initial commit

pkg/cache/cache.go

@@ -0,0 +1,129 @@
+package cache
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/samber/lo"
+
+	"base/pkg/store"
+)
+
+type Cache[V any] interface {
+	WithCache(ctx context.Context, key string, fn func(context.Context) (V, error), ttl time.Duration) (V, error)
+	WithHashCache(ctx context.Context, set string, key []string, fn func(context.Context, []string) (map[string]V, error), ttl time.Duration) (map[string]V, error)
+	InvalidateKeys(ctx context.Context, keys ...string) error
+	InvalidatePattern(ctx context.Context, pattern string) error
+}
+
+type cache[V any] struct {
+	store.Store[V]
+}
+
+func New[V any](store store.Store[V]) Cache[V] {
+	return cache[V]{store}
+}
+
+func (c cache[V]) WithCache(ctx context.Context, key string, fn func(context.Context) (V, error), ttl time.Duration) (V, error) {
+	result, found, err := c.Get(ctx, key)
+	if err != nil {
+		return result, err
+	}
+
+	if found {
+		return result, nil
+	}
+
+	result, err = fn(ctx)
+	if err != nil {
+		return result, err
+	}
+
+	err = c.Set(ctx, key, result, ttl)
+	if err != nil {
+		return result, err
+	}
+
+	return result, nil
+}
+
+func (c cache[V]) WithHashCache(ctx context.Context, set string, keys []string, fn func(context.Context, []string) (map[string]V, error), ttl time.Duration) (map[string]V, error) {
+	fetchResult := make(map[string]V, len(keys))
+	var missKeys []string
+	var getError error
+
+	// step 1 try to get from redis and figure out missedKeys
+	// for when there are no keys ignore cache retrieve all from source
+	if len(keys) > 0 {
+		fetchResult, missKeys, getError = c.get(ctx, set, keys)
+		if getError != nil {
+			return nil, getError
+		}
+
+		// all target key founded
+		if len(missKeys) == 0 {
+			return fetchResult, nil
+		}
+	}
+
+	//fetch missedKeys from source
+	newResult, fnErr := fn(ctx, missKeys)
+	if fnErr != nil {
+		return nil, fnErr
+	}
+
+	// append new result to fetchResult
+	for key, val := range newResult {
+		fetchResult[key] = val
+	}
+
+	// set new founded keys
+	setErr := c.HMSet(ctx, set, newResult, ttl)
+	if setErr != nil {
+		return nil, setErr
+	}
+
+	return fetchResult, nil
+}
+
+func (c cache[V]) get(ctx context.Context, setKey string, keys []string) (map[string]V, []string, error) {
+	fetchResult, fetchErr := c.HMGet(ctx, setKey, keys...)
+	if fetchErr != nil {
+		return nil, nil, fetchErr
+	}
+
+	if len(fetchResult) == len(keys) {
+		return fetchResult, nil, nil
+	}
+
+	if len(fetchResult) == 0 {
+		// just for avoid nil panic in higher layer
+		fetchResult = make(map[string]V, len(keys))
+	}
+
+	// found miss key for fetch from source in higher level
+	missKeys := lo.Filter(keys, func(item string, index int) bool { return !lo.HasKey(fetchResult, item) })
+
+	return fetchResult, missKeys, nil
+}
+
+func (c cache[V]) InvalidateKeys(ctx context.Context, keys ...string) error {
+	if len(keys) == 0 {
+		return nil
+	}
+
+	if err := c.Store.DeleteMultiple(ctx, keys...); err != nil {
+		return fmt.Errorf("failed to invalidate keys: %w", err)
+	}
+
+	return nil
+}
+
+func (c cache[V]) InvalidatePattern(ctx context.Context, pattern string) error {
+	if err := c.Store.Delete(ctx, pattern); err != nil {
+		return fmt.Errorf("failed to invalidate pattern: %w", err)
+	}
+
+	return nil
+}