[sensors] Make AutomationConditionSensorDefinition entity limit configurable via max_entities

[raghav-reglobe]

Summary & Motivation

User-code automation condition sensors (use_user_code_server=True) are capped at a hardcoded MAX_ENTITIES = 500 assets/checks. Deployments with large external-asset graphs (assets materialized by out-of-process writers, where custom AutomationCondition subclasses — which require the user-code-server path — drive scheduling) currently have to define dozens of sensors purely to satisfy the constant, even when a single selection is the natural unit.

This makes the limit configurable via an optional max_entities parameter (beta, requires use_user_code_server=True). The default behavior is unchanged (500), and the error message now points at the new parameter as one of the remediation options. The docstring already described the limit as what "currently" applies, suggesting it was intended to be tunable eventually.

Test Plan

Extended dagster_tests/definitions_tests/test_automation_condition_sensor_definition.py:

• parameter validation (positive int; rejected without use_user_code_server, mirroring default_condition)
• default behavior unchanged (500) and value survives with_attributes copies
• against a 600-asset graph: default raises, max_entities=1000 evaluates, max_entities=100 raises with the lowered limit

All 8 tests in the file pass locally.

Changelog

AutomationConditionSensorDefinition now accepts an optional max_entities parameter (beta), allowing the default 500 assets-or-checks limit for user-code-server sensors to be adjusted.

🤖 Generated with Claude Code

[greptile-apps]

Greptile Summary

This PR makes the hard-coded MAX_ENTITIES = 500 limit on AutomationConditionSensorDefinition configurable via an optional beta max_entities parameter, restricted to use_user_code_server=True sensors. Default behavior is fully preserved.

• Adds max_entities: int | None = None to __init__, dagster_internal_init (no default, matching the IHasInternalInit contract), and with_attributes; a property coalesces None to MAX_ENTITIES (500) at call time.
• Validation rejects non-positive values and disallows the parameter when use_user_code_server=False, mirroring the existing default_condition guard; the error message now lists max_entities as a remediation option.

Confidence Score: 5/5

Safe to merge; the change is additive, the default limit of 500 is fully preserved, and all validation paths are covered by tests.

The change is additive: new parameter, new validation, property that defaults to the existing constant. The IHasInternalInit contract is correctly satisfied (no default in dagster_internal_init), with_attributes propagates the raw stored value, and the runtime guard in _evaluate now reads from the property. Tests cover the full matrix of valid/invalid inputs and runtime behavior at both the default and custom limits.

No files require special attention.

Important Files Changed

Filename	Overview
python_modules/dagster/dagster/_core/definitions/automation_condition_sensor_definition.py	Adds optional max_entities beta parameter; validation, property accessor, dagster_internal_init, and with_attributes are all updated consistently.
python_modules/dagster/dagster_tests/definitions_tests/test_automation_condition_sensor_definition.py	New tests cover parameter validation, default/override behavior, with_attributes round-trip, and a 600-asset graph to exercise the limit at runtime.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[AutomationConditionSensorDefinition.__init__] --> B{max_entities provided?}
    B -- Yes --> C{max_entities > 0?}
    B -- No --> D[_max_entities = None]
    C -- No --> E[raise ParameterCheckError
'must be positive integer']
    C -- Yes --> F{use_user_code_server=True?}
    F -- No --> G[raise ParameterCheckError
'not supported for non-user-code sensor']
    F -- Yes --> H[_max_entities = max_entities]
    D --> I[max_entities property
returns MAX_ENTITIES 500]
    H --> J[max_entities property
returns _max_entities]
    K[_evaluate called] --> L[Build AutomationTickEvaluationContext]
    L --> M{total_keys > sensor_def.max_entities?}
    M -- Yes --> N[raise DagsterInvalidInvocationError]
    M -- No --> O[evaluation_context.evaluate
return SensorResult]

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flowchart TD
    A[AutomationConditionSensorDefinition.__init__] --> B{max_entities provided?}
    B -- Yes --> C{max_entities > 0?}
    B -- No --> D[_max_entities = None]
    C -- No --> E[raise ParameterCheckError
'must be positive integer']
    C -- Yes --> F{use_user_code_server=True?}
    F -- No --> G[raise ParameterCheckError
'not supported for non-user-code sensor']
    F -- Yes --> H[_max_entities = max_entities]
    D --> I[max_entities property
returns MAX_ENTITIES 500]
    H --> J[max_entities property
returns _max_entities]
    K[_evaluate called] --> L[Build AutomationTickEvaluationContext]
    L --> M{total_keys > sensor_def.max_entities?}
    M -- Yes --> N[raise DagsterInvalidInvocationError]
    M -- No --> O[evaluation_context.evaluate
return SensorResult]

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_{Reviews (2): Last reviewed commit: "[sensors] make AutomationConditionSensor..." | Re-trigger Greptile}

[greptile-apps]

Remove the = None default to satisfy the IHasInternalInit contract. The only caller (with_attributes) already passes this kwarg explicitly, so no callers break.

Suggested change

	default_condition: AutomationCondition | None,
	max_entities: int | None = None,
	) -> "AutomationConditionSensorDefinition":
	default_condition: AutomationCondition | None,
	max_entities: int | None,
	) -> "AutomationConditionSensorDefinition":

Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!