Add node class to constraints

scheduler/feasible.go

@@ -335,6 +335,9 @@ func resolveConstraintTarget(target string, node *structs.Node) (interface{}, bo
 	case "$node.name" == target:
 		return node.Name, true
 
+	case "$node.class" == target:
+		return node.NodeClass, true
+
 	case strings.HasPrefix(target, "$attr."):
 		attr := strings.TrimPrefix(target, "$attr.")
 		val, ok := node.Attributes[attr]

scheduler/feasible_test.go

@@ -112,11 +112,13 @@ func TestConstraintIterator(t *testing.T) {
 		mock.Node(),
 		mock.Node(),
 		mock.Node(),
+		mock.Node(),
 	}
 	static := NewStaticIterator(ctx, nodes)
 
 	nodes[0].Attributes["kernel.name"] = "freebsd"
 	nodes[1].Datacenter = "dc2"
+	nodes[2].NodeClass = "large"
 
 	constraints := []*structs.Constraint{
 		&structs.Constraint{
@@ -129,6 +131,11 @@ func TestConstraintIterator(t *testing.T) {
 			LTarget: "$attr.kernel.name",
 			RTarget: "linux",
 		},
+		&structs.Constraint{
+			Operand: "is",
+			LTarget: "$node.class",
+			RTarget: "large",
+		},
 	}
 	constr := NewConstraintIterator(ctx, static, constraints)
 
@@ -168,6 +175,12 @@ func TestResolveConstraintTarget(t *testing.T) {
 			val:    node.Name,
 			result: true,
 		},
+		{
+			target: "$node.class",
+			node:   node,
+			val:    node.NodeClass,
+			result: true,
+		},
 		{
 			target: "$node.foo",
 			node:   node,

website/source/docs/jobspec/index.html.md

@@ -339,6 +339,10 @@ Below is a table documenting the variables that can be interpreted:
     <td>$node.name</td>
     <td>The client node name</td>
   </tr>
+  <tr>
+    <td>$node.class</td>
+    <td>The client node class</td>
+  </tr>
   <tr>
     <td>$attr.\<key\></td>
     <td>The attribute given by `key` on the client node.</td>