111 lines
3.1 KiB
Go
111 lines
3.1 KiB
Go
// Package cache implement a simple cache redis client.
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// It define a type [Cache] that represent the cache client and
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// It define the methods Get to get a valur from a cache key.
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package cache
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import (
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"context"
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"errors"
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"fmt"
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"time"
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"github.com/go-redis/redis/v8"
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"go.uber.org/zap"
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)
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var (
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ErrCacheNotEnabled = errors.New("CACHE NOT ENABLED")
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ErrNotFound = errors.New("KEY NOT FOUND IN CACHE")
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ErrInternal = errors.New("INTERNAL CACHE ERROR")
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)
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// CacheClient redis cache client.
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type CacheClient struct {
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Client *redis.Client
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Enabled bool
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logger *zap.Logger
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Prefix string
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}
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// Cache is the interface for cache client.
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type Cache interface {
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CacheReadable
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CacheWriteable
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}
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// CacheWriteable is the interface for write cache.
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type CacheWriteable interface {
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Set(ctx context.Context, key string, value interface{}, expirations time.Duration) error
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}
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// CacheReadable is the interface for read cache.
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type CacheReadable interface {
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Get(ctx context.Context, key string) (string, error)
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Close() error
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}
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type CacheGetFunc func(ctx context.Context, key string) (string, error)
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// NewCacheClient init a new cache client.
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func NewCacheClient(redisClient *redis.Client, enabled bool, prefix string, log *zap.Logger) (*CacheClient, error) {
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if redisClient == nil {
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return nil, errors.New("redis client is nil")
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}
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return &CacheClient{Client: redisClient, Enabled: enabled, logger: log, Prefix: prefix}, nil
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}
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// Get get a cache value or error from a key.
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// If the cache is not enabled, the error value
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// If the cache not contain a value from a key, the error value errors.ErrNotFound is returned.
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// If exist some internal error in the cache, the error value errros.ErrInternalError is returned.
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func (c *CacheClient) Get(ctx context.Context, key string) (string, error) {
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if !c.Enabled {
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return "", ErrCacheNotEnabled
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}
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key = c.renderKey(key)
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value, err := c.Client.Get(ctx, key).Result()
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if err != nil {
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requestID := fmt.Sprintf("%v", ctx.Value("requestid"))
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if errors.Is(err, redis.Nil) {
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c.logger.Debug("key does not exist in cache",
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zap.Error(err), zap.String("key", key), zap.String("requestID", requestID))
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return "", ErrNotFound
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}
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c.logger.Error("error getting key from cache",
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zap.Error(err), zap.String("key", key), zap.String("requestID", requestID))
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return "", ErrInternal
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}
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return value, nil
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}
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// Close close the cache client.
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func (c *CacheClient) Close() error {
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return c.Client.Close()
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}
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// Set set a value in cache.
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func (c *CacheClient) Set(ctx context.Context, key string, value interface{}, expiration time.Duration) error {
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if !c.Enabled {
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return ErrCacheNotEnabled
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}
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key = c.renderKey(key)
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err := c.Client.Set(ctx, key, value, expiration).Err()
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if err != nil {
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requestID := fmt.Sprintf("%v", ctx.Value("requestid"))
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c.logger.Error("can not set key/value in cache",
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zap.Error(err),
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zap.String("key", key),
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zap.Any("value", value),
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zap.String("requestID", requestID))
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return err
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}
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return nil
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}
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func (c *CacheClient) renderKey(key string) string {
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if c.Prefix != "" {
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return fmt.Sprintf("%s:%s", c.Prefix, key)
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}
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return key
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}
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