DagsterInvalidDefinitionError: "context" is not a valid name in Dagster. It conflicts with a Dagster or python reserved keyword

[valerio-bud]

In dagster (my current version is 1.7.10) I am getting this error when I define an asset that has both an input from another asset and wants to use the asset execution context:

dagster._core.errors.DagsterInvalidDefinitionError: "context" is not a valid name in Dagster. It conflicts with a Dagster or python reserved keyword.

This is the code:

from dagster import asset, AssetIn, AssetExecutionContext, Definitions


@asset
def parent_asset(context: AssetExecutionContext) -> None:
    return 'hi there!'


@asset(ins={'parent_asset': AssetIn('parent_asset')})
def my_asset(
    parent_asset: str,
    context: AssetExecutionContext,
) -> None:
    print(parent_asset + ' whatever')


Definitions(assets=[parent_asset, my_asset])

Note that: if I remove the context argument from my_asset arguments. Then the code works, but it's weird because parent_asset DID have the context argument but did not raise error. So the error is raised specifically when I am using ins in the asset definitions and the context at the same time.

The full stack trace:

Traceback (most recent call last):
  File ".scratches/context_example.py", line 10, in <module>
    def my_asset(
  File "env/lib/python3.10/site-packages/dagster/_core/definitions/decorators/asset_decorator.py", line 264, in inner
    return create_assets_def_from_fn_and_decorator_args(args, fn)
  File "env/lib/python3.10/site-packages/dagster/_core/definitions/decorators/asset_decorator.py", line 454, in create_assets_def_from_fn_and_decorator_args
    return builder.create_assets_definition()
  File "env/lib/python3.10/site-packages/dagster/_core/definitions/decorators/decorator_assets_definition_builder.py", line 519, in create_assets_definition
    node_def=self._create_op_definition(),
  File "env/lib/python3.10/site-packages/dagster/_core/definitions/decorators/decorator_assets_definition_builder.py", line 495, in _create_op_definition
    return _Op(
  File "env/lib/python3.10/site-packages/dagster/_core/definitions/decorators/op_decorator.py", line 125, in __call__
    op_def = OpDefinition.dagster_internal_init(
  File "env/lib/python3.10/site-packages/dagster/_core/definitions/op_definition.py", line 207, in dagster_internal_init
    return OpDefinition(
  File "env/lib/python3.10/site-packages/dagster/_core/decorator_utils.py", line 203, in wrapped_with_pre_call_fn
    return fn(*args, **kwargs)
  File "env/lib/python3.10/site-packages/dagster/_core/definitions/op_definition.py", line 140, in __init__
    input_defs = [
  File "env/lib/python3.10/site-packages/dagster/_core/definitions/op_definition.py", line 141, in <listcomp>
    inp.to_definition(name) for name, inp in sorted(ins.items(), key=lambda inp: inp[0])
  File "env/lib/python3.10/site-packages/dagster/_core/definitions/input.py", line 504, in to_definition
    return InputDefinition(
  File "env/lib/python3.10/site-packages/dagster/_core/decorator_utils.py", line 203, in wrapped_with_pre_call_fn
    return fn(*args, **kwargs)
  File "env/lib/python3.10/site-packages/dagster/_core/decorator_utils.py", line 203, in wrapped_with_pre_call_fn
    return fn(*args, **kwargs)
  File "env/lib/python3.10/site-packages/dagster/_core/definitions/input.py", line 114, in __init__
    self._name = check_valid_name(name, allow_list=["config"])
  File "env/lib/python3.10/site-packages/dagster/_core/definitions/utils.py", line 81, in check_valid_name
    raise DagsterInvalidDefinitionError(
dagster._core.errors.DagsterInvalidDefinitionError: "context" is not a valid name in Dagster. It conflicts with a Dagster or python reserved keyword.

[cmpadden]

Hi @valerio-bud - this appears to be due to the order of the arguments. I confirmed that moving the context argument before the parent_asset argument in my_asset resolves the issue.

from dagster import asset, AssetIn, AssetExecutionContext, Definitions


@asset
def parent_asset(context: AssetExecutionContext) -> None:
    return 'hi there!'


@asset(ins={'parent_asset': AssetIn('parent_asset')})
def my_asset(
    context: AssetExecutionContext,
    parent_asset: str,
) -> None:
    print(parent_asset + ' whatever')


Definitions(assets=[parent_asset, my_asset])