ai-agent-book 精选快照（<2MB 代码与文档，来自 github.com/bojieli/ai-agent-book）

chapter9/gaia-experience/AWorld/aworld/checkpoint/README.md

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+# Checkpoint Module
+
+## Overview
+The Checkpoint module provides a robust and extensible framework for managing state snapshots (checkpoints) in Python applications. It is designed for scenarios where you need to persist, restore, and version the state of a process, session, or task.
+
+```mermaid
+sequenceDiagram
+    participant Application
+    participant CheckpointRepository
+    participant BackendStorage
+
+    Note over Application,BackendStorage: Create and store a checkpoint
+    %% Create and store a checkpoint
+    Application->>CheckpointRepository: create checkpoint
+    CheckpointRepository->>BackendStorage: put(checkpoint)
+    BackendStorage-->>CheckpointRepository: success
+    CheckpointRepository-->>Application: ack
+    
+    Note over Application,BackendStorage: Retrieve the latest checkpoint by session
+
+    %% Retrieve the latest checkpoint by session
+    Application->>CheckpointRepository: get checkpoint by session_id
+    CheckpointRepository->>BackendStorage: get_by_session(session_id)
+    BackendStorage-->>CheckpointRepository: Checkpoint
+    CheckpointRepository-->>Application: Checkpoint
+
+```
+
+## Key Features
+
+- **Structured Data Model**: Uses Pydantic's `BaseModel` for strong typing and validation of checkpoint data and metadata.
+- **Versioning Support**: Built-in version management utilities for checkpoint evolution and comparison.
+- **Extensible Repository Pattern**: Abstract base class (`BaseCheckpointRepository`) defines a standard interface for checkpoint storage, supporting both synchronous and asynchronous operations.
+- **In-Memory Implementation**: Includes a simple, ready-to-use in-memory repository for development and testing.
+- **Utility Functions**: Helper methods for creating, copying, and managing checkpoints.
+
+## Data Structures
+
+```mermaid
+classDiagram
+    class Application {
+        +CheckpointRepository repo
+        +create_checkpoint()
+        +get_checkpoint_by_session()
+    }
+    class CheckpointRepository {
+        +put(checkpoint)
+        +get_by_session(session_id)
+        +delete_by_session(session_id)
+        -BackendStorage backend
+    }
+    class BackendStorage {
+        +put(checkpoint)
+        +get_by_session(session_id)
+        +delete_by_session(session_id)
+    }
+    Application --> CheckpointRepository : uses
+    CheckpointRepository --> BackendStorage : delegates
+    class Checkpoint {
+        +id: str
+        +ts: str
+        +metadata: CheckpointMetadata
+        +values: dict
+        +version: int
+        +parent_id: str
+        +namespace: str
+    }
+    class CheckpointMetadata {
+        +session_id: str
+        +task_id: str
+    }
+    Checkpoint o-- CheckpointMetadata
+    CheckpointRepository o-- Checkpoint
+    BackendStorage o-- Checkpoint
+```
+
+
+## Usage Example
+
+```python
+from aworld.checkpoint import (
+    Checkpoint, CheckpointMetadata, empty_checkpoint, create_checkpoint, InMemoryCheckpointRepository
+)
+
+# Create a new checkpoint
+metadata = CheckpointMetadata(session_id="session-123", task_id="task-456")
+values = {"step": 1, "score": 100}
+checkpoint = create_checkpoint(values=values, metadata=metadata)
+
+# Store and retrieve using the in-memory repository
+repo = InMemoryCheckpointRepository()
+repo.put(checkpoint)
+restored = repo.get(checkpoint.id)
+```
+
+## Extensibility
+- Implement custom repositories by inheriting from `BaseCheckpointRepository` (e.g., for database, file, or cloud storage).
+- Extend versioning logic via the `VersionUtils` class.