pkg/cluster/cluster_scan.go

@@ -2,17 +2,25 @@ package cluster
 
 import (
 	"io/fs"
+	"path"
 	"sort"
 
 	"darvaza.org/core"
 )
 
+const (
+	// ZoneRegionsFileName indicates the file containing
+	// region names as references
+	ZoneRegionsFileName = "regions"
+)
+
 func (m *Cluster) scan(opts *ScanOptions) error {
 	for _, fn := range []func(*ScanOptions) error{
 		m.scanDirectory,
 		m.scanMachines,
 		m.scanZoneIDs,
 		m.scanSort,
+		m.initRegions,
 		m.scanGateways,
 		m.scanCephMonitors,
 	} {
@@ -24,7 +32,7 @@ func (m *Cluster) scan(opts *ScanOptions) error {
 	return nil
 }
 
-func (m *Cluster) scanDirectory(_ *ScanOptions) error {
+func (m *Cluster) scanDirectory(opts *ScanOptions) error {
 	// each directory is a zone
 	entries, err := fs.ReadDir(m.dir, ".")
 	if err != nil {
@@ -33,16 +41,14 @@ func (m *Cluster) scanDirectory(_ *ScanOptions) error {
 
 	for _, e := range entries {
 		if e.IsDir() {
-			z, err := m.newZone(e.Name())
+			ok, err := m.scanSubdirectory(opts, e.Name())
 			switch {
 			case err != nil:
 				return core.Wrap(err, e.Name())
-			case z.Machines.Len() == 0:
-				z.warn(nil).
-					WithField("zone", z.Name).
+			case !ok:
+				m.warn(nil).
+					WithField("zone", e.Name()).
 					Print("empty")
-			default:
-				m.Zones = append(m.Zones, z)
 			}
 		}
 	}
@@ -50,6 +56,27 @@ func (m *Cluster) scanDirectory(_ *ScanOptions) error {
 	return nil
 }
 
+func (m *Cluster) scanSubdirectory(_ *ScanOptions, name string) (bool, error) {
+	z, err := m.newZone(name)
+	switch {
+	case err != nil:
+		// somewhere went wrong scanning the subdirectory
+		return false, err
+	case z.Machines.Len() > 0:
+		// zones have machines and the regions they belong
+		m.Zones = append(m.Zones, z)
+		return true, nil
+	case len(z.Regions) > 0:
+		// regions have no machines but can include
+		// other regions
+		m.appendRegionRegions(name, z.Regions...)
+		return true, nil
+	default:
+		// empty
+		return false, nil
+	}
+}
+
 func (m *Cluster) newZone(name string) (*Zone, error) {
 	z := &Zone{
 		zones:  m,
@@ -154,11 +181,48 @@ func (z *Zone) scan() error {
 	}
 
 	for _, e := range entries {
-		if e.IsDir() {
+		name := e.Name()
+
+		switch {
+		case name == ZoneRegionsFileName:
+			err = z.loadRegions()
+		case e.IsDir():
+			err = z.scanSubdirectory(name)
+		default:
+			z.warn(nil).
+				WithField("zone", z.Name).
+				WithField("filename", name).
+				Print("unknown")
+		}
+
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (z *Zone) loadRegions() error {
+	filename := path.Join(z.Name, ZoneRegionsFileName)
+	regions, err := z.zones.ReadLines(filename)
+
+	if err == nil {
+		// parsed
+		err = z.appendRegions(regions...)
+		if err != nil {
+			err = core.Wrap(err, filename)
+		}
+	}
+
+	return err
+}
+
+func (z *Zone) scanSubdirectory(name string) error {
 	m := &Machine{
 		zone:   z,
 		logger: z,
-				Name:   e.Name(),
+		Name:   name,
 	}
 
 	m.debug().
@@ -176,9 +240,6 @@ func (z *Zone) scan() error {
 	}
 
 	z.Machines = append(z.Machines, m)
-		}
-	}
-
 	return nil
 }
 

pkg/cluster/regions.go

@@ -1,5 +1,10 @@
 package cluster
 
+import (
+	"bytes"
+	"path/filepath"
+)
+
 var (
 	_ MachineIterator = (*Region)(nil)
 	_ ZoneIterator    = (*Region)(nil)
@@ -68,7 +73,7 @@ func (m *Cluster) initRegions(_ *ScanOptions) error {
 
 	// bind first level regions and their zones
 	for name, zones := range regions {
-		m.syncRegions(name, zones...)
+		m.setRegionZones(name, zones...)
 	}
 
 	// and combine zones to produce larger regions
@@ -81,8 +86,10 @@ func (m *Cluster) initRegions(_ *ScanOptions) error {
 	return nil
 }
 
-func (m *Cluster) syncRegions(name string, zones ...*Zone) {
-	for _, r := range m.Regions {
+func (m *Cluster) setRegionZones(name string, zones ...*Zone) {
+	for i := range m.Regions {
+		r := &m.Regions[i]
+
 		if r.Name == name {
 			// found
 			r.m = m
@@ -99,6 +106,38 @@ func (m *Cluster) syncRegions(name string, zones ...*Zone) {
 	})
 }
 
+func (m *Cluster) appendRegionRegions(name string, subs ...string) {
+	for i := range m.Regions {
+		r := &m.Regions[i]
+
+		if name == r.Name {
+			// found
+			r.Regions = append(r.Regions, subs...)
+			return
+		}
+	}
+
+	// new
+	m.Regions = append(m.Regions, Region{
+		Name:    name,
+		Regions: subs,
+	})
+}
+
+func (z *Zone) appendRegions(regions ...string) error {
+	for _, s := range regions {
+		// TODO: validate
+		z.debug().
+			WithField("zone", z.Name).
+			WithField("region", s).
+			Print("attached")
+
+		z.Regions = append(z.Regions, s)
+	}
+
+	return nil
+}
+
 func (m *Cluster) finishRegion(r *Region) {
 	if r.m != nil {
 		// ready
@@ -132,3 +171,61 @@ func (m *Cluster) getRegion(name string) (*Region, bool) {
 
 	return nil, false
 }
+
+// SyncRegions writes to the file system the regions this [Zone]
+// belongs to.
+func (z *Zone) SyncRegions() error {
+	err := z.syncZoneRegions()
+	if err == nil {
+		z.ForEachMachine(func(p *Machine) bool {
+			if p.IsActive() {
+				err = p.RemoveFile("region")
+			} else {
+				err = p.WriteStringFile("none\n", "region")
+			}
+			return err != nil
+		})
+	}
+
+	return err
+}
+
+func (z *Zone) syncZoneRegions() error {
+	name := filepath.Join(z.Name, "regions")
+
+	if len(z.Regions) > 0 {
+		var buf bytes.Buffer
+
+		for _, s := range z.Regions {
+			_, _ = buf.WriteString(s)
+			_, _ = buf.WriteRune('\n')
+		}
+
+		return z.zones.WriteStringFile(buf.String(), name)
+	}
+
+	return z.zones.RemoveFile(name)
+}
+
+// SyncRegions writes to the file system the regions covered
+// by this meta-region
+func (r *Region) SyncRegions() error {
+	name := filepath.Join(r.Name, "regions")
+
+	if len(r.Regions) > 0 {
+		var buf bytes.Buffer
+
+		for _, s := range r.Regions {
+			_, _ = buf.WriteString(s)
+			_, _ = buf.WriteRune('\n')
+		}
+
+		if err := r.m.MkdirAll(r.Name); err != nil {
+			return err
+		}
+
+		return r.m.WriteStringFile(buf.String(), name)
+	}
+
+	return r.m.RemoveFile(name)
+}

pkg/cluster/sync.go

@@ -6,6 +6,7 @@ func (m *Cluster) SyncAll() error {
 		m.SyncMkdirAll,
 		m.SyncAllWireguard,
 		m.SyncAllCeph,
+		m.SyncAllRegions,
 		m.WriteHosts,
 	} {
 		if err := fn(); err != nil {
@@ -58,3 +59,24 @@ func (m *Cluster) SyncAllCeph() error {
 
 	return m.WriteCephConfig(cfg)
 }
+
+// SyncAllRegions rewrites all region data
+func (m *Cluster) SyncAllRegions() error {
+	var err error
+
+	m.ForEachZone(func(z *Zone) bool {
+		err := z.SyncRegions()
+		return err != nil
+	})
+
+	if err != nil {
+		return err
+	}
+
+	m.ForEachRegion(func(r *Region) bool {
+		err = r.SyncRegions()
+		return err != nil
+	})
+
+	return err
+}