Fix up review feedback

azurerm/resource_arm_container_group.go

@@ -309,8 +309,8 @@ func resourceArmContainerGroupRead(d *schema.ResourceData, meta interface{}) err
 	}
 	flattenAndSetTags(d, resp.Tags)
 
-	if imageRegCreds := flattenContainerImageRegistryCredentials(d, resp.ImageRegistryCredentials); imageRegCreds != nil {
-		d.Set("image_registry_credential", imageRegCreds)
+	if err := d.Set("image_registry_credential", flattenContainerImageRegistryCredentials(d, resp.ImageRegistryCredentials)); err != nil {
+		return fmt.Errorf("Error setting `capabilities`: %+v", err)
 	}
 
 	d.Set("os_type", string(resp.OsType))
@@ -578,14 +578,10 @@ func expandContainerImageRegistryCredentials(d *schema.ResourceData) *[]containe
 	for _, c := range credsRaw {
 		credConfig := c.(map[string]interface{})
 
-		server := credConfig["server"].(string)
-		username := credConfig["username"].(string)
-		password := credConfig["password"].(string)
-
 		output = append(output, containerinstance.ImageRegistryCredential{
-			Server:   &server,
-			Password: &password,
-			Username: &username,
+			Server:   utils.String(credConfig["server"].(string)),
+			Password: utils.String(credConfig["password"].(string)),
+			Username: utils.String(credConfig["username"].(string)),
 		})
 	}
 
@@ -599,8 +595,13 @@ func flattenContainerImageRegistryCredentials(d *schema.ResourceData, credsPtr *
 	configsOld := d.Get("image_registry_credential").([]interface{})
 
 	creds := *credsPtr
-	output := make([]interface{}, len(creds))
+	output := make([]interface{}, 0, len(creds))
 	for _, cred := range creds {
+		// Seems some responses include empty items. Ignore these.
+		if cred.Server == nil {
+			continue
+		}
+
 		credConfig := make(map[string]interface{})
 		if cred.Server != nil {
 			credConfig["server"] = *cred.Server
@@ -610,6 +611,9 @@ func flattenContainerImageRegistryCredentials(d *schema.ResourceData, credsPtr *
 		}
 
 		for i, configsOld := range configsOld {
+			if configsOld == nil {
+				continue
+			}
 			data := configsOld.(map[string]interface{})
 			oldServer := data["server"].(string)
 			if cred.Server != nil && *cred.Server == oldServer {

azurerm/resource_arm_container_group_test.go

@@ -223,7 +223,7 @@ resource "azurerm_container_group" "test" {
     image  = "microsoft/aci-helloworld:latest"
     cpu    = "0.5"
     memory = "0.5"
-	port   = "80"
+	  port   = "80"
   }
   
   image_registry_credential {

examples/aci-image-registry-credentials/main.tf

@@ -16,6 +16,12 @@ resource "azurerm_container_group" "aci-test" {
     password = "yourpassword"
   }
 
+  image_registry_credential {
+    server   = "2hub.docker.com"
+    username = "2yourusername1"
+    password = "2yourpassword"
+  }
+
   container {
     name   = "hw"
     image  = "microsoft/aci-helloworld:latest"