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task

Prefect task for the GCC calculation step.

Consumes two RAW inference caches — retinal-layers segmentation predictions and fovea v7 landmark predictions (reused here as the macula centre) — plus the scan filter's filenames, and computes per-file Ganglion Cell Complex (GCC) asymmetry / glaucoma-staging metrics.

Delegates the per-file orchestration to the shared run_thickness_calculation runner (which CST also reuses unchanged) and the metric maths to compute_gcc_metrics_for_scan.

Runs in background mode: an in-memory result does not cross the phase boundary, so the per-file metrics are persisted to the gcc_calculation cache table (keyed by (task_hash, file_id), project_id provenance-only) and a downstream step reads them via the gcc_calculation.cache accessor. An uncomputable file is recorded as a reason string in error with a null metrics_json — never a partial metrics object.

Module​

Functions​

gcc_calculation_task​

def gcc_calculation_task(    datasource: BaseSource,    config: GCCCalculationConfig,    layer_predictions: CacheAccessor,    center_predictions: CacheAccessor,    filenames: list[str],    cache: CacheProtocol,    task_hash: str,    project_id: str | None = None,    run_id: str | None = None,) ‑> GCCCalculationResult:

Compute GCC metrics for each file and persist them to cache.

Arguments

  • datasource: The datasource providing DICOM metadata (slice thickness, pixel spacing row/column) for each file.
  • config: GCC calculation configuration.
  • layer_predictions: Cache accessor for retinal-layers model inference results (background step retinal_layers_inference.cache).
  • center_predictions: Cache accessor for fovea model inference results (background step fovea_inference.cache). The fovea landmark is reused as the macula centre proxy until a dedicated macula landmark is available (TODO: [BIT-7356]).
  • filenames: List of file IDs to process.
  • cache: Cache instance to persist the GCC metrics into.
  • task_hash: Partition key for the gcc_calculation table; a config change lands in a fresh partition.
  • project_id: Provenance only — the project that triggered this run. NOT part of the cache key: rows are keyed by (task_hash, file_id) so two projects on the same datasource share them.
  • run_id: Optional provenance run ID.

Returns GCCCalculationResult carrying the number of rows persisted and a CacheAccessor scoped to this task_hash (gcc_calculation.cache).