feat: init firecracker

internal/firecracker/spec.go

@@ -0,0 +1,94 @@
+package firecracker
+
+import (
+	"fmt"
+	"path/filepath"
+	"strings"
+)
+
+// MachineID uniquely identifies a single microVM on a host.
+type MachineID string
+
+// MachineSpec describes the minimum machine inputs required to boot a guest.
+type MachineSpec struct {
+	ID              MachineID
+	VCPUs           int64
+	MemoryMiB       int64
+	KernelImagePath string
+	RootFSPath      string
+	KernelArgs      string
+	Drives          []DriveSpec
+	Vsock           *VsockSpec
+}
+
+// Validate reports whether the machine specification is usable for boot.
+func (s MachineSpec) Validate() error {
+	if strings.TrimSpace(string(s.ID)) == "" {
+		return fmt.Errorf("machine id is required")
+	}
+	if s.VCPUs < 1 {
+		return fmt.Errorf("machine vcpus must be at least 1")
+	}
+	if s.MemoryMiB < 1 {
+		return fmt.Errorf("machine memory must be at least 1 MiB")
+	}
+	if strings.TrimSpace(s.KernelImagePath) == "" {
+		return fmt.Errorf("machine kernel image path is required")
+	}
+	if strings.TrimSpace(s.RootFSPath) == "" {
+		return fmt.Errorf("machine rootfs path is required")
+	}
+	if filepath.Base(strings.TrimSpace(string(s.ID))) != strings.TrimSpace(string(s.ID)) {
+		return fmt.Errorf("machine id %q must not contain path separators", s.ID)
+	}
+	for i, drive := range s.Drives {
+		if err := drive.Validate(); err != nil {
+			return fmt.Errorf("drive %d: %w", i, err)
+		}
+	}
+	if s.Vsock != nil {
+		if err := s.Vsock.Validate(); err != nil {
+			return fmt.Errorf("vsock: %w", err)
+		}
+	}
+	return nil
+}
+
+// DriveSpec describes an additional guest block device.
+type DriveSpec struct {
+	ID       string
+	Path     string
+	ReadOnly bool
+}
+
+// Validate reports whether the drive specification is usable.
+func (d DriveSpec) Validate() error {
+	if strings.TrimSpace(d.ID) == "" {
+		return fmt.Errorf("drive id is required")
+	}
+	if strings.TrimSpace(d.Path) == "" {
+		return fmt.Errorf("drive path is required")
+	}
+	return nil
+}
+
+// VsockSpec describes a single host-guest vsock device.
+type VsockSpec struct {
+	ID   string
+	CID  uint32
+	Path string
+}
+
+// Validate reports whether the vsock specification is usable.
+func (v VsockSpec) Validate() error {
+	if strings.TrimSpace(v.ID) == "" {
+		return fmt.Errorf("vsock id is required")
+	}
+	if v.CID == 0 {
+		return fmt.Errorf("vsock cid must be non-zero")
+	}
+	if strings.TrimSpace(v.Path) == "" {
+		return fmt.Errorf("vsock path is required")
+	}
+	return nil
+}