Deltalake + Pandas (dagster-deltalake-pandas)¶

This library provides an integration with the Delta Lake storage framework.

Related guides:

• Using Dagster with Delta Lake guide

• DeltaLake I/O manager reference

dagster_deltalake_pandas.DeltaLakePandasIOManager IOManagerDefinition[source]¶

Config Schema:

root_uri (dagster.StringSource):

Storage location where Delta tables are stored.

mode (Union[WriteMode, None], optional):

The write mode passed to save the output.

Default Value: ‘overwrite’

overwrite_schema (Union[dagster.BoolSource, None], optional):

Default Value: False

writer_engine (Union[WriterEngine, None], optional):

Engine passed to write_deltalake.

Default Value: ‘pyarrow’

storage_options (selector):

Config Schema:

azure (strict dict):

Storage configuration for Microsoft Azure Blob or ADLS Gen 2 object store.

Config Schema:

account_name (dagster.StringSource):

client_id (Union[dagster.StringSource, None], optional):

client_secret (Union[dagster.StringSource, None], optional):

tenant_id (Union[dagster.StringSource, None], optional):

federated_token_file (Union[dagster.StringSource, None], optional):

account_key (Union[dagster.StringSource, None], optional):

sas_key (Union[dagster.StringSource, None], optional):

token (Union[dagster.StringSource, None], optional):

use_azure_cli (Union[dagster.BoolSource, None], optional):

use_fabric_endpoint (Union[dagster.BoolSource, None], optional):

msi_resource_id (Union[dagster.StringSource, None], optional):

msi_endpoint (Union[dagster.StringSource, None], optional):

container_name (Union[dagster.StringSource, None], optional):

s3 (strict dict, optional):

Storage configuration for Amazon Web Services (AWS) S3 object store.

Default Value:

{
    "imdsv1_fallback": false
}

Config Schema:

access_key_id (Union[dagster.StringSource, None], optional):

secret_access_key (Union[dagster.StringSource, None], optional):

region (Union[dagster.StringSource, None], optional):

bucket (Union[dagster.StringSource, None], optional):

endpoint (Union[dagster.StringSource, None], optional):

token (Union[dagster.StringSource, None], optional):

imdsv1_fallback (Union[dagster.BoolSource, None], optional):

Default Value: False

virtual_hosted_style_request (Union[dagster.StringSource, None], optional):

unsigned_payload (Union[dagster.BoolSource, None], optional):

checksum (Union[dagster.StringSource, None], optional):

metadata_endpoint (Union[dagster.StringSource, None], optional):

container_credentials_relative_uri (Union[dagster.StringSource, None], optional):

copy_if_not_exists (Union[dagster.StringSource, None], optional):

allow_unsafe_rename (Union[dagster.BoolSource, None], optional):

local (strict dict, optional):

Storage configuration for local object store.

Default Value:

{}

gcs (strict dict, optional):

Storage configuration for Google Cloud Storage object store.

Default Value:

{}

Config Schema:

service_account (Union[dagster.StringSource, None], optional):

service_account_key (Union[dagster.StringSource, None], optional):

bucket (Union[dagster.StringSource, None], optional):

application_credentials (Union[dagster.StringSource, None], optional):

client_options (Union[strict dict, None], optional):

Additional configuration passed to http client.

table_config (Union[dict, None], optional):

Additional config and metadata added to table on creation.

schema (Union[dagster.StringSource, None], optional):

Name of the schema to use.

custom_metadata (Union[dict, None], optional):

Custom metadata that is added to transaction commit.

writer_properties (Union[dict, None], optional):

Writer properties passed to the rust engine writer.

Base class for an IO manager definition that reads inputs from and writes outputs to Delta Lake.

Examples

from dagster_deltalake import DeltaLakeIOManager
from dagster_deltalake_pandas import DeltaLakePandasTypeHandler

class MyDeltaLakeIOManager(DeltaLakeIOManager):
    @staticmethod
    def type_handlers() -> Sequence[DbTypeHandler]:
        return [DeltaLakePandasTypeHandler()]

@asset(
    key_prefix=["my_schema"]  # will be used as the schema (parent folder) in Delta Lake
)
def my_table() -> pd.DataFrame:  # the name of the asset will be the table name
    ...

defs = Definitions(
    assets=[my_table],
    resources={"io_manager": MyDeltaLakeIOManager()}
)

If you do not provide a schema, Dagster will determine a schema based on the assets and ops using the I/O Manager. For assets, the schema will be determined from the asset key, as in the above example. For ops, the schema can be specified by including a “schema” entry in output metadata. If none of these is provided, the schema will default to “public”.

@op(
    out={"my_table": Out(metadata={"schema": "my_schema"})}
)
def make_my_table() -> pd.DataFrame:
    ...

To only use specific columns of a table as input to a downstream op or asset, add the metadata “columns” to the In or AssetIn.

@asset(
    ins={"my_table": AssetIn("my_table", metadata={"columns": ["a"]})}
)
def my_table_a(my_table: pd.DataFrame):
    # my_table will just contain the data from column "a"
    ...

class dagster_deltalake_pandas.DeltaLakePandasTypeHandler[source]¶