mapping mode

DRTML

pattern: mapping
mapping:
  # inputs, outputs, merge — contract in drtml/models/mapping

Dispatch (_PATTERN_RUNNERS["mapping"]) → run_mapping.

Runtime glue

processing/mapping_mode/run.py:

1. compile MappingPlan;
2. open StorageSession;
3. call framework.mapping.build (algorithm is not in the step);
4. emit metrics;
5. write output_manifests_json for downstream.

Algorithms

Module	Role
mapping/build.py	merge
mapping/remap.py	id remap helpers
mapping/read.py	prefetch indexes (mapping_read)
mapping/metrics.py	emit (framework)

Step

DRTML + optional thin hooks re-export only.
Downstream: mapping_read → IdIndex → domain remap by id.

See Cookbook.