Only the api_endpoint and client_cert_source properties may be used in this method.

Exceptions
TypeDescription
google.auth.exceptions.MutualTLSChannelErrorIf any errors happen.
Returns
TypeDescription
Tuple[str, Callable[[], Tuple[bytes, bytes]]]returns the API endpoint and the client cert source to use.

parse_common_billing_account_path

parse_common_billing_account_path(path: str)

Parse a billing_account path into its component segments.

parse_common_folder_path

parse_common_folder_path(path: str)

Parse a folder path into its component segments.

parse_common_location_path

parse_common_location_path(path: str)

Parse a location path into its component segments.

parse_common_organization_path

parse_common_organization_path(path: str)

Parse a organization path into its component segments.

parse_common_project_path

parse_common_project_path(path: str)

Parse a project path into its component segments.

parse_read_session_path

parse_read_session_path(path: str)

Parses a read_session path into its component segments.

parse_read_stream_path

parse_read_stream_path(path: str)

Parses a read_stream path into its component segments.

parse_table_path

parse_table_path(path: str)

Parses a table path into its component segments.

read_rows

read_rows(name, offset=0, retry=<_MethodDefault._DEFAULT_VALUE: <object object>>, timeout=<_MethodDefault._DEFAULT_VALUE: <object object>>, metadata=(), retry_delay_callback=None)

Reads rows from the table in the format prescribed by the read session. Each response contains one or more table rows, up to a maximum of 10 MiB per response; read requests which attempt to read individual rows larger than this will fail.

Each request also returns a set of stream statistics reflecting the estimated total number of rows in the read stream. This number is computed based on the total table size and the number of active streams in the read session, and may change as other streams continue to read data.

.. rubric:: Example

from google.cloud import bigquery_storage

client = bigquery_storage.BigQueryReadClient()

TODO: Initialize table:

table = "projects/{}/datasets/{}/tables/{}".format( ... 'project_id': 'your-data-project-id', ... 'dataset_id': 'your_dataset_id', ... 'table_id': 'your_table_id', ... )

TODO: Initialize parent:

parent = 'projects/your-billing-project-id'

requested_session = bigquery_storage.types.ReadSession( ... table=table, ... data_format=bigquery_storage.types.DataFormat.AVRO, ... ) session = client.create_read_session( ... parent=parent, read_session=requested_session ... )

stream = session.streams[0], # TODO: Also read any other streams. read_rows_stream = client.read_rows(stream.name)

for element in read_rows_stream.rows(session): ... # process element ... pass

Parameters
NameDescription
name str

Required. Name of the stream to start reading from, of the form projects/{project_id}/locations/{location}/sessions/{session_id}/streams/{stream_id}

offset Optional[int]

The starting offset from which to begin reading rows from in the stream. The offset requested must be less than the last row read from ReadRows. Requesting a larger offset is undefined.

retry Optional[google.api_core.retry.Retry]

A retry object used to retry requests. If None is specified, requests will not be retried.

timeout Optional[float]

The amount of time, in seconds, to wait for the request to complete. Note that if retry is specified, the timeout applies to each individual attempt.

metadata Optional[Sequence[Tuple[str, str]]]

Additional metadata that is provided to the method.

retry_delay_callback Optional[Callable[[float], None]]

If the client receives a retryable error that asks the client to delay its next attempt and retry_delay_callback is not None, BigQueryReadClient will call retry_delay_callback with the delay duration (in seconds) before it starts sleeping until the next attempt.

Exceptions
TypeDescription
google.api_core.exceptions.GoogleAPICallErrorIf the request failed for any reason.
google.api_core.exceptions.RetryErrorIf the request failed due to a retryable error and retry attempts failed.
ValueErrorIf the parameters are invalid.
Returns
TypeDescription
ReadRowsStreamAn iterable of ReadRowsResponse.

read_session_path

read_session_path(project: str, location: str, session: str)

Returns a fully-qualified read_session string.

read_stream_path

read_stream_path(project: str, location: str, session: str, stream: str)

Returns a fully-qualified read_stream string.

split_read_stream

split_read_stream(request: Optional[Union[google.cloud.bigquery_storage_v1beta2.types.storage.SplitReadStreamRequest, dict]] = None, *, retry: Union[google.api_core.retry.Retry, google.api_core.gapic_v1.method._MethodDefault] = <_MethodDefault._DEFAULT_VALUE: <object object>>, timeout: Optional[float] = None, metadata: Sequence[Tuple[str, str]] = ())

Splits a given ReadStream into two ReadStream objects. These ReadStream objects are referred to as the primary and the residual streams of the split. The original ReadStream can still be read from in the same manner as before. Both of the returned ReadStream objects can also be read from, and the rows returned by both child streams will be the same as the rows read from the original stream.

Moreover, the two child streams will be allocated back-to-back in the original ReadStream. Concretely, it is guaranteed that for streams original, primary, and residual, that original[0-j] = primary[0-j] and original[j-n] = residual[0-m] once the streams have been read to completion.

# This snippet has been automatically generated and should be regarded as a
# code template only.
# It will require modifications to work:
# - It may require correct/in-range values for request initialization.
# - It may require specifying regional endpoints when creating the service
#   client as shown in:
#   https://googleapis.dev/python/google-api-core/latest/client_options.html
from google.cloud import bigquery_storage_v1beta2

def sample_split_read_stream():
    # Create a client
    client = bigquery_storage_v1beta2.BigQueryReadClient()

    # Initialize request argument(s)
    request = bigquery_storage_v1beta2.SplitReadStreamRequest(
        name="name_value",
    )

    # Make the request
    response = client.split_read_stream(request=request)

    # Handle the response
    print(response)
Parameters
NameDescription
request Union[google.cloud.bigquery_storage_v1beta2.types.SplitReadStreamRequest, dict]

The request object. Request message for SplitReadStream.

retry google.api_core.retry.Retry

Designation of what errors, if any, should be retried.

timeout float

The timeout for this request.

metadata Sequence[Tuple[str, str]]

Strings which should be sent along with the request as metadata.

table_path

table_path(project: str, dataset: str, table: str)

Returns a fully-qualified table string.