eafonyang
148 lines
4.0 KiB
Go
148 lines
4.0 KiB
Go
package cache
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import (
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"context"
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"encoding/json"
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"fmt"
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"time"
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"github.com/redis/go-redis/v9"
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)
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const (
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curveLockTTL = 10 * time.Second
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curveLockRetryDelay = 100 * time.Millisecond
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curveLockMaxRetries = 50
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)
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// CurveCache 曲线数据缓存（Redis Hash）
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type CurveCache struct {
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rdb *redis.Client
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}
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func NewCurveCache(rdb *redis.Client) *CurveCache {
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return &CurveCache{rdb: rdb}
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}
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// Get 从 Redis Hash 中获取曲线缓存
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func (c *CurveCache) Get(ctx context.Context, brand, name, target string) (string, error) {
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key := brand + " " + name
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val, err := c.rdb.HGet(ctx, key, target).Result()
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if err == redis.Nil {
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return "", nil
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}
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if err != nil {
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return "", fmt.Errorf("hget curve cache: %w", err)
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}
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return val, nil
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}
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// Set 将曲线数据存入 Redis Hash
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func (c *CurveCache) Set(ctx context.Context, brand, name, target, data string) error {
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key := brand + " " + name
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return c.rdb.HSet(ctx, key, target, data).Err()
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}
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// GetFR 直接获取独立存储的 fr 数据（用于 modelCurve 接口）
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func (c *CurveCache) GetFR(ctx context.Context, brand, name string) (string, error) {
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key := brand + " " + name
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val, err := c.rdb.HGet(ctx, key, "__fr").Result()
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if err == redis.Nil {
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return "", nil
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}
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if err != nil {
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return "", fmt.Errorf("hget curve fr: %w", err)
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}
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return val, nil
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}
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// GetWithFR 获取 target 缓存数据并合并独立存储的 fr 数据
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// 兼容旧缓存：若 target 数据中已有 fr 字段则直接返回
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func (c *CurveCache) GetWithFR(ctx context.Context, brand, name, target string) (string, error) {
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key := brand + " " + name
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targetData, err := c.rdb.HGet(ctx, key, target).Result()
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if err == redis.Nil {
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return "", nil
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}
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if err != nil {
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return "", fmt.Errorf("hget curve target: %w", err)
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}
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if targetData == "" {
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return "", nil
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}
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// 旧缓存兼容：已有 fr 字段无需合并
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var check map[string]json.RawMessage
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if err := json.Unmarshal([]byte(targetData), &check); err == nil {
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if _, hasFR := check["fr"]; hasFR {
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return targetData, nil
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}
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}
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// 新缓存：从 __fr 字段读取 fr 数据并合并
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frData, err := c.rdb.HGet(ctx, key, "__fr").Result()
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if err == redis.Nil || frData == "" {
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return targetData, nil
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}
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if err != nil {
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return targetData, nil
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}
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var result map[string]json.RawMessage
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if err := json.Unmarshal([]byte(targetData), &result); err != nil {
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return targetData, nil
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}
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result["fr"] = json.RawMessage(frData)
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merged, err := json.Marshal(result)
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if err != nil {
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return targetData, nil
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}
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return string(merged), nil
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}
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// AcquireLock 获取分布式锁（SETNX），防止并发请求同一个曲线数据
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func (c *CurveCache) AcquireLock(ctx context.Context, brand, name, target string) (bool, error) {
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lockKey := brand + " " + name + ":" + target + ":lock"
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return c.rdb.SetNX(ctx, lockKey, "locked", curveLockTTL).Result()
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}
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// ReleaseLock 释放分布式锁
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func (c *CurveCache) ReleaseLock(ctx context.Context, brand, name, target string) error {
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lockKey := brand + " " + name + ":" + target + ":lock"
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return c.rdb.Del(ctx, lockKey).Err()
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}
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// GetWithLock 获取缓存数据，缓存不存在时尝试加锁后重新获取
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// 返回值: (data, acquired, error)
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// - data: 缓存数据（空字符串表示无数据）
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// - acquired: 是否成功获取锁（缓存不存在时需要加锁）
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func (c *CurveCache) GetWithLock(ctx context.Context, brand, name, target string) (data string, acquired bool, err error) {
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// 先查缓存
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data, err = c.Get(ctx, brand, name, target)
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if err != nil {
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return "", false, err
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}
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if data != "" {
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return data, false, nil // 缓存命中
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}
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// 缓存不存在，尝试加锁
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acquired, err = c.AcquireLock(ctx, brand, name, target)
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if err != nil {
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return "", false, fmt.Errorf("acquire curve lock: %w", err)
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}
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if acquired {
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// 加锁成功，再次检查缓存（双重检查）
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data, err = c.Get(ctx, brand, name, target)
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if err != nil {
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return "", true, err
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}
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return data, true, nil
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}
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// 未获取锁，等待后重试
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return "", false, nil
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}
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