api: add constraints generators

api/jobs.go

@@ -82,6 +82,7 @@ type Job struct {
 	Priority          int
 	AllAtOnce         bool
 	Datacenters       []string
+	Constraints       []*Constraint
 	Meta              map[string]string
 	Status            string
 	StatusDescription string
@@ -96,3 +97,35 @@ type registerJobRequest struct {
 type registerJobResponse struct {
 	EvalID string
 }
+
+// Constraint is used to serialize a job placement constraint.
+type Constraint struct {
+	Hard    bool
+	LTarget string
+	RTarget string
+	Operand string
+	Weight  int
+}
+
+// HardConstraint is used to create a new hard constraint.
+func HardConstraint(left, operand, right string) *Constraint {
+	return constraint(left, operand, right, true, 0)
+}
+
+// SoftConstraint is used to create a new soft constraint. It
+// takes an additional weight parameter to allow balancing
+// multiple soft constraints amongst eachother.
+func SoftConstraint(left, operand, right string, weight int) *Constraint {
+	return constraint(left, operand, right, false, weight)
+}
+
+// constraint generates a new job placement constraint.
+func constraint(left, operand, right string, hard bool, weight int) *Constraint {
+	return &Constraint{
+		Hard:    hard,
+		LTarget: left,
+		RTarget: right,
+		Operand: operand,
+		Weight:  weight,
+	}
+}

api/jobs_test.go

@@ -178,3 +178,33 @@ func TestJobs_Delete(t *testing.T) {
 		t.Fatalf("expected 0 jobs, got: %d", n)
 	}
 }
+
+func TestJobs_Constraints(t *testing.T) {
+	{
+		c := HardConstraint("kernel.name", "=", "darwin")
+		expect := &Constraint{
+			Hard:    true,
+			LTarget: "kernel.name",
+			RTarget: "darwin",
+			Operand: "=",
+			Weight:  0,
+		}
+		if !reflect.DeepEqual(c, expect) {
+			t.Fatalf("expect: %#v, got: %#v", expect, c)
+		}
+	}
+
+	{
+		c := SoftConstraint("memory.totalbytes", ">=", "250000000", 5)
+		expect := &Constraint{
+			Hard:    false,
+			LTarget: "memory.totalbytes",
+			RTarget: "250000000",
+			Operand: ">=",
+			Weight:  5,
+		}
+		if !reflect.DeepEqual(c, expect) {
+			t.Fatalf("expect: %#v, got: %#v", expect, c)
+		}
+	}
+}