* clients: Upstreams cache: refactor

don't use a separate container

home/clients.go

@@ -37,6 +37,11 @@ type Client struct {
 	BlockedServices       []string
 
 	Upstreams []string // list of upstream servers to be used for the client's requests
+	// Upstream objects:
+	// nil: not yet initialized
+	// not nil, but empty: initialized, no good upstreams
+	// not nil, not empty: Upstreams ready to be used
+	upstreamObjects []upstream.Upstream
 }
 
 type clientSource uint
@@ -62,11 +67,6 @@ type clientsContainer struct {
 	list    map[string]*Client     // name -> client
 	idIndex map[string]*Client     // IP -> client
 	ipHost  map[string]*ClientHost // IP -> Hostname
-
-	// cache for Upstream instances that are used in the case
-	// when custom DNS servers are configured for a client
-	upstreamsCache map[string][]upstream.Upstream // name -> []Upstream
-
 	lock    sync.Mutex
 
 	// dhcpServer is used for looking up clients IP addresses by MAC addresses
@@ -84,7 +84,6 @@ func (clients *clientsContainer) Init(objects []clientObject, dhcpServer *dhcpd.
 	clients.list = make(map[string]*Client)
 	clients.idIndex = make(map[string]*Client)
 	clients.ipHost = make(map[string]*ClientHost)
-	clients.upstreamsCache = make(map[string][]upstream.Upstream)
 	clients.dhcpServer = dhcpServer
 	clients.addFromConfig(objects)
 
@@ -198,6 +197,12 @@ func (clients *clientsContainer) Find(ip string) (Client, bool) {
 	return clients.findByIP(ip)
 }
 
+func upstreamArrayCopy(a []upstream.Upstream) []upstream.Upstream {
+	a2 := make([]upstream.Upstream, len(a))
+	copy(a2, a)
+	return a2
+}
+
 // FindUpstreams looks for upstreams configured for the client
 // If no client found for this IP, or if no custom upstreams are configured,
 // this method returns nil
@@ -210,31 +215,22 @@ func (clients *clientsContainer) FindUpstreams(ip string) []upstream.Upstream {
 		return nil
 	}
 
-	if len(c.Upstreams) == 0 {
+	if c.upstreamObjects == nil {
-		return nil
+		c.upstreamObjects = make([]upstream.Upstream, 0)
-	}
-
-	upstreams, ok := clients.upstreamsCache[c.Name]
-	if ok {
-		return upstreams
-	}
-
 		for _, us := range c.Upstreams {
 			u, err := upstream.AddressToUpstream(us, upstream.Options{Timeout: dnsforward.DefaultTimeout})
 			if err != nil {
 				log.Error("upstream.AddressToUpstream: %s: %s", us, err)
 				continue
 			}
-		upstreams = append(upstreams, u)
+			c.upstreamObjects = append(c.upstreamObjects, u)
+		}
 	}
 
-	if len(upstreams) == 0 {
+	if len(c.upstreamObjects) == 0 {
-		clients.upstreamsCache[c.Name] = nil
+		return nil
-	} else {
-		clients.upstreamsCache[c.Name] = upstreams
 	}
-
+	return upstreamArrayCopy(c.upstreamObjects)
-	return upstreams
 }
 
 // Find searches for a client by IP (and does not lock anything)
@@ -390,9 +386,6 @@ func (clients *clientsContainer) Del(name string) bool {
 	// update Name index
 	delete(clients.list, name)
 
-	// update upstreams cache
-	delete(clients.upstreamsCache, name)
-
 	// update ID index
 	for _, id := range c.IDs {
 		delete(clients.idIndex, id)
@@ -461,11 +454,7 @@ func (clients *clientsContainer) Update(name string, c Client) error {
 	}
 
 	// update upstreams cache
-	if old.Name != c.Name {
+	c.upstreamObjects = nil
-		delete(clients.upstreamsCache, old.Name)
-	} else {
-		delete(clients.upstreamsCache, c.Name)
-	}
 
 	*old = c
 	return nil