feat(fc3c): migration 0013 — download_event.metadata + import_settings downloader fields

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

alembic/versions/0013_fc3c_download_event_metadata.py

@@ -0,0 +1,52 @@
+"""fc3c: download_event.metadata + import_settings downloader fields
+
+Revision ID: 0013
+Revises: 0012
+Create Date: 2026-05-20
+
+Additive only. download_event.metadata is the rich JSONB blob FC-3c
+populates per run (run_stats, stdout/stderr, quarantined paths, import
+summary). import_settings gains two operator-tunable downloader knobs:
+download_rate_limit_seconds (gallery-dl extractor.sleep) and
+download_validate_files (toggle the magic-byte validator).
+"""
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+from alembic import op
+from sqlalchemy.dialects import postgresql
+
+revision: str = "0013"
+down_revision: Union[str, None] = "0012"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.add_column(
+        "download_event",
+        sa.Column(
+            "metadata", postgresql.JSONB,
+            nullable=False, server_default=sa.text("'{}'::jsonb"),
+        ),
+    )
+    op.add_column(
+        "import_settings",
+        sa.Column(
+            "download_rate_limit_seconds", sa.Float(),
+            nullable=False, server_default="3.0",
+        ),
+    )
+    op.add_column(
+        "import_settings",
+        sa.Column(
+            "download_validate_files", sa.Boolean(),
+            nullable=False, server_default=sa.true(),
+        ),
+    )
+
+
+def downgrade() -> None:
+    op.drop_column("import_settings", "download_validate_files")
+    op.drop_column("import_settings", "download_rate_limit_seconds")
+    op.drop_column("download_event", "metadata")

backend/app/models/download_event.py

@@ -2,7 +2,9 @@
 
 from datetime import datetime
 
+import sqlalchemy as sa
 from sqlalchemy import BigInteger, DateTime, ForeignKey, Integer, String, Text, func
+from sqlalchemy.dialects.postgresql import JSONB
 from sqlalchemy.orm import Mapped, mapped_column
 
 from .base import Base
@@ -18,7 +20,7 @@ class DownloadEvent(Base):
     post_id: Mapped[int | None] = mapped_column(
         ForeignKey("post.id", ondelete="SET NULL"), nullable=True, index=True
     )
-    status: Mapped[str] = mapped_column(String(32), nullable=False)  # pending|running|ok|error
+    status: Mapped[str] = mapped_column(String(32), nullable=False)  # pending|running|ok|error|skipped
     started_at: Mapped[datetime] = mapped_column(
         DateTime(timezone=True), nullable=False, server_default=func.now()
     )
@@ -26,3 +28,7 @@ class DownloadEvent(Base):
     bytes_downloaded: Mapped[int] = mapped_column(BigInteger, nullable=False, default=0)
     files_count: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
     error: Mapped[str | None] = mapped_column(Text, nullable=True)
+    metadata_: Mapped[dict] = mapped_column(
+        "metadata", JSONB, nullable=False, default=dict,
+        server_default=sa.text("'{}'::jsonb"),
+    )

backend/app/models/import_settings.py

@@ -30,3 +30,11 @@ class ImportSettings(Base):
     single_color_tolerance: Mapped[int] = mapped_column(Integer, nullable=False, default=30)
 
     phash_threshold: Mapped[int] = mapped_column(Integer, nullable=False, default=10)
+
+    # FC-3c downloader knobs
+    download_rate_limit_seconds: Mapped[float] = mapped_column(
+        Float, nullable=False, default=3.0
+    )
+    download_validate_files: Mapped[bool] = mapped_column(
+        Boolean, nullable=False, default=True
+    )

tests/test_migration_0013.py

@@ -0,0 +1,31 @@
+import pytest
+from sqlalchemy import inspect, select
+
+from backend.app.models import ImportSettings
+
+pytestmark = pytest.mark.integration
+
+
+@pytest.mark.asyncio
+async def test_download_event_has_metadata(db):
+    cols = await db.run_sync(
+        lambda s: {c["name"]: c for c in inspect(s.bind).get_columns("download_event")}
+    )
+    assert "metadata" in cols
+    assert cols["metadata"]["nullable"] is False
+
+
+@pytest.mark.asyncio
+async def test_import_settings_has_downloader_fields(db):
+    cols = await db.run_sync(
+        lambda s: {c["name"]: c for c in inspect(s.bind).get_columns("import_settings")}
+    )
+    assert "download_rate_limit_seconds" in cols
+    assert "download_validate_files" in cols
+
+
+@pytest.mark.asyncio
+async def test_import_settings_defaults(db):
+    row = (await db.execute(select(ImportSettings).where(ImportSettings.id == 1))).scalar_one()
+    assert row.download_rate_limit_seconds == 3.0
+    assert row.download_validate_files is True