zones: add initial m/ scanner

Signed-off-by: Alejandro Mery <amery@jpi.io>

pkg/zones/machine.go

@@ -0,0 +1,40 @@
+package zones
+
+import (
+	"strconv"
+	"sync"
+)
+
+// A Machine is a machine on a Zone
+type Machine struct {
+	mu sync.Mutex
+
+	zone *Zone
+	id   int
+	Name string
+}
+
+func (m *Machine) String() string {
+	return m.Name
+}
+
+// ID return the index within the [Zone] associated to this [Machine]
+func (m *Machine) ID() int {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	if m.id == 0 {
+		zoneName := m.zone.Name
+
+		s := m.Name[len(zoneName)+1:]
+
+		id, err := strconv.ParseInt(s, 10, 8)
+		if err != nil {
+			panic(err)
+		}
+
+		m.id = int(id)
+	}
+
+	return m.id
+}

pkg/zones/scan.go

@@ -0,0 +1,51 @@
+package zones
+
+import (
+	"io/fs"
+)
+
+func (m *Zones) scan() error {
+	// each directory is a zone
+	entries, err := fs.ReadDir(m.dir, ".")
+	if err != nil {
+		return err
+	}
+
+	for _, e := range entries {
+		if e.IsDir() {
+			z := &Zone{
+				zones: m,
+				Name:  e.Name(),
+			}
+
+			if err := z.scan(); err != nil {
+				return err
+			}
+
+			m.Zones = append(m.Zones, z)
+		}
+	}
+
+	return nil
+}
+
+func (z *Zone) scan() error {
+	// each directory is a machine
+	entries, err := fs.ReadDir(z.zones.dir, z.Name)
+	if err != nil {
+		return err
+	}
+
+	for _, e := range entries {
+		if e.IsDir() {
+			m := &Machine{
+				zone: z,
+				Name: e.Name(),
+			}
+
+			z.Machines = append(z.Machines, m)
+		}
+	}
+
+	return nil
+}

pkg/zones/zones.go

@@ -0,0 +1,46 @@
+// Package zones contains information about the cluster
+package zones
+
+import (
+	"io/fs"
+	"os"
+)
+
+// Zone represents one zone in a cluster
+type Zone struct {
+	zones *Zones
+
+	ID   int
+	Name string
+
+	Machines []*Machine `toml:"machines"`
+}
+
+func (z *Zone) String() string {
+	return z.Name
+}
+
+// Zones represents all zones in a cluster
+type Zones struct {
+	dir fs.FS
+
+	Zones []*Zone `toml:"zones"`
+}
+
+// NewFS builds a [Zones] tree using the given directory
+func NewFS(dir fs.FS) (*Zones, error) {
+	z := &Zones{
+		dir: dir,
+	}
+
+	if err := z.scan(); err != nil {
+		return nil, err
+	}
+
+	return z, nil
+}
+
+// New builds a [Zones] tree using the given directory
+func New(dir string) (*Zones, error) {
+	return NewFS(os.DirFS(dir))
+}