From 2242d66b8c287f4074e216011f0b5eb6c0b35b9b Mon Sep 17 00:00:00 2001
From: Mika <kontakt@donau2space.de>
Date: Tue, 24 Mar 2026 11:10:14 +0000
Subject: [PATCH] Add retry_tail_analysis/src/retry_tail_analysis/core.py

---
 .../src/retry_tail_analysis/core.py           | 65 +++++++++++++++++++
 1 file changed, 65 insertions(+)
 create mode 100644 retry_tail_analysis/src/retry_tail_analysis/core.py

diff --git a/retry_tail_analysis/src/retry_tail_analysis/core.py b/retry_tail_analysis/src/retry_tail_analysis/core.py
new file mode 100644
index 0000000..29ada55
--- /dev/null
+++ b/retry_tail_analysis/src/retry_tail_analysis/core.py
@@ -0,0 +1,65 @@
+from __future__ import annotations
+
+import logging
+from dataclasses import dataclass
+from statistics import mean
+from typing import List
+
+
+logger = logging.getLogger(__name__)
+
+
+class DataValidationError(ValueError):
+    """Custom exception for invalid ExperimentData."""
+
+
+@dataclass
+class ExperimentData:
+    """Represents one experimental run data entry."""
+
+    run_id: str
+    retry_tailp99: float
+    threshold: float
+
+    def __post_init__(self) -> None:
+        if not isinstance(self.run_id, str):
+            raise DataValidationError(f"run_id must be str, got {type(self.run_id).__name__}")
+        if not isinstance(self.retry_tailp99, (int, float)):
+            raise DataValidationError(
+                f"retry_tailp99 must be numeric, got {type(self.retry_tailp99).__name__}"
+            )
+        if not isinstance(self.threshold, (int, float)):
+            raise DataValidationError(f"threshold must be numeric, got {type(self.threshold).__name__}")
+        if self.retry_tailp99 < 0 or self.threshold < 0:
+            raise DataValidationError("Values for retry_tailp99 and threshold must be non-negative.")
+
+
+def analyze_retry_tail(data: List[ExperimentData]) -> float:
+    """Calculates aggregated retry_tailp99 from ExperimentData.
+
+    Args:
+        data: List of ExperimentData instances.
+
+    Returns:
+        Aggregated average retry_tailp99 value (float).
+    """
+    assert isinstance(data, list), "Input data must be a list of ExperimentData instances"
+    if not data:
+        raise ValueError("Data list must not be empty.")
+
+    validated_data = []
+    for item in data:
+        if not isinstance(item, ExperimentData):
+            raise TypeError("All items must be ExperimentData instances.")
+        validated_data.append(item)
+
+    tail_values = [d.retry_tailp99 for d in validated_data]
+    agg_value = float(mean(tail_values))
+
+    # Check for threshold exceedances
+    exceed_count = sum(1 for d in validated_data if d.retry_tailp99 >= d.threshold)
+
+    logger.debug("Aggregated retry_tailp99: %.4f", agg_value)
+    logger.info("%d of %d runs exceed threshold.", exceed_count, len(validated_data))
+
+    return agg_value