Datasets¶
Custom dataset implementations for Kedro-Dagster integration.
DagsterNothingDataset¶
kedro_dagster.datasets.DagsterNothingDataset
¶
Bases: AbstractDataset
A Kedro dataset used to represent placeholder outputs.
This dataset can be used in Kedro pipelines to signify that a node has completed its task without actually producing any tangible output. It is particularly useful for enforcing execution order in pipelines where certain nodes need to run after others without passing data.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
metadata
|
dict[str, Any] or None
|
Optional metadata stored alongside the dataset. |
None
|
Examples:
>>> from kedro_dagster.datasets.nothing_dataset import DagsterNothingDataset
>>> nothing_ds = DagsterNothingDataset(metadata={"info": "no output"})
>>> data = nothing_ds.load()
>>> print(data)
__nothing__
>>> nothing_ds.save(data)
See Also
kedro_dagster.utils.is_nothing_asset_name :
Predicate that checks whether a catalog entry is this type.
Source code in src/kedro_dagster/datasets/nothing_dataset.py
DagsterPartitionedDataset¶
kedro_dagster.datasets.DagsterPartitionedDataset
¶
Bases: PartitionedDataset
Kedro dataset that enables Dagster partitioning.
This dataset wraps Kedro's PartitionedDataset to expose Dagster partition
definitions and mappings. It validates partition types at instantiation and
only supports a limited subset of Dagster's partition features.
Supported Partition Types:
- StaticPartitionsDefinition: Fixed list of partition keys
Supported Partition Mappings:
- StaticPartitionMapping: Explicit upstream→downstream key mapping
- IdentityPartitionMapping: 1:1 mapping with matching keys
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
path
|
str
|
Base path for partitions. |
required |
dataset
|
dict[str, Any]
|
Underlying dataset config. |
required |
partition
|
dict[str, Any]
|
Partition definition config or type. |
required |
partition_mapping
|
dict[str, Any] or None
|
Optional downstream partition mappings. |
None
|
filepath_arg
|
str
|
Arg name in underlying dataset to pass the resolved path. |
'filepath'
|
filename_suffix
|
str
|
Optional suffix appended to partitioned filename. |
''
|
credentials
|
dict[str, Any] or None
|
Credentials for the underlying dataset. |
None
|
load_args
|
dict[str, Any] or None
|
Load args for the underlying dataset. |
None
|
fs_args
|
dict[str, Any] or None
|
Filesystem args for the underlying dataset. |
None
|
overwrite
|
bool
|
Whether to overwrite on save. |
False
|
save_lazily
|
bool
|
Whether to save lazily. |
True
|
metadata
|
dict[str, Any] or None
|
Arbitrary metadata. |
None
|
Examples:
Basic usage with StaticPartitionsDefinition:
my_partitioned_dataset:
type: kedro_dagster.DagsterPartitionedDataset
path: data/partitions/
dataset:
type: pandas.CSVDataset
partition:
type: dagster.StaticPartitionsDefinition
partition_keys: ["A", "B", "C"]
With StaticPartitionMapping:
upstream:
type: kedro_dagster.DagsterPartitionedDataset
path: data/01_raw/upstream/
dataset:
type: pandas.CSVDataset
partition:
type: dagster.StaticPartitionsDefinition
partition_keys: ["1.csv", "2.csv"]
partition_mappings:
downstream:
type: dagster.StaticPartitionMapping
downstream_partition_keys_by_upstream_partition_key:
1.csv: 10.csv
2.csv: 20.csv
With IdentityPartitionMapping:
upstream:
type: kedro_dagster.DagsterPartitionedDataset
path: data/02_raw/upstream/
dataset:
type: pickle.PickleDataset
partition:
type: dagster.StaticPartitionsDefinition
partition_keys: ["2024-01.pkl", "2024-02.pkl"]
partition_mappings:
downstream:
type: dagster.IdentityPartitionMapping
See Also
kedro_dagster.datasets.nothing_dataset.DagsterNothingDataset :
Companion sentinel dataset for Nothing-typed assets.
kedro_dagster.catalog.CatalogTranslator :
Translates these datasets into Dagster IO managers.
Source code in src/kedro_dagster/datasets/partitioned_dataset.py
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load()
¶
Load partitioned data lazily as callables per partition key.
Returns:
| Type | Description |
|---|---|
dict[str, Callable[[], Any]]
|
Map of partition key to loader callable. |
Source code in src/kedro_dagster/datasets/partitioned_dataset.py
save(data)
¶
Save partitioned data.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
data
|
dict[str, Any]
|
Map of partition key to data. |
required |
Source code in src/kedro_dagster/datasets/partitioned_dataset.py
__repr__()
¶
Return a human-friendly representation of the dataset.