Initial commit: add .gitignore and README

fusionagi/core/json_file_backend.py

@@ -0,0 +1,69 @@
+"""JSON file persistence backend for StateManager."""
+
+import json
+from pathlib import Path
+from typing import Any
+
+from fusionagi.schemas.task import Task, TaskState
+from fusionagi.core.persistence import StateBackend
+from fusionagi._logger import logger
+
+
+class JsonFileBackend(StateBackend):
+    """
+    StateBackend that persists tasks and traces to a JSON file.
+
+    Use with StateManager(backend=JsonFileBackend(path="state.json")).
+    File is created on first write; directory must exist or be creatable.
+    """
+
+    def __init__(self, path: str | Path) -> None:
+        self._path = Path(path)
+        self._tasks: dict[str, dict[str, Any]] = {}
+        self._traces: dict[str, list[dict[str, Any]]] = {}
+        self._load()
+
+    def _load(self) -> None:
+        if not self._path.exists():
+            return
+        try:
+            data = json.loads(self._path.read_text(encoding="utf-8"))
+            self._tasks = data.get("tasks", {})
+            self._traces = data.get("traces", {})
+        except Exception as e:
+            logger.warning("JsonFileBackend load failed", extra={"path": str(self._path), "error": str(e)})
+
+    def _save(self) -> None:
+        self._path.parent.mkdir(parents=True, exist_ok=True)
+        data = {"tasks": self._tasks, "traces": self._traces}
+        self._path.write_text(json.dumps(data, indent=2), encoding="utf-8")
+
+    def get_task(self, task_id: str) -> Task | None:
+        raw = self._tasks.get(task_id)
+        if raw is None:
+            return None
+        try:
+            return Task.model_validate(raw)
+        except Exception:
+            return None
+
+    def set_task(self, task: Task) -> None:
+        self._tasks[task.task_id] = task.model_dump(mode="json")
+        self._save()
+
+    def get_task_state(self, task_id: str) -> TaskState | None:
+        task = self.get_task(task_id)
+        return task.state if task else None
+
+    def set_task_state(self, task_id: str, state: TaskState) -> None:
+        task = self.get_task(task_id)
+        if task:
+            updated = task.model_copy(update={"state": state})
+            self.set_task(updated)
+
+    def append_trace(self, task_id: str, entry: dict[str, Any]) -> None:
+        self._traces.setdefault(task_id, []).append(entry)
+        self._save()
+
+    def get_trace(self, task_id: str) -> list[dict[str, Any]]:
+        return list(self._traces.get(task_id, []))