Merge pull request #1143 from mholt/1136-fix

Fix #1136 - IP hash policy no longer changes host pool

caddyhttp/proxy/policy.go

@@ -121,18 +121,13 @@ func (r *IPHash) Select(pool HostPool, request *http.Request) *UpstreamHost {
 	if err != nil {
 		clientIP = request.RemoteAddr
 	}
-	hash := hash(clientIP)
-	for {
-		if poolLen == 0 {
-			break
-		}
-		index := hash % poolLen
-		host := pool[index]
+	index := hash(clientIP) % poolLen
+	for i := uint32(0); i < poolLen; i++ {
+		index += i
+		host := pool[index%poolLen]
 		if host.Available() {
 			return host
 		}
-		pool = append(pool[:index], pool[index+1:]...)
-		poolLen--
 	}
 	return nil
 }

caddyhttp/proxy/policy_test.go

@@ -163,14 +163,14 @@ func TestIPHashPolicy(t *testing.T) {
 	request.RemoteAddr = "172.0.0.1"
 	pool[1].Unhealthy = true
 	h = ipHash.Select(pool, request)
-	if h != pool[0] {
-		t.Error("Expected ip hash policy host to be the first host.")
+	if h != pool[2] {
+		t.Error("Expected ip hash policy host to be the third host.")
 	}
 
 	request.RemoteAddr = "172.0.0.2"
 	h = ipHash.Select(pool, request)
-	if h != pool[1] {
-		t.Error("Expected ip hash policy host to be the second host.")
+	if h != pool[2] {
+		t.Error("Expected ip hash policy host to be the third host.")
 	}
 	pool[1].Unhealthy = false
 
@@ -182,8 +182,8 @@ func TestIPHashPolicy(t *testing.T) {
 	}
 	request.RemoteAddr = "172.0.0.4"
 	h = ipHash.Select(pool, request)
-	if h != pool[0] {
-		t.Error("Expected ip hash policy host to be the first host.")
+	if h != pool[1] {
+		t.Error("Expected ip hash policy host to be the second host.")
 	}
 
 	// We should be able to resize the host pool and still be able to predict