private RefreshResult HandleFetchedSuccess()

in aliyun-net-credentials/Provider/RefreshCachedSupplier.cs [144:205]
53 lines of code
7 McCabe index (conditional complexity)

        private RefreshResult<T> HandleFetchedSuccess(RefreshResult<T> value)
        {
            Logger.Debug(string.Format("Refresh credentials successfully, retrieved value is {0}, cached value is {1}",
                value, this.cachedValue));
            Interlocked.Exchange(ref consecutiveRefreshFailures, 0);
            var now = DateTime.UtcNow.GetTimeMillis();
            // 过期时间大于15分钟，不用管
            if (now < value.StaleTime)
            {
                Logger.Debug(string.Format("Retrieved value stale time is {0}. Using staleTime of {1}",
                    ParameterHelper.FormatIso8601Date(value.StaleTime),
                    ParameterHelper.FormatIso8601Date(value.StaleTime)));
                return value;
            }

            // 不足或等于15分钟，但未过期，下次会再次刷新
            if (now < value.StaleTime + StaleTime)
            {
                Logger.Warn(string.Format("Retrieved value stale time is %s in the past ({0}). Using staleTime of {1}",
                    ParameterHelper.FormatIso8601Date(value.StaleTime),
                    ParameterHelper.FormatIso8601Date(now)));
                return value.ToBuilder().StaleTime(now).Build();
            }

            Logger.Warn(string.Format(
                "Retrieved value expiration time of the credential is in the past ({0}). Trying use the cached value.",
                ParameterHelper.FormatIso8601Date(value.StaleTime + StaleTime)));

            // 已过期，看缓存，缓存若大于15分钟，返回缓存，若小于15分钟，则根据策略判断是立刻重试还是稍后重试
            if (this.cachedValue == null)
            {
                throw new CredentialException("No cached value was found.");
            }
            if (now < this.cachedValue.StaleTime)
            {
                Logger.Warn(string.Format("Cached value staleTime is {0}. Using staleTime of {1}",
                    ParameterHelper.FormatIso8601Date(this.cachedValue.StaleTime),
                    ParameterHelper.FormatIso8601Date(this.cachedValue.StaleTime)));
                return this.cachedValue;
            }

            switch (this.staleValueBehavior)
            {
                case StaleValueBehavior.Strict:
                    // 立马重试
                    Logger.Warn(string.Format(
                        "Cached value expiration is in the past ({0}). Using expiration of {1}",
                        value.StaleTime, now + 1000));
                    return this.cachedValue.ToBuilder().StaleTime(now + 1000).Build();
                case StaleValueBehavior.Allow:
                    //一分钟左右重试一次
                    var waitUntilNextRefresh = 50 * 1000 + jitter.Next(20 * 1000 + 1);
                    var nextRefreshTime = now + waitUntilNextRefresh;
                    Logger.Warn(string.Format(
                        "Cached value expiration has been extended to {0} because the downstream service returned a time in the past: {1}",
                        nextRefreshTime, value.StaleTime));
                    return this.cachedValue.ToBuilder().StaleTime(nextRefreshTime).Build();
                default:
                    throw new ArgumentException(string.Format("Unknown stale-value-behavior: {0}",
                        this.staleValueBehavior));
            }
        }