micro/client/cache.go
2020-05-24 18:45:57 +01:00

67 lines
1.4 KiB
Go

package client
import (
"context"
"encoding/json"
"fmt"
"hash/fnv"
"time"
"github.com/micro/go-micro/v2/metadata"
cache "github.com/patrickmn/go-cache"
)
// NewCache returns an initialised cache.
func NewCache() *Cache {
return &Cache{
cache: cache.New(cache.NoExpiration, 30*time.Second),
}
}
// Cache for responses
type Cache struct {
cache *cache.Cache
}
// Get a response from the cache
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)
}
// List the key value pairs in the cache
func (c *Cache) List() map[string]string {
items := c.cache.Items()
rsp := make(map[string]string, len(items))
for k, v := range items {
bytes, _ := json.Marshal(v.Object)
rsp[k] = string(bytes)
}
return rsp
}
// key returns a hash for the context and request
func key(ctx context.Context, req *Request) string {
md, _ := metadata.FromContext(ctx)
bytes, _ := json.Marshal(map[string]interface{}{
"metadata": md,
"request": map[string]interface{}{
"service": (*req).Service(),
"endpoint": (*req).Endpoint(),
"method": (*req).Method(),
"body": (*req).Body(),
},
})
h := fnv.New64()
h.Write(bytes)
return fmt.Sprintf("%x", h.Sum(nil))
}