chore: init scheduler entities

pkg/client/deploy/scheduler/constraint.go

@@ -0,0 +1,37 @@
+package scheduler
+
+import (
+	"strings"
+
+	"github.com/psviderski/uncloud/pkg/api"
+)
+
+// Constraint is the base interface for all scheduling constraints.
+type Constraint interface {
+	// Evaluate determines if a machine satisfies the constraint.
+	Evaluate(machine *Machine) bool
+
+	// Description returns a human-readable description of the constraint.
+	Description() string
+}
+
+func constraintsFromSpec(spec api.ServiceSpec) []Constraint {
+	return []Constraint{}
+}
+
+type PlacementConstraint struct {
+	Machines []string
+}
+
+func (c *PlacementConstraint) Evaluate(machine *Machine) bool {
+	for _, nameOrID := range c.Machines {
+		if machine.Info.Id == nameOrID || machine.Info.Name == nameOrID {
+			return true
+		}
+	}
+	return false
+}
+
+func (c *PlacementConstraint) Description() string {
+	return "Placement constraint by machines: " + strings.Join(c.Machines, ", ")
+}