feat: rebuild work queue api with fastapi and postgres

app/db.py

@@ -0,0 +1,131 @@
+from __future__ import annotations
+
+import json
+from contextlib import contextmanager
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Any
+from uuid import UUID, uuid4
+
+import psycopg
+from fastapi import HTTPException
+from psycopg.rows import dict_row
+
+from app.config import settings
+
+MIGRATION_PATH = Path(__file__).parent / "migrations" / "001_initial.sql"
+TERMINAL_STATUSES = {"completed", "failed", "cancelled"}
+VALID_TRANSITIONS = {
+    "queued": {"dispatched", "cancelled"},
+    "dispatched": {"in_progress", "cancelled"},
+    "in_progress": {"blocked", "completed", "failed"},
+    "blocked": {"in_progress", "completed", "failed"},
+    "completed": set(),
+    "failed": set(),
+    "cancelled": set(),
+}
+
+
+def utcnow() -> datetime:
+    return datetime.now(timezone.utc).replace(microsecond=0)
+
+
+@contextmanager
+def get_conn():
+    with psycopg.connect(settings.database_url, row_factory=dict_row) as conn:
+        yield conn
+
+
+def run_migrations() -> None:
+    with get_conn() as conn:
+        conn.execute(MIGRATION_PATH.read_text())
+        conn.commit()
+
+
+def _parse_payload(value: Any) -> dict[str, Any] | None:
+    if value is None:
+        return None
+    if isinstance(value, dict):
+        return value
+    return json.loads(value)
+
+
+def _normalize_work_row(row: dict[str, Any]) -> dict[str, Any]:
+    row["payload"] = _parse_payload(row.get("payload"))
+    row.setdefault("dispatch_log", [])
+    return row
+
+
+def fetch_project_or_404(conn: psycopg.Connection, project_id: str | UUID) -> dict[str, Any]:
+    row = conn.execute(
+        "SELECT id, name, external_ref, created_at, updated_at FROM projects WHERE id = %s",
+        (str(project_id),),
+    ).fetchone()
+    if row is None:
+        raise HTTPException(status_code=404, detail="project not found")
+    return row
+
+
+def fetch_work_or_404(conn: psycopg.Connection, work_id: str | UUID) -> dict[str, Any]:
+    row = conn.execute(
+        """
+        SELECT id, project_id, type, description, payload, priority, status, assigned_agent,
+               created_by, created_at, updated_at, completed_at, outcome, notes
+        FROM work_items WHERE id = %s
+        """,
+        (str(work_id),),
+    ).fetchone()
+    if row is None:
+        raise HTTPException(status_code=404, detail="work item not found")
+    return _normalize_work_row(row)
+
+
+def fetch_dispatch_log(conn: psycopg.Connection, work_id: str | UUID) -> list[dict[str, Any]]:
+    rows = conn.execute(
+        """
+        SELECT id, work_item_id, dispatched_at, agent, completed_at, outcome
+        FROM dispatch_log WHERE work_item_id = %s ORDER BY dispatched_at ASC
+        """,
+        (str(work_id),),
+    ).fetchall()
+    return rows
+
+
+def validate_transition(current: str, new: str, assigned_agent: str | None, outcome: str | None, notes: str | None) -> None:
+    if new not in VALID_TRANSITIONS[current]:
+        raise HTTPException(status_code=400, detail=f"invalid status transition: {current} -> {new}")
+    if current == "queued" and new == "dispatched" and not assigned_agent:
+        raise HTTPException(status_code=400, detail="assigned_agent is required for queued -> dispatched")
+    if new == "blocked" and not (notes or "").strip():
+        raise HTTPException(status_code=400, detail="notes are required when status is blocked")
+    if new in TERMINAL_STATUSES and not outcome:
+        raise HTTPException(status_code=400, detail="outcome is required for terminal statuses")
+    if new == "completed" and outcome != "success":
+        raise HTTPException(status_code=400, detail="completed requires outcome=success")
+    if new == "failed" and outcome != "failed":
+        raise HTTPException(status_code=400, detail="failed requires outcome=failed")
+    if new == "cancelled" and outcome != "cancelled":
+        raise HTTPException(status_code=400, detail="cancelled requires outcome=cancelled")
+
+
+def create_dispatch_log(conn: psycopg.Connection, work_item_id: str, agent: str, dispatched_at: datetime) -> None:
+    conn.execute(
+        "INSERT INTO dispatch_log (id, work_item_id, dispatched_at, agent) VALUES (%s, %s, %s, %s)",
+        (str(uuid4()), work_item_id, dispatched_at, agent),
+    )
+
+
+def complete_dispatch_log(conn: psycopg.Connection, work_item_id: str, completed_at: datetime, outcome: str) -> None:
+    conn.execute(
+        """
+        UPDATE dispatch_log
+        SET completed_at = %s, outcome = %s
+        WHERE id = (
+            SELECT id FROM dispatch_log
+            WHERE work_item_id = %s AND completed_at IS NULL
+            ORDER BY dispatched_at DESC
+            LIMIT 1
+        )
+        """,
+        (completed_at, outcome, work_item_id),
+    )