f-21: refactor: add dispatcher layer for MQTT migration

Introduce internal/dispatcher package with a Command interface and typed
commands (CreateVPC, DeleteVPC, CreateSubnet, DeleteSubnet). The API
handlers now call dispatcher.Dispatch() instead of enqueuing closures
directly, decoupling transport (HTTP today, MQTT tomorrow) from execution.

Signed-off-by: GnomeZworc <nicolas.boufidjeline@g3e.fr>

internal/dispatcher/dispatcher.go

@@ -0,0 +1,29 @@
+package dispatcher
+
+import (
+	"log"
+
+	"git.g3e.fr/syonad/two/pkg/worker"
+	"github.com/dgraph-io/badger/v4"
+)
+
+type Command interface {
+	Execute(db *badger.DB) error
+}
+
+type Dispatcher struct {
+	queue *worker.Queue
+	db    *badger.DB
+}
+
+func New(queue *worker.Queue, db *badger.DB) *Dispatcher {
+	return &Dispatcher{queue: queue, db: db}
+}
+
+func (d *Dispatcher) Dispatch(cmd Command) {
+	d.queue.Submit(func() {
+		if err := cmd.Execute(d.db); err != nil {
+			log.Printf("command error (%T): %v", cmd, err)
+		}
+	})
+}

internal/dispatcher/subnet_commands.go

@@ -0,0 +1,26 @@
+package dispatcher
+
+import "github.com/dgraph-io/badger/v4"
+
+type CreateSubnetCommand struct {
+	Name      string
+	VPC       string
+	VxlanID   int
+	LocalIP   string
+	GatewayIP string
+	CIDR      string
+}
+
+func (c CreateSubnetCommand) Execute(db *badger.DB) error {
+	// TODO: brancher internal/subnet/create.go
+	return nil
+}
+
+type DeleteSubnetCommand struct {
+	Name string
+}
+
+func (c DeleteSubnetCommand) Execute(db *badger.DB) error {
+	// TODO: brancher internal/subnet/delete.go
+	return nil
+}

internal/dispatcher/vpc_commands.go

@@ -0,0 +1,35 @@
+package dispatcher
+
+import (
+	"git.g3e.fr/syonad/two/internal/vpc"
+	"git.g3e.fr/syonad/two/pkg/db/kv"
+	"github.com/dgraph-io/badger/v4"
+)
+
+type CreateVPCCommand struct {
+	Name string
+}
+
+func (c CreateVPCCommand) Execute(db *badger.DB) error {
+	kv.AddInDB(db, "vpc/"+c.Name+"/state", "creating")
+	return vpc.CreateVPC(db, c.Name)
+}
+
+type DeleteVPCCommand struct {
+	Name string
+}
+
+func (c DeleteVPCCommand) Execute(db *badger.DB) error {
+	kv.AddInDB(db, "vpc/"+c.Name+"/state", "deleting")
+	if err := vpc.DeleteVPC(db, c.Name); err != nil {
+		return err
+	}
+	state, err := kv.GetFromDB(db, "vpc/"+c.Name+"/state")
+	if err != nil {
+		return err
+	}
+	if state == "deleted" {
+		kv.DeleteInDB(db, "vpc/"+c.Name)
+	}
+	return nil
+}