Initial commit

src/meshbot/config.py

@@ -0,0 +1,74 @@
+"""Application settings loaded from TOML with env-var overrides."""
+
+from __future__ import annotations
+
+import os
+from pathlib import Path
+
+from pydantic import BaseModel, Field
+from pydantic_settings import (
+    BaseSettings,
+    PydanticBaseSettingsSource,
+    SettingsConfigDict,
+    TomlConfigSettingsSource,
+)
+
+
+class MeshCoreCfg(BaseModel):
+    serial_port: str
+    baud_rate: int = 115200
+
+
+class LLMCfg(BaseModel):
+    base_url: str
+    api_key: str = "not-needed"
+    model: str
+    system_prompt: str = (
+        "You are a concise assistant on a low-bandwidth mesh radio. "
+        "Replies must be brief — under 180 bytes."
+    )
+    temperature: float = 0.7
+    request_timeout_seconds: float = 60.0
+
+
+class StorageCfg(BaseModel):
+    sqlite_path: Path = Path("data/meshbot.db")
+
+
+class MessageCfg(BaseModel):
+    max_bytes: int = Field(default=184, gt=0)
+
+
+def _toml_path() -> Path:
+    return Path(os.environ.get("MESHBOT_CONFIG", "config.toml"))
+
+
+class Settings(BaseSettings):
+    meshcore: MeshCoreCfg
+    llm: LLMCfg
+    storage: StorageCfg = StorageCfg()
+    message: MessageCfg = MessageCfg()
+
+    model_config = SettingsConfigDict(
+        env_prefix="MESHBOT_",
+        env_nested_delimiter="__",
+        toml_file=_toml_path(),
+        extra="ignore",
+    )
+
+    @classmethod
+    def settings_customise_sources(
+        cls,
+        settings_cls: type[BaseSettings],
+        init_settings: PydanticBaseSettingsSource,
+        env_settings: PydanticBaseSettingsSource,
+        dotenv_settings: PydanticBaseSettingsSource,
+        file_secret_settings: PydanticBaseSettingsSource,
+    ) -> tuple[PydanticBaseSettingsSource, ...]:
+        # Order = priority (highest first): init args > env > TOML > secrets.
+        return (
+            init_settings,
+            env_settings,
+            TomlConfigSettingsSource(settings_cls),
+            file_secret_settings,
+        )