Do not display scaling buttons if scaling is not possible. (#441)

* Do not display scaling buttons if scaling is not possible.

Author: Lars Maier

CHANGELOG.md

@@ -1,5 +1,7 @@
 # Change Log
 
+- Disable scaling buttons if scaling is not possible.
+
 ## [0.3.16](https://github.com/arangodb/kube-arangodb/tree/0.3.16) (2019-09-25)
 - Revised helm charts.
 - Use separate service account for operator.

pkg/deployment/cluster_scaling_integration.go

@@ -204,16 +204,32 @@ func (ci *clusterScalingIntegration) updateClusterServerCount(ctx context.Contex
 	if err != nil {
 		return false, maskAny(err)
 	}
+
+	var coordinatorCountPtr *int
+	var dbserverCountPtr *int
+
 	coordinatorCount := spec.Coordinators.GetCount()
 	dbserverCount := spec.DBServers.GetCount()
 
+	if spec.Coordinators.GetMaxCount() == spec.Coordinators.GetMinCount() {
+		coordinatorCountPtr = nil
+	} else {
+		coordinatorCountPtr = &coordinatorCount
+	}
+
+	if spec.DBServers.GetMaxCount() == spec.DBServers.GetMinCount() {
+		dbserverCountPtr = nil
+	} else {
+		dbserverCountPtr = &dbserverCount
+	}
+
 	ci.lastNumberOfServers.mutex.Lock()
 	lastNumberOfServers := ci.lastNumberOfServers.NumberOfServers
 	ci.lastNumberOfServers.mutex.Unlock()
 
 	// This is to prevent unneseccary updates that may override some values written by the WebUI (in the case of a update loop)
 	if coordinatorCount != lastNumberOfServers.GetCoordinators() || dbserverCount != lastNumberOfServers.GetDBServers() {
-		if err := arangod.SetNumberOfServers(ctx, c.Connection(), coordinatorCount, dbserverCount); err != nil {
+		if err := arangod.SetNumberOfServers(ctx, c.Connection(), coordinatorCountPtr, dbserverCountPtr); err != nil {
 			if expectSuccess {
 				log.Debug().Err(err).Msg("Failed to set number of servers")
 			}

pkg/util/arangod/cluster.go

@@ -71,14 +71,14 @@ func GetNumberOfServers(ctx context.Context, conn driver.Connection) (NumberOfSe
 }
 
 // SetNumberOfServers updates the number of servers the cluster has.
-func SetNumberOfServers(ctx context.Context, conn driver.Connection, noCoordinators, noDBServers int) error {
+func SetNumberOfServers(ctx context.Context, conn driver.Connection, noCoordinators, noDBServers *int) error {
 	req, err := conn.NewRequest("PUT", "_admin/cluster/numberOfServers")
 	if err != nil {
 		return maskAny(err)
 	}
 	input := NumberOfServers{
-		Coordinators: &noCoordinators,
-		DBServers:    &noDBServers,
+		Coordinators: noCoordinators,
+		DBServers:    noDBServers,
 	}
 	if _, err := req.SetBody(input); err != nil {
 		return maskAny(err)