refactor: 'service run' create missing volumes satisfying all placement constraints

pkg/client/deploy/scheduler/volume.go

@@ -11,7 +11,7 @@ import (
 )
 
 // VolumeScheduler determines what missing volumes should be created and where for a multi-service deployment.
-// It must satisfy the following constraints:
+// It satisfies the following constraints:
 //   - Services that share a volume must be placed on the same machine where the volume is located.
 //     If the volume is located on multiple machines, services can be placed on any of them.
 //   - Services must respect their individual placement constraints.
@@ -25,6 +25,7 @@ type VolumeScheduler struct {
 	// volumeSpecs is a map of volume names to their specifications from the service specs in a canonical form.
 	volumeSpecs map[string]api.VolumeSpec
 	// volumeServices is a map of volume names to the list of service names that use the volume.
+	// TODO: not all service spec may contain the service name, so use a slice of int indexes instead of names.
 	volumeServices map[string][]string
 	// existingVolumeMachines is a map of volume names to the set of machine IDs where those volumes are located.
 	// Contains only volumes that are used by at least one service in serviceSpecs.

pkg/client/service.go

@@ -9,8 +9,10 @@ import (
 	"sync"
 
 	"github.com/docker/docker/api/types/container"
+	"github.com/docker/docker/api/types/volume"
 	"github.com/psviderski/uncloud/internal/machine/api/pb"
 	"github.com/psviderski/uncloud/pkg/api"
+	"github.com/psviderski/uncloud/pkg/client/deploy/scheduler"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/status"
@@ -39,6 +41,33 @@ func (cli *Client) RunService(ctx context.Context, spec api.ServiceSpec) (RunSer
 		}
 	}
 
+	// Create missing named Docker volumes for the service.
+	if len(spec.MountedDockerVolumes()) > 0 {
+		volumeScheduler, err := scheduler.NewVolumeSchedulerWithClient(ctx, cli, []api.ServiceSpec{spec})
+		if err != nil {
+			return resp, fmt.Errorf("init volume scheduler: %w", err)
+		}
+
+		scheduledVolumes, err := volumeScheduler.Schedule()
+		if err != nil {
+			return resp, fmt.Errorf("schedule volumes: %w", err)
+		}
+
+		// Create the missing volumes on the scheduled machines.
+		for machineID, volumes := range scheduledVolumes {
+			for _, v := range volumes {
+				_, err = cli.CreateVolume(ctx, machineID, volume.CreateOptions{
+					Name:       v.Name,
+					Driver:     v.VolumeOptions.Driver.Name,
+					DriverOpts: v.VolumeOptions.Driver.Options,
+				})
+				if err != nil {
+					return resp, fmt.Errorf("create volume '%s': %w", v.Name, err)
+				}
+			}
+		}
+	}
+
 	deployment := cli.NewDeployment(spec, nil)
 	plan, err := deployment.Run(ctx)
 	if err != nil {