Pipeline Service
================

Central orchestrator for Haystack pipeline management and execution.

The ``PipelineService`` provides:

* **Pipeline CRUD** - Create, read, update, delete pipeline definitions
* **Validation** - Validates pipeline definitions against ``ComponentRegistry``
* **Building** - Constructs Haystack ``Pipeline`` objects from YAML/dict definitions
* **Execution** - Asynchronous pipeline execution
* **Caching** - Version-based pipeline caching for performance

Key Dependencies
----------------

* ``ComponentRegistry`` - Whitelist of allowed Haystack components
* ``PipelineValidator`` - Validates pipeline structure and connections
* ``DocumentContract`` - Enforces required metadata (``celex``, ``eId``)
* ``PipelineRepository`` - Database persistence for pipelines and executions

Execution Flow
--------------

1. Pipeline definition validated via ``PipelineValidator``
2. Documents validated against ``DocumentContract`` 
3. Haystack ``Pipeline`` built from component definitions
4. Pipeline executed with input documents
5. Results persisted via repository layer

.. automodule:: ai4drpm.services.engine.pipeline_service
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