built rag search setup

python/ebook_search/timing.py

@@ -0,0 +1,36 @@
+"""Runtime timing helpers for EPUB search."""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from time import perf_counter
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from collections.abc import Callable
+
+
+@dataclass(frozen=True)
+class RuntimeStep:
+    """Elapsed runtime for one named search step."""
+
+    name: str
+    duration_ms: float
+    counts_toward_total: bool = True
+
+
+def runtime_step_from_start(name: str, start_seconds: float) -> RuntimeStep:
+    """Create a runtime step from a prior perf_counter timestamp."""
+    return RuntimeStep(name=name, duration_ms=(perf_counter() - start_seconds) * 1000)
+
+
+def timed_result[T, **P](
+    name: str,
+    operation: Callable[P, T],
+    *args: P.args,
+    **kwargs: P.kwargs,
+) -> tuple[T, RuntimeStep]:
+    """Run an operation and return its result plus elapsed runtime."""
+    start_seconds = perf_counter()
+    result = operation(*args, **kwargs)
+    return result, runtime_step_from_start(name, start_seconds)