chore: import upstream snapshot with attribution

examples/python-ml-experiment-tracker/tracker/config.py

@@ -0,0 +1,70 @@
+from __future__ import annotations
+
+import dataclasses
+import json
+import os
+from pathlib import Path
+from typing import Any
+
+CONFIG_DIR = Path.home() / ".config" / "ml-tracker"
+CONFIG_FILE = CONFIG_DIR / "config.json"
+DEFAULT_SERVER_URL = "http://localhost:7130"
+
+
+@dataclasses.dataclass
+class Config:
+    """Persisted configuration for the tracker CLI, stored at ~/.config/ml-tracker/config.json."""
+
+    server_url: str = DEFAULT_SERVER_URL
+    access_token: str | None = None
+    refresh_token: str | None = None
+    user_email: str | None = None
+
+    def to_dict(self) -> dict[str, Any]:
+        """Serialise the config to a plain dict suitable for JSON encoding."""
+        return dataclasses.asdict(self)
+
+    @classmethod
+    def from_dict(cls, data: dict[str, Any]) -> "Config":
+        """Deserialise a config from a plain dict, applying defaults for missing keys."""
+        return cls(
+            server_url=data.get("server_url", DEFAULT_SERVER_URL),
+            access_token=data.get("access_token"),
+            refresh_token=data.get("refresh_token"),
+            user_email=data.get("user_email"),
+        )
+
+
+def load_config() -> Config:
+    """Load the config from disk, returning defaults if the file does not exist."""
+    if not CONFIG_FILE.exists():
+        return Config()
+    with CONFIG_FILE.open("r") as f:
+        data = json.load(f)
+    return Config.from_dict(data)
+
+
+def save_config(config: Config) -> None:
+    """Atomically write config to disk with 0o600 permissions, protecting token data."""
+    CONFIG_DIR.mkdir(parents=True, exist_ok=True)
+    tmp = CONFIG_FILE.with_suffix(".tmp")
+    fd = os.open(tmp, os.O_WRONLY | os.O_CREAT | os.O_TRUNC, 0o600)
+    with os.fdopen(fd, "w") as f:
+        json.dump(config.to_dict(), f, indent=2)
+    tmp.replace(CONFIG_FILE)
+
+
+def update_tokens(access_token: str, refresh_token: str) -> None:
+    """Reload config from disk, replace both tokens, and save."""
+    cfg = load_config()
+    cfg.access_token = access_token
+    cfg.refresh_token = refresh_token
+    save_config(cfg)
+
+
+def clear_tokens() -> None:
+    """Clear stored access and refresh tokens from the config file."""
+    cfg = load_config()
+    cfg.access_token = None
+    cfg.refresh_token = None
+    save_config(cfg)