feat(config): adopt pydantic for yaml config validation

instill_sdk/__main__.py

@@ -1,10 +1,13 @@
 #!/usr/bin/env python
 
 """Package entry point."""
+import pprint
 
+from instill_sdk.configuration import config
 
 # from instill_sdk.client import
 
 if __name__ == "__main__":  # pragma: no cover
     # main()  # pylint: disable=no-value-for-parameter
-    print("hello world")
+    print("======================Configured Hosts======================")
+    pprint.pprint(config.remotes)

instill_sdk/configuration/__init__.py

@@ -0,0 +1,51 @@
+import os
+import typing as t
+from pathlib import Path
+
+import yaml
+from pydantic import BaseModel
+
+CONFIG_DIR = Path(
+    os.getenv(
+        "INSTILL_SYSTEM_CONFIG_PATH",
+        Path.home() / ".config/instill/",
+    )
+)
+
+
+class _InstillHost(BaseModel):
+    alias: t.Optional[str] = ""
+    url: str
+    token: t.Optional[str] = ""
+
+
+class _Config(BaseModel):
+    remotes: t.Optional[t.List[_InstillHost]] = None
+
+
+class Configuration:
+    def __init__(self) -> None:
+        self._config: _Config
+
+        CONFIG_DIR.mkdir(exist_ok=True)
+
+    @property
+    def remotes(self) -> t.Optional[t.List[_InstillHost]]:
+        return self._config.remotes
+
+    def load(self) -> None:
+        path = CONFIG_DIR / "config.yaml"
+        if not path.exists():
+            self._config = _Config()
+            return
+        try:
+            with open(path, "r", encoding="utf-8") as c:
+                self._config = _Config.model_validate(
+                    yaml.load(c, Loader=yaml.FullLoader)
+                )
+        except Exception as e:
+            raise BaseException(f"Invalid configuration file at '{path}'") from e
+
+
+config = Configuration()
+config.load()