cluster: NewFromConfig() trying JSON and YAML

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

pkg/cluster/cluster_import.go

@@ -0,0 +1,137 @@
+package cluster
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+
+	"gopkg.in/yaml.v3"
+)
+
+func (m *Cluster) init(opts *ScanOptions) error {
+	for _, fn := range []func(*ScanOptions) error{
+		m.initZones,
+		m.scanZoneIDs,
+		m.scanSort,
+		m.scanGateways,
+	} {
+		if err := fn(opts); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (m *Cluster) initZones(opts *ScanOptions) error {
+	var err error
+
+	sub, err := DirFS(m.BaseDir)
+	if err != nil {
+		return err
+	}
+
+	m.dir = sub
+
+	m.ForEachZone(func(z *Zone) bool {
+		err = m.initZone(z, opts)
+		return err != nil
+	})
+
+	return err
+}
+
+func (m *Cluster) initZone(z *Zone, _ *ScanOptions) error {
+	var hasMissing bool
+	var lastMachineID int
+
+	z.zones = m
+	z.logger = m
+
+	z.ForEachMachine(func(p *Machine) bool {
+		p.zone = z
+		p.logger = z
+
+		switch {
+		case p.ID == 0:
+			hasMissing = true
+		case p.ID > lastMachineID:
+			lastMachineID = z.ID
+		}
+
+		return false
+	})
+
+	if hasMissing {
+		next := lastMachineID + 1
+
+		z.ForEachMachine(func(p *Machine) bool {
+			if p.ID == 0 {
+				p.ID, next = next, next+1
+			}
+
+			return false
+		})
+	}
+
+	z.ForEachMachine(func(p *Machine) bool {
+		p.Name = fmt.Sprintf("%s-%v", z.Name, p.ID)
+		return false
+	})
+
+	return nil
+}
+
+func decodeConfigData(data []byte) (out *Cluster, err error) {
+	// try JSON first
+	out = new(Cluster)
+	err = json.Unmarshal(data, out)
+	if err == nil {
+		// good json
+		return out, nil
+	} else if _, ok := err.(*json.SyntaxError); !ok {
+		// bad json
+		return nil, err
+	}
+
+	out = new(Cluster)
+	err = yaml.Unmarshal(data, out)
+	if err != nil {
+		// bad yaml too
+		return nil, err
+	}
+
+	// good yaml
+	return out, nil
+}
+
+// NewFromConfig loads the cluster data from the given file
+func NewFromConfig(filename string, opts ...ScanOption) (*Cluster, error) {
+	var scanOptions ScanOptions
+
+	data, err := os.ReadFile(filename)
+	if err != nil {
+		return nil, err
+	}
+
+	m, err := decodeConfigData(data)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, opt := range opts {
+		if err = opt(m, &scanOptions); err != nil {
+			return nil, err
+		}
+	}
+
+	if err = m.setScanDefaults(&scanOptions); err != nil {
+		return nil, err
+	}
+
+	if err := m.init(&scanOptions); err != nil {
+		return nil, err
+	}
+
+	return m, nil
+}