quotas: corrections to Resources.Add and quota apply parsing logic (#23894)

.changelog/23894.txt

@@ -0,0 +1,3 @@
+```release-note:improvement
+quotas (Enterprise): Added the possibility to set device count limits
+```

command/quota_apply.go

@@ -300,7 +300,15 @@ func parseQuotaResource(result *api.Resources, list *ast.ObjectList) error {
 }
 
 func parseDeviceResource(result *[]*api.RequestedDevice, list *ast.ObjectList) error {
-	for _, o := range list.Elem().Items {
+	for idx, o := range list.Items {
+		if l := len(o.Keys); l == 0 {
+			return multierror.Prefix(fmt.Errorf("missing device name"), fmt.Sprintf("resources, device[%d]->", idx))
+		} else if l > 1 {
+			return multierror.Prefix(fmt.Errorf("only one name may be specified"), fmt.Sprintf("resources, device[%d]->", idx))
+		}
+
+		name := o.Keys[0].Token.Value().(string)
+
 		// Check for invalid keys
 		valid := []string{
 			"name",
@@ -310,12 +318,15 @@ func parseDeviceResource(result *[]*api.RequestedDevice, list *ast.ObjectList) e
 			return err
 		}
 
+		// Set the name
+		var device api.RequestedDevice
+		device.Name = name
+
 		var m map[string]interface{}
 		if err := hcl.DecodeObject(&m, o.Val); err != nil {
 			return err
 		}
 
-		var device api.RequestedDevice
 		if err := mapstructure.WeakDecode(m, &device); err != nil {
 			return err
 		}

command/quota_init.go

@@ -124,7 +124,7 @@ limit {
     memory     = 1000
     memory_max = 1000
     device "nvidia/gpu/1080ti" {
-      count = 1,
+      count = 1
     }
   }
   variables_limit = 1000

nomad/structs/structs.go

@@ -2713,6 +2713,21 @@ func (r *Resources) Add(delta *Resources) {
 			r.Networks[idx].Add(n)
 		}
 	}
+
+	if r.Devices == nil && delta.Devices != nil {
+		r.Devices = make(ResourceDevices, 0)
+	}
+	for _, dd := range delta.Devices {
+		idx := slices.IndexFunc(r.Devices, func(d *RequestedDevice) bool { return d.Name == dd.Name })
+
+		// means it's not found
+		if idx < 0 {
+			r.Devices = append(r.Devices, dd)
+			continue
+		}
+
+		r.Devices[idx].Count += dd.Count
+	}
 }
 
 // GoString returns the string representation of the Resources struct.

nomad/structs/structs_test.go

@@ -3821,6 +3821,12 @@ func TestResource_Add(t *testing.T) {
 				ReservedPorts: []Port{{"web", 80, 0, ""}},
 			},
 		},
+		Devices: []*RequestedDevice{
+			{
+				Name:  "nvidia/gpu/Tesla M60",
+				Count: 1,
+			},
+		},
 	}
 
 	r1.Add(r2)
@@ -3838,6 +3844,12 @@ func TestResource_Add(t *testing.T) {
 				ReservedPorts: []Port{{"ssh", 22, 0, ""}, {"web", 80, 0, ""}},
 			},
 		},
+		Devices: []*RequestedDevice{
+			{
+				Name:  "nvidia/gpu/Tesla M60",
+				Count: 1,
+			},
+		},
 	}
 
 	must.Eq(t, expect, r1)