feat(config): add environment-driven configuration module and integrate with metrics startup

app.py

@@ -4,10 +4,17 @@ from fastapi.staticfiles import StaticFiles
 from pathlib import Path
 import traceback
 import time
-from metrics import metrics
+from metrics import metrics as _metrics_singleton, Metrics
+from config import config
 
 app = FastAPI(title="Mirage Phase 1+2 Scaffold")
 
+# Potentially reconfigure metrics based on config
+if config.metrics_fps_window != 30:  # default in metrics module
+    metrics = Metrics(fps_window=config.metrics_fps_window)
+else:
+    metrics = _metrics_singleton
+
 # Mount the static directory
 static_dir = Path(__file__).parent / "static"
 app.mount("/static", StaticFiles(directory=str(static_dir)), name="static")
@@ -73,6 +80,12 @@ async def get_metrics():
     return metrics.snapshot()
 
 
+@app.on_event("startup")
+async def log_config():
+    # Simple startup log of configuration
+    print("[config]", config.as_dict())
+
+
 # Note: The Dockerfile / README launch with: uvicorn app:app --port 7860
 if __name__ == "__main__":  # Optional direct run helper
     import uvicorn  # type: ignore

config.py

@@ -0,0 +1,56 @@
+from __future__ import annotations
+
+import os
+from dataclasses import dataclass
+from typing import Any
+
+
+def _get_int(name: str, default: int) -> int:
+    val = os.getenv(name)
+    if val is None:
+        return default
+    try:
+        return int(val)
+    except ValueError:
+        return default
+
+
+def _get_bool(name: str, default: bool) -> bool:
+    val = os.getenv(name)
+    if val is None:
+        return default
+    val_lower = val.lower().strip()
+    if val_lower in {"1", "true", "yes", "on"}:
+        return True
+    if val_lower in {"0", "false", "no", "off"}:
+        return False
+    return default
+
+
+@dataclass(frozen=True)
+class Config:
+    chunk_ms: int = 160
+    voice_enable: bool = False
+    video_max_fps: int = 10
+    metrics_fps_window: int = 30
+
+    @staticmethod
+    def load() -> "Config":
+        return Config(
+            chunk_ms=_get_int("MIRAGE_CHUNK_MS", 160),
+            voice_enable=_get_bool("MIRAGE_VOICE_ENABLE", False),
+            video_max_fps=_get_int("MIRAGE_VIDEO_MAX_FPS", 10),
+            metrics_fps_window=_get_int("MIRAGE_METRICS_FPS_WINDOW", 30),
+        )
+
+    def as_dict(self) -> dict[str, Any]:  # JSON-friendly
+        return {
+            "chunk_ms": self.chunk_ms,
+            "voice_enable": self.voice_enable,
+            "video_max_fps": self.video_max_fps,
+            "metrics_fps_window": self.metrics_fps_window,
+        }
+
+
+# Eagerly loaded singleton pattern (can be reloaded manually if needed)
+config = Config.load()