Phase 1 of Migration. Running Scripts

backend/migration/migrate_melody_drafts.py

@@ -0,0 +1,66 @@
+"""
+Phase 1 — Step 1.1: melody_drafts  (SQLite → Postgres)
+
+Run on VPS:
+    docker compose exec backend python -m migration.migrate_melody_drafts
+"""
+
+import asyncio
+import json
+import sys
+
+from sqlalchemy import text
+from sqlalchemy.dialects.postgresql import insert as pg_insert
+
+from melodies.orm import MelodyDraft
+from migration.utils import open_sqlite, AsyncPgSession, parse_dt, parse_json, log_run, pg_count
+
+SCRIPT = "migrate_melody_drafts"
+
+
+async def run() -> None:
+    sqlite = await open_sqlite()
+    rows = await sqlite.execute_fetchall("SELECT * FROM melody_drafts")
+    await sqlite.close()
+
+    source_count = len(rows)
+    print(f"Source (SQLite): {source_count} melody_drafts rows")
+
+    if source_count == 0:
+        print("Nothing to migrate.")
+        await log_run(SCRIPT, 0, 0, notes="source empty")
+        return
+
+    records = []
+    for r in rows:
+        data_raw = r["data"]
+        # SQLite stores data as JSON text; Postgres column is JSONB
+        data = parse_json(data_raw, default={})
+
+        records.append({
+            "id":         r["id"],
+            "status":     r["status"] or "draft",
+            "data":       data,
+            "created_at": parse_dt(r["created_at"]),
+            "updated_at": parse_dt(r["updated_at"]),
+        })
+
+    async with AsyncPgSession() as session:
+        async with session.begin():
+            stmt = pg_insert(MelodyDraft).values(records)
+            stmt = stmt.on_conflict_do_nothing(index_elements=["id"])
+            await session.execute(stmt)
+            dest_count = await pg_count(session, "melody_drafts")
+
+    if dest_count < source_count:
+        msg = f"Count mismatch: source={source_count}  postgres={dest_count}"
+        print(f"ERROR: {msg}", file=sys.stderr)
+        await log_run(SCRIPT, source_count, dest_count, success=False, notes=msg)
+        sys.exit(1)
+
+    print(f"Postgres: {dest_count} rows ✓")
+    await log_run(SCRIPT, source_count, dest_count)
+
+
+if __name__ == "__main__":
+    asyncio.run(run())