Use hash/fnv, add tests, fix request bug

client/cache.go

@@ -2,63 +2,52 @@ package client
 
 import (
 	"context"
-	"crypto/sha1"
 	"encoding/json"
 	"fmt"
-	"sync"
+	"hash/fnv"
 	"time"
 
 	"github.com/micro/go-micro/v2/metadata"
+	cache "github.com/patrickmn/go-cache"
 )
 
 // NewCache returns an initialised cache.
-// TODO: Setup a go routine to expire records in the cache.
 func NewCache() *Cache {
 	return &Cache{
-		values: make(map[string]interface{}),
+		cache: cache.New(cache.NoExpiration, 30*time.Second),
 	}
 }
 
 // Cache for responses
 type Cache struct {
-	values map[string]interface{}
-	mutex  sync.Mutex
+	cache *cache.Cache
 }
 
 // Get a response from the cache
-func (c *Cache) Get(ctx context.Context, req *Request) interface{} {
-	md, _ := metadata.FromContext(ctx)
-	ck := cacheKey{req, md}
-
-	c.mutex.Lock()
-	defer c.mutex.Unlock()
-
-	if val, ok := c.values[ck.Hash()]; ok {
-		return val
-	}
-
-	return nil
+func (c *Cache) Get(ctx context.Context, req *Request) (interface{}, bool) {
+	return c.cache.Get(key(ctx, req))
 }
 
 // Set a response in the cache
 func (c *Cache) Set(ctx context.Context, req *Request, rsp interface{}, expiry time.Duration) {
+	c.cache.Set(key(ctx, req), rsp, expiry)
+}
+
+// key returns a hash for the context and request
+func key(ctx context.Context, req *Request) string {
 	md, _ := metadata.FromContext(ctx)
-	ck := cacheKey{req, md}
 
-	c.mutex.Lock()
-	c.values[ck.Hash()] = rsp
-	defer c.mutex.Unlock()
-}
+	bytes, _ := json.Marshal(map[string]interface{}{
+		"metadata": md,
+		"request": map[string]interface{}{
+			"service":  (*req).Service(),
+			"endpoint": (*req).Endpoint(),
+			"method":   (*req).Method(),
+			"body":     (*req).Body(),
+		},
+	})
 
-type cacheKey struct {
-	Request  *Request
-	Metadata metadata.Metadata
-}
-
-// Source: https://gobyexample.com/sha1-hashes
-func (k *cacheKey) Hash() string {
-	bytes, _ := json.Marshal(k)
-	h := sha1.New()
+	h := fnv.New64()
 	h.Write(bytes)
 	return fmt.Sprintf("%x", h.Sum(nil))
 }