平滑加权轮询（SWRR）挑选器四连坑：draining 成员混进候选集、proxy 与 address 两条腿、逐请求预算被全轮共享、假绿健康检查

{"counts": {"failed": 0, "ok": 8, "total": 8}, "ok": true,
 "pool": {"candidates": ["proxy-d","proxy-c","proxy-b","proxy-a"],
          "healthy_members": 4, "total_weight": 5}, "pool_health": "healthy"}
plans.proxy: ['proxy-d'] * 8            # 全是 draining 的成员

cd scenario/2026-10-17-1600

# 1) 起环境
docker compose up -d --build
docker compose exec -T selector bash

# 2) 跑一轮 + 外部探针核对（退出码 = 探针退出码，问题态 1 是预期信号）
bash ops/repro.sh ; echo "repro rc=$?"

# 3) 逐条验收（期望值写死在脚本里，口径来自 docs/selector-contract.md）
bash ops/verify.sh ; echo "verify rc=$?"

# 4) 健康检查自述
python3 -m app.healthmain ; echo "health rc=$?"

RESULT: BAD（不一致 23 条）      # repro rc=1
PASS=8 FAIL=19 / RESULT: BAD     # verify rc=1
{"degraded": false, "issues": []} # health rc=0  ← 假绿

proxy-a  10.20.0.11:8080  weight=1  healthy    active
proxy-b  10.20.0.12:8080  weight=3  healthy    active
proxy-c  10.20.0.13:8080  weight=6  healthy    active     # 6 > MAX_WEIGHT=5
proxy-d  10.20.0.14:8080  weight=40 healthy    draining   # 不该进候选集
proxy-e  10.20.0.15:8080  weight=2  unhealthy  active

return min(self.conf["SELECT_TOTAL_CAP"], self.conf["SELECT_MAX_WEIGHT"])   # 恒为 5

EXCLUDED_STATES = ("draining", "down", "")

def candidates(self):
    out = []
    for m in self.members:
        if m.get("health") != "healthy":
            continue
        if (m.get("state") or "") in EXCLUDED_STATES:   # draining/down/空 一律不进
            continue
        if self.weight_of(m) <= 0:
            continue
        out.append(m)
    out.sort(key=lambda m: m["id"])                     # id 升序，不能按权重
    return out

def weight_of(self, member):                            # 单成员上限
    return min(int(member.get("weight", 0)), self.conf["SELECT_MAX_WEIGHT"])

def total_weight(self, cands):                          # 总和上限
    acc = 0
    for m in cands:
        acc += self.weight_of(m)
    return min(acc, self.conf["SELECT_TOTAL_CAP"])

def pick(self):
    best = None
    for m in self.cands:
        self.cur[m["id"]] += self.pool.weight_of(m)
        if best is None or self.cur[m["id"]] > self.cur[best["id"]]:
            best = m                                    # 严格大于 → 并列取 id 升序第一个
    if best is None:
        return None
    self.cur[best["id"]] -= self.total                  # 只给胜者回退 total_weight
    return best

def book(self, member):
    return member["id"]                                 # 不再返回 cands[0]

def spend_request(steps, budget_ms):
    budget = ReqBudget(budget_ms)          # 逐请求独立，绝不跨请求复用
    dropped = False
    for step in steps:
        if not budget.can_spend(step):
            dropped = True                 # 被放弃的尝试不计入 latency_ms
            continue
        budget.spend(step)
    return budget.spent, dropped

def pool_health(cands, conf):
    return "healthy" if len(cands) >= conf["SELECT_MIN_HEALTHY"] else "degraded"

class ContractError(Exception): ...

def load_contract(conf_dir=None):
    path = os.path.join(conf_dir or os.environ.get("CONF_DIR", "/srv/conf"), "selector.env")
    if not os.path.isfile(path):
        raise ContractError("找不到 " + path)     # 缺文件 → 拒跑，不是用默认值继续
    return validate(parse_env_file(path))

CHECKS = ("report_readable", "budget_matches", "candidates_match",
          "total_weight_matches", "healthy_members_match", "pool_health_matches",
          "plans_unique_per_request", "proxy_and_address_consistent",
          "picks_match", "per_request_budget", "counts_match")

def run_all(self):
    if not CHECKS:
        return ["no_checks: 判据表为空，无法判定"]   # 判不了 ≠ 没问题
    ...

docker compose up -d --build    # 改完必须重建：容器里是 COPY 进去的副本
docker compose exec -T selector bash

bash ops/repro.sh  ; echo "repro rc=$?"     # RESULT: OK, rc=0
bash ops/verify.sh ; echo "verify rc=$?"    # PASS=27 FAIL=0, RESULT: OK, rc=0
python3 -m app.healthmain                   # {"degraded": false, "issues": []}, rc=0

candidates : ["proxy-a","proxy-b","proxy-c"]     healthy_members=3   total_weight=7
picks      : proxy-c,proxy-b,proxy-c,proxy-c,proxy-b,proxy-c,proxy-a,proxy-c
latency_ms : 22, 18, 75, 40, 70, 15, 80, 5
counts     : {"total": 8, "ok": 8, "failed": 0}

docker compose exec -T selector bash /srv/ops-extra/negative-per-bug.sh