[#184] Add SDK client cache package

With this package we can reuse already created connections.
Later on neofs-api-go will support checking connection health
and `Close` operation, so this cache could run worker and remove
unhealthy clients.

Signed-off-by: Alex Vanin <alexey@nspcc.ru>
This commit is contained in:
Alex Vanin 2020-11-18 16:01:59 +03:00 committed by Alex Vanin
parent b8d66bf202
commit fb90827532

69
pkg/network/cache/client.go vendored Normal file
View file

@ -0,0 +1,69 @@
package cache
import (
"crypto/ecdsa"
"crypto/sha256"
"encoding/hex"
"sync"
"github.com/nspcc-dev/neofs-api-go/pkg/client"
crypto "github.com/nspcc-dev/neofs-crypto"
)
type (
// ClientCache is a structure around neofs-api-go/pkg/client to reuse
// already created clients.
ClientCache struct {
mu *sync.RWMutex
clients map[string]*client.Client
}
)
// NewSDKClientCache creates instance of client cache.
func NewSDKClientCache() *ClientCache {
return &ClientCache{
mu: new(sync.RWMutex),
clients: make(map[string]*client.Client),
}
}
// Get function returns existing client or creates a new one. Consider passing
// connection options to specify details for client, but don't forget that two
// different set of options should provide two different clients.
func (c *ClientCache) Get(key *ecdsa.PrivateKey, address string) (*client.Client, error) {
id := uniqueID(key, address)
c.mu.RLock()
if cli, ok := c.clients[id]; ok {
// todo: check underlying connection neofs-api-go#196
c.mu.RUnlock()
return cli, nil
}
c.mu.RUnlock()
// if client is not found in cache, then create a new one
c.mu.Lock()
defer c.mu.Unlock()
// check once again if client is missing in cache, concurrent routine could
// create client while this routine was locked on `c.mu.Lock()`.
if cli, ok := c.clients[id]; ok {
return cli, nil
}
cli, err := client.New(key, client.WithAddress(address))
if err != nil {
return nil, err
}
c.clients[id] = cli
return cli, nil
}
func uniqueID(key *ecdsa.PrivateKey, address string) string {
keyFingerprint := sha256.Sum256(crypto.MarshalPrivateKey(key))
return hex.EncodeToString(keyFingerprint[:]) + address
}