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featurizer

0003 — The φ-bridge is an orchestration-agnostic library

Status: Accepted

Date: 2026-06-14

Deciders: Adolfo De Unánue

Context

Section titled “Context”

The φ-bridge ([[0001-phi-bridge-precompute-causal-boundary]]) does real work: it reads source rows, runs heavy Python, and writes a table. The pipeline standard for these projects is Dagster/Snakemake + dbt — so the question was whether the bridge should embed scheduling, retries, and asset wiring.

Decision

Section titled “Decision”

featurizer/bridge/ is a plain library: BridgeComputer.materialize(conn, ...) takes a live connection and does its I/O synchronously when called. It schedules nothing, owns no assets, and imports no orchestrator. Wiring it as a Dagster asset or Snakemake rule upstream of the SQL run is the caller’s responsibility.

Consequences

Section titled “Consequences”
  • The bridge stays testable with a bare psycopg connection and reusable from any orchestrator (or none) without inversion-of-control ceremony.
  • It does not satisfy the pipeline-orchestration standard on its own; a project using it in production must place the materialize call inside a Dagster asset / Snakemake rule, not call it from an ad-hoc script.
  • Optional heavy dependencies live in the [bridge] extra, so importing the SQL spine never drags in spaCy / sentence-transformers / networkx.

Canonical file: docs/adr/0003-bridge-orchestration-boundary.md