f-21: dispatch: add a prepare step to dispatch

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

internal/api/agent/subnet.go

@@ -61,8 +61,15 @@ func (s *Server) getSubnet(w http.ResponseWriter, _ *http.Request, name string)
 	json.NewEncoder(w).Encode(sub)
 }
 
-func (s *Server) deleteSubnet(w http.ResponseWriter, r *http.Request, name string) {
+func (s *Server) deleteSubnet(w http.ResponseWriter, _ *http.Request, name string) {
-	s.dispatcher.Dispatch(dispatcher.DeleteSubnetCommand{Name: name})
+	cmd := dispatcher.DeleteSubnetCommand{Name: name}
+	if err := s.dispatcher.Prepare(cmd); err != nil {
+		w.WriteHeader(http.StatusNotFound)
+		json.NewEncoder(w).Encode(ErrorResponse{Error: err.Error()})
+		return
+	}
+	s.dispatcher.Dispatch(cmd)
+	state, _ := kv.GetFromDB(s.db, "subnet/"+name+"/state")
 	w.WriteHeader(http.StatusAccepted)
-	json.NewEncoder(w).Encode(Subnet{Name: name, State: "deleting"})
+	json.NewEncoder(w).Encode(Subnet{Name: name, State: state})
 }

internal/api/agent/subnets.go

@@ -74,21 +74,42 @@ func (s *Server) postSubnet(w http.ResponseWriter, r *http.Request) {
 		json.NewEncoder(w).Encode(ErrorResponse{Error: "name, vpc, iface_type, gateway_ip and cidr are required"})
 		return
 	}
-	s.dispatcher.Dispatch(dispatcher.CreateSubnetCommand{
+	cmd := dispatcher.CreateSubnetCommand{
 		Name:      req.Name,
 		VPC:       req.VPC,
 		VxlanID:   req.VxlanID,
 		IfaceType: req.IfaceType,
 		GatewayIP: req.GatewayIP,
 		CIDR:      req.CIDR,
-	})
+	}
+	if err := s.dispatcher.Prepare(cmd); err != nil {
+		w.WriteHeader(http.StatusConflict)
+		json.NewEncoder(w).Encode(ErrorResponse{Error: err.Error()})
+		return
+	}
+	s.dispatcher.Dispatch(cmd)
+	entries, _ := kv.ListByPrefix(s.db, "subnet/"+req.Name+"/")
+	sub := Subnet{Name: req.Name}
+	for key, value := range entries {
+		parts := strings.Split(key, "/")
+		if len(parts) != 3 {
+			continue
+		}
+		switch parts[2] {
+		case "state":
+			sub.State = value
+		case "vpc":
+			sub.VPC = value
+		case "vxlan_id":
+			sub.VxlanID, _ = strconv.Atoi(value)
+		case "local_iface":
+			sub.LocalIface = value
+		case "gateway_ip":
+			sub.GatewayIP = value
+		case "cidr":
+			sub.CIDR = value
+		}
+	}
 	w.WriteHeader(http.StatusAccepted)
-	json.NewEncoder(w).Encode(Subnet{
+	json.NewEncoder(w).Encode(sub)
-		Name:      req.Name,
-		State:     "creating",
-		VPC:       req.VPC,
-		VxlanID:   req.VxlanID,
-		GatewayIP: req.GatewayIP,
-		CIDR:      req.CIDR,
-	})
 }

internal/api/agent/vpc.go

@@ -40,7 +40,14 @@ func (s *Server) getVpc(w http.ResponseWriter, _ *http.Request, name string) {
 }
 
 func (s *Server) deleteVpc(w http.ResponseWriter, _ *http.Request, name string) {
-	s.dispatcher.Dispatch(dispatcher.DeleteVPCCommand{Name: name})
+	cmd := dispatcher.DeleteVPCCommand{Name: name}
+	if err := s.dispatcher.Prepare(cmd); err != nil {
+		w.WriteHeader(http.StatusNotFound)
+		json.NewEncoder(w).Encode(ErrorResponse{Error: err.Error()})
+		return
+	}
+	s.dispatcher.Dispatch(cmd)
+	state, _ := kv.GetFromDB(s.db, "vpc/"+name+"/state")
 	w.WriteHeader(http.StatusAccepted)
-	json.NewEncoder(w).Encode(VPC{Name: name, State: "deleting"})
+	json.NewEncoder(w).Encode(VPC{Name: name, State: state})
 }

internal/api/agent/vpcs.go

@@ -62,7 +62,14 @@ func (s *Server) postVpc(w http.ResponseWriter, r *http.Request) {
 		json.NewEncoder(w).Encode(ErrorResponse{Error: "name is required"})
 		return
 	}
-	s.dispatcher.Dispatch(dispatcher.CreateVPCCommand{Name: req.Name})
+	cmd := dispatcher.CreateVPCCommand{Name: req.Name}
+	if err := s.dispatcher.Prepare(cmd); err != nil {
+		w.WriteHeader(http.StatusConflict)
+		json.NewEncoder(w).Encode(ErrorResponse{Error: err.Error()})
+		return
+	}
+	s.dispatcher.Dispatch(cmd)
+	state, _ := kv.GetFromDB(s.db, "vpc/"+req.Name+"/state")
 	w.WriteHeader(http.StatusAccepted)
-	json.NewEncoder(w).Encode(VPC{Name: req.Name, State: "creating"})
+	json.NewEncoder(w).Encode(VPC{Name: req.Name, State: state})
 }

internal/dispatcher/agent/dispatcher.go

@@ -9,6 +9,7 @@ import (
 )
 
 type Command interface {
+	Prepare(db *badger.DB, cfg *configuration.Config) error
 	Execute(db *badger.DB, cfg *configuration.Config) error
 }
 
@@ -22,6 +23,10 @@ func New(queue *worker.Queue, db *badger.DB, cfg *configuration.Config) *Dispatc
 	return &Dispatcher{queue: queue, db: db, cfg: cfg}
 }
 
+func (d *Dispatcher) Prepare(cmd Command) error {
+	return cmd.Prepare(d.db, d.cfg)
+}
+
 func (d *Dispatcher) Dispatch(cmd Command) {
 	d.queue.Submit(func() {
 		if err := cmd.Execute(d.db, d.cfg); err != nil {

internal/dispatcher/agent/subnet_commands.go

@@ -20,7 +20,17 @@ type CreateSubnetCommand struct {
 	CIDR      string
 }
 
-func (c CreateSubnetCommand) Execute(db *badger.DB, cfg *configuration.Config) error {
+func (c CreateSubnetCommand) Prepare(db *badger.DB, cfg *configuration.Config) error {
+	if _, err := kv.GetFromDB(db, "subnet/"+c.Name+"/state"); err == nil {
+		return fmt.Errorf("subnet %q already exists", c.Name)
+	}
+	vpcState, err := kv.GetFromDB(db, "vpc/"+c.VPC+"/state")
+	if err != nil {
+		return fmt.Errorf("vpc %q not found", c.VPC)
+	}
+	if vpcState == "deleting" || vpcState == "deleted" {
+		return fmt.Errorf("vpc %q is %s", c.VPC, vpcState)
+	}
 	localIface, ok := cfg.Interfaces[c.IfaceType]
 	if !ok {
 		localIface = cfg.DefaultInterface
@@ -31,6 +41,10 @@ func (c CreateSubnetCommand) Execute(db *badger.DB, cfg *configuration.Config) e
 	kv.AddInDB(db, "subnet/"+c.Name+"/local_iface", localIface)
 	kv.AddInDB(db, "subnet/"+c.Name+"/gateway_ip", c.GatewayIP)
 	kv.AddInDB(db, "subnet/"+c.Name+"/cidr", c.CIDR)
+	return nil
+}
+
+func (c CreateSubnetCommand) Execute(db *badger.DB, _ *configuration.Config) error {
 	return subnet.CreateSubnet(db, c.Name)
 }
 
@@ -38,8 +52,14 @@ type DeleteSubnetCommand struct {
 	Name string
 }
 
+func (c DeleteSubnetCommand) Prepare(db *badger.DB, _ *configuration.Config) error {
+	if _, err := kv.GetFromDB(db, "subnet/"+c.Name+"/state"); err != nil {
+		return fmt.Errorf("subnet %q not found", c.Name)
+	}
+	return kv.AddInDB(db, "subnet/"+c.Name+"/state", "deleting")
+}
+
 func (c DeleteSubnetCommand) Execute(db *badger.DB, _ *configuration.Config) error {
-	kv.AddInDB(db, "subnet/"+c.Name+"/state", "deleting")
 	if err := subnet.DeleteSubnet(db, c.Name); err != nil {
 		fmt.Println(err)
 		os.Exit(1)

internal/dispatcher/agent/vpc_commands.go

@@ -1,6 +1,8 @@
 package dispatcher
 
 import (
+	"fmt"
+
 	configuration "git.g3e.fr/syonad/two/internal/config/agent"
 	"git.g3e.fr/syonad/two/internal/vpc"
 	"git.g3e.fr/syonad/two/pkg/db/kv"
@@ -11,8 +13,14 @@ type CreateVPCCommand struct {
 	Name string
 }
 
+func (c CreateVPCCommand) Prepare(db *badger.DB, _ *configuration.Config) error {
+	if _, err := kv.GetFromDB(db, "vpc/"+c.Name+"/state"); err == nil {
+		return fmt.Errorf("vpc %q already exists", c.Name)
+	}
+	return kv.AddInDB(db, "vpc/"+c.Name+"/state", "creating")
+}
+
 func (c CreateVPCCommand) Execute(db *badger.DB, _ *configuration.Config) error {
-	kv.AddInDB(db, "vpc/"+c.Name+"/state", "creating")
 	return vpc.CreateVPC(db, c.Name)
 }
 
@@ -20,8 +28,14 @@ type DeleteVPCCommand struct {
 	Name string
 }
 
+func (c DeleteVPCCommand) Prepare(db *badger.DB, _ *configuration.Config) error {
+	if _, err := kv.GetFromDB(db, "vpc/"+c.Name+"/state"); err != nil {
+		return fmt.Errorf("vpc %q not found", c.Name)
+	}
+	return kv.AddInDB(db, "vpc/"+c.Name+"/state", "deleting")
+}
+
 func (c DeleteVPCCommand) Execute(db *badger.DB, _ *configuration.Config) error {
-	kv.AddInDB(db, "vpc/"+c.Name+"/state", "deleting")
 	if err := vpc.DeleteVPC(db, c.Name); err != nil {
 		return err
 	}