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, ", ")
+}

pkg/client/deploy/scheduler/machine.go

@@ -0,0 +1,50 @@
+package scheduler
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/docker/docker/api/types/volume"
+	"github.com/psviderski/uncloud/internal/machine/api/pb"
+	"github.com/psviderski/uncloud/pkg/api"
+)
+
+type Client interface {
+	api.MachineClient
+	api.VolumeClient
+}
+
+type Machine struct {
+	Info    *pb.MachineInfo
+	Volumes []volume.Volume
+}
+
+// InspectMachines retrieves the list of available machines and their details required for scheduling purposes.
+// TODO: refactor to get all the details in one broadcast call to machine API.
+func InspectMachines(ctx context.Context, cli Client) ([]*Machine, error) {
+	machineMembers, err := cli.ListMachines(ctx, &api.MachineFilter{Available: true})
+	if err != nil {
+		return nil, fmt.Errorf("list machines: %w", err)
+	}
+	volumes, err := cli.ListVolumes(ctx, nil)
+	if err != nil {
+		return nil, fmt.Errorf("list volumes: %w", err)
+	}
+
+	var machines []*Machine
+	for _, m := range machineMembers {
+		machine := &Machine{
+			Info: m.Machine,
+		}
+
+		for _, v := range volumes {
+			if v.MachineID == m.Machine.Id {
+				machine.Volumes = append(machine.Volumes, v.Volume)
+			}
+		}
+
+		machines = append(machines, machine)
+	}
+
+	return machines, nil
+}

pkg/client/deploy/scheduler/service.go

@@ -0,0 +1,51 @@
+package scheduler
+
+import (
+	"errors"
+
+	"github.com/psviderski/uncloud/internal/machine/api/pb"
+	"github.com/psviderski/uncloud/pkg/api"
+)
+
+type ServiceScheduler struct {
+	machines    []*Machine
+	spec        api.ServiceSpec
+	constraints []Constraint
+}
+
+func NewServiceScheduler(machines []*Machine, spec api.ServiceSpec, constraints []Constraint) *ServiceScheduler {
+	specConstraints := constraintsFromSpec(spec)
+	specConstraints = append(specConstraints, constraints...)
+
+	return &ServiceScheduler{
+		machines:    machines,
+		spec:        spec,
+		constraints: specConstraints,
+	}
+}
+
+func (s *ServiceScheduler) AvailableMachines() ([]*Machine, error) {
+	var available []*Machine
+	for _, machine := range s.machines {
+		if s.evaluateConstraints(machine) {
+			available = append(available, machine)
+		}
+	}
+	if len(available) == 0 {
+		return nil, errors.New("no machines available that satisfy all constraints")
+	}
+	return available, nil
+}
+
+func (s *ServiceScheduler) evaluateConstraints(machine *Machine) bool {
+	for _, c := range s.constraints {
+		if !c.Evaluate(machine) {
+			return false
+		}
+	}
+	return true
+}
+
+func (s *ServiceScheduler) ScheduleContainer() ([]*pb.MachineInfo, error) {
+	return nil, errors.New("not implemented")
+}