Assignment Action: Architecture Reference#

Purpose#

The Assignment action implements the “Mutation” logic of FlexiRule. It is designed to handle sequential state updates to both the triggering document (doc) and the execution context (vars). It integrates directly with the Value Resolver and Normalization Pipeline.

Class Structure#

AssignmentHandler(ActionHandler)#

• Responsibility: Processes a grid of assignment rows.
• Key Method: execute(action, context, engine)

Sequential Mutation Engine#

Unlike standard field mapping, assignments are processed sequentially (top-to-bottom) within a single node.

1. Row Isolation: Each row in the configuration grid is treated as an independent mutation event.
2. Conditional Evaluation: The when condition of the row is evaluated against the current context (which may have been modified by previous rows in the same block).
3. Value Resolution: The value is resolved using the unified ValueResolver.
4. Pipeline Application: If a normalization pipeline or profile is configured, it is applied to the resolved value.
5. Mutation: The final value is written to the target path (doc.field or vars.var).

Integration with Normalization#

The AssignmentHandler uses the NormalizationService to apply transformations.

• Standard Operations: trim, lowercase, slug, etc.
• Profiles: Pre-configured sets of operations stored in the database.
• Implementation: See flexirule/ruleflow/utils/normalization.py.

Path Resolvers#

The handler supports deep path resolution for targets:

• doc.base_amount: Standard field.
• vars.results.0.name: Deeply nested variable (using dot/index notation).

Source Files#

• Backend: flexirule/ruleflow/core/action_handlers/assignment.py
• Normalization: flexirule/ruleflow/utils/normalization.py
• Value Resolver: flexirule/ruleflow/core/value_resolver.py