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cache.go
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cache.go
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package client
import (
"sort"
"strings"
lru "github.com/hashicorp/golang-lru"
)
type ProviderCache struct {
provider promClientProvider
cache *lru.Cache
}
type promClientProvider interface {
GetClient(map[string]string) (*Client, error)
}
func NewProviderCache(p promClientProvider) (*ProviderCache, error) {
cache, err := lru.New(500)
if err != nil {
return nil, err
}
return &ProviderCache{
provider: p,
cache: cache,
}, nil
}
func (c *ProviderCache) GetClient(headers map[string]string) (*Client, error) {
key := c.key(headers)
if client, ok := c.cache.Get(key); ok {
return client.(*Client), nil
}
client, err := c.provider.GetClient(headers)
if err != nil {
return nil, err
}
c.cache.Add(key, client)
return client, nil
}
func (c *ProviderCache) key(headers map[string]string) string {
vals := make([]string, len(headers))
var i int
for _, v := range headers {
vals[i] = v
i++
}
sort.Strings(vals)
return strings.Join(vals, "")
}