新功能：个性化推荐算法

server/app/features/personalized_reco/observability/builder.py

@@ -0,0 +1,136 @@
+from __future__ import annotations
+
+import logging
+from datetime import datetime
+from typing import Any, Optional
+
+from app.features.personalized_reco.observability.types import MissingFields, RecoMeta, Scene
+from app.features.personalized_reco.observability.utils import compute_empty_reason, compute_missing_fields
+
+logger = logging.getLogger(__name__)
+
+
+def _non_negative_int(value: Any, *, default: int = 0) -> int:
+    try:
+        n = int(value)
+    except Exception:
+        return int(default)
+    return max(0, int(n))
+
+
+class RecoMetaBuilder:
+    """
+    在推荐 pipeline 中逐阶段填充 RecoMeta，避免“散落字段/散落日志”。
+
+    说明（V1）：
+    - set 调用允许任意顺序；build 时会做防御式兜底与单调性修正
+    - 单调性约束：raw >= after_hard_filter >= after_dedup >= after_freqcap >= served_k
+    """
+
+    def __init__(self, *, scene: Scene, user_profile: object, k: int, now: Optional[datetime] = None) -> None:
+        self.scene: Scene = scene
+        self.user_profile = user_profile
+        self.k = _non_negative_int(k, default=0)
+        self.now = now
+
+        self._raw: Optional[int] = None
+        self._after_hard: Optional[int] = None
+        self._after_dedup: Optional[int] = None
+        self._after_freqcap: Optional[int] = None
+        self._served_k: Optional[int] = None
+        self._fallback_level_final: Optional[int] = None
+
+        self._risk_filtered_count_by_flag: dict[str, int] = {}
+        self._freqcap_filtered_counts: dict[str, int] = {}
+        self._config_snapshot: dict[str, Any] = {}
+
+    def set_candidate_pool_size_raw(self, n: Any) -> "RecoMetaBuilder":
+        self._raw = _non_negative_int(n)
+        return self
+
+    def set_after_hard_filter(self, n: Any, *, risk_filtered_count_by_flag: Optional[dict[str, Any]] = None) -> "RecoMetaBuilder":
+        self._after_hard = _non_negative_int(n)
+        if risk_filtered_count_by_flag:
+            self._risk_filtered_count_by_flag = {str(k): _non_negative_int(v) for k, v in risk_filtered_count_by_flag.items()}
+        return self
+
+    def set_after_dedup(self, n: Any) -> "RecoMetaBuilder":
+        self._after_dedup = _non_negative_int(n)
+        return self
+
+    def set_after_freqcap(self, n: Any, *, freqcap_filtered_counts: Optional[dict[str, Any]] = None) -> "RecoMetaBuilder":
+        self._after_freqcap = _non_negative_int(n)
+        if freqcap_filtered_counts:
+            self._freqcap_filtered_counts = {str(k): _non_negative_int(v) for k, v in freqcap_filtered_counts.items()}
+        return self
+
+    def set_fallback_level_final(self, level: Any, *, reason: Optional[str] = None) -> "RecoMetaBuilder":
+        # reason 预留，V1 先不入 meta（可放入 config_snapshot 或后续字段）
+        self._fallback_level_final = _non_negative_int(level, default=0)
+        if reason:
+            self._config_snapshot.setdefault("fallback_trigger_reason", str(reason))
+        return self
+
+    def set_served_k(self, n: Any) -> "RecoMetaBuilder":
+        self._served_k = _non_negative_int(n)
+        return self
+
+    def set_config_snapshot(self, snapshot: dict[str, Any]) -> "RecoMetaBuilder":
+        self._config_snapshot = dict(snapshot or {})
+        return self
+
+    def build(self) -> RecoMeta:
+        missing: MissingFields = compute_missing_fields(self.user_profile)
+        conf_u = getattr(self.user_profile, "profile_confidence", 1.0)
+        try:
+            conf_u_f = float(conf_u)
+        except Exception:
+            conf_u_f = 1.0
+        if conf_u_f != conf_u_f:
+            conf_u_f = 1.0
+
+        raw = self._raw if self._raw is not None else 0
+        after_hard = self._after_hard if self._after_hard is not None else raw
+        after_dedup = self._after_dedup if self._after_dedup is not None else after_hard
+        after_freqcap = self._after_freqcap if self._after_freqcap is not None else after_dedup
+        served_k = self._served_k if self._served_k is not None else 0
+
+        # 防御式单调性修正（以最保守值输出）
+        if after_hard > raw:
+            logger.debug("after_hard_filter(%s) > raw(%s)，已修正为 raw", after_hard, raw)
+            after_hard = raw
+        if after_dedup > after_hard:
+            logger.debug("after_dedup(%s) > after_hard_filter(%s)，已修正为 after_hard_filter", after_dedup, after_hard)
+            after_dedup = after_hard
+        if after_freqcap > after_dedup:
+            logger.debug("after_freqcap(%s) > after_dedup(%s)，已修正为 after_dedup", after_freqcap, after_dedup)
+            after_freqcap = after_dedup
+        if served_k > after_freqcap:
+            logger.debug("served_k(%s) > after_freqcap(%s)，已修正为 after_freqcap", served_k, after_freqcap)
+            served_k = after_freqcap
+
+        fallback_level_final = self._fallback_level_final if self._fallback_level_final is not None else 0
+
+        empty_reason = compute_empty_reason(
+            served_k=served_k,
+            candidate_pool_size_raw=raw,
+            candidate_pool_size_after_hard_filter=after_hard,
+            candidate_pool_size_after_freqcap=after_freqcap,
+        )
+
+        return RecoMeta(
+            scene=self.scene,
+            candidate_pool_size_raw=int(raw),
+            candidate_pool_size_after_hard_filter=int(after_hard),
+            candidate_pool_size_after_dedup=int(after_dedup),
+            candidate_pool_size_after_freqcap=int(after_freqcap),
+            fallback_level_final=int(fallback_level_final),
+            served_k=int(served_k),
+            empty_reason=empty_reason,
+            conf_U=float(conf_u_f),
+            missing_fields=missing,
+            risk_filtered_count_by_flag=dict(self._risk_filtered_count_by_flag),
+            freqcap_filtered_counts=dict(self._freqcap_filtered_counts),
+            config_snapshot=dict(self._config_snapshot),
+        )
+