Temporary remove static backend registration

README.md

@@ -18,18 +18,19 @@ make build
 Basic usage:
 
 ```bash
-# Start the load balancer with 2 backends
-./bin/plumber --backends http://localhost:8080,http://localhost:8081
+# Start the load balancer
+./bin/plumber
 ```
 
-Docker-compose testing:
+To test plumber, you need server instances managed by Docker.
+You can use the following command to start the server instances:
 
 ```bash
 # Test the load balancer with docker-compose
 make docker-compose-up
 
-# Start the load balancer
-./bin/plumber
+# Start the load balancer with target backend image for service discovery
+./bin/plumber --target-backend-image yorkieteam/yorkie
 
 # Send a request to the load balancer
 chmod +x ./scripts/lb_distribution_test.sh
@@ -59,5 +60,4 @@ The following features are planned to be implemented first:
 
 ### v0.x.x
 
-- [ ] Support rate limiter
-- [ ] TBD
+- [ ] TBD

cmd/root.go

@@ -19,7 +19,6 @@ package cmd
 import (
 	"fmt"
 	"os"
-	"strings"
 
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
@@ -37,33 +36,19 @@ var rootCmd = &cobra.Command{
 	// Uncomment the following line if your bare application
 	// has an action associated with it:
 	Run: func(cmd *cobra.Command, args []string) {
-		serviceDiscovery, err := cmd.Flags().GetBool("service-discovery")
-		if err != nil {
-			fmt.Println(err)
-			os.Exit(1)
-		}
-
 		targetBackendImage, err := cmd.Flags().GetString("target-backend-image")
 		if err != nil {
 			fmt.Println(err)
 			os.Exit(1)
 		}
 
-		backendList, err := cmd.Flags().GetString("backends")
-		if err != nil {
-			fmt.Println(err)
-			os.Exit(1)
-		}
-
-		backendAddresses := strings.Split(backendList, ",")
-
-		agent, err := internal.NewAgent(serviceDiscovery, targetBackendImage)
+		agent, err := internal.NewAgent(targetBackendImage)
 		if err != nil {
 			fmt.Println(err)
 			os.Exit(1)
 		}
 
-		if err = agent.Run(backendAddresses); err != nil {
+		if err = agent.Run(); err != nil {
 			fmt.Println(err)
 			os.Exit(1)
 		}
@@ -92,9 +77,6 @@ func init() {
 	// when this action is called directly.
 	rootCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")
 
-	rootCmd.Flags().String("backends", "", "Backend address")
-
-	rootCmd.Flags().BoolP("service-discovery", "s", true, "Enable service discovery")
 	rootCmd.Flags().String("target-backend-image", "traefik/whoami", "Target backend image for service discovery")
 }
 

internal/agent.go

@@ -4,18 +4,15 @@ import (
 	"log"
 	"net/http"
 
-	"github.com/krapie/plumber/internal/backend"
 	"github.com/krapie/plumber/internal/loadbalancer"
 	"github.com/krapie/plumber/internal/loadbalancer/maglev"
 )
 
 type Agent struct {
 	loadBalancer loadbalancer.LoadBalancer
-
-	serviceDiscovery bool
 }
 
-func NewAgent(serviceDiscovery bool, targetBackendImage string) (*Agent, error) {
+func NewAgent(targetBackendImage string) (*Agent, error) {
 	// TODO(krapie): we fix LB configuration maglev for now, but we can make it configurable
 	loadBalancer, err := maglev.NewLB(targetBackendImage)
 	if err != nil {
@@ -24,19 +21,10 @@ func NewAgent(serviceDiscovery bool, targetBackendImage string) (*Agent, error)
 
 	return &Agent{
 		loadBalancer: loadBalancer,
-
-		serviceDiscovery: serviceDiscovery,
 	}, nil
 }
 
-func (s *Agent) Run(backendAddresses []string) error {
-	if !s.serviceDiscovery {
-		err := s.addBackends(backendAddresses)
-		if err != nil {
-			return err
-		}
-	}
-
+func (s *Agent) Run() error {
 	http.HandleFunc("/", s.loadBalancer.ServeProxy)
 
 	// TODO(krapie): temporary specify yorkie related path because http.HandleFunc only support exact match
@@ -57,19 +45,3 @@ func (s *Agent) Run(backendAddresses []string) error {
 
 	return nil
 }
-
-func (s *Agent) addBackends(backendAddresses []string) error {
-	for _, addr := range backendAddresses {
-		b, err := backend.NewDefaultBackend(addr, addr)
-		if err != nil {
-			return err
-		}
-
-		err = s.loadBalancer.AddBackend(b)
-		if err != nil {
-			return err
-		}
-	}
-
-	return nil
-}

internal/loadbalancer/load_balancer.go

@@ -2,15 +2,9 @@ package loadbalancer
 
 import (
 	"net/http"
-
-	"github.com/krapie/plumber/internal/backend"
 )
 
 // LoadBalancer is an interface for a load balancer.
 type LoadBalancer interface {
 	ServeProxy(rw http.ResponseWriter, req *http.Request)
-
-	// TODO(krapie): deprecate methods below
-	AddBackend(b *backend.Backend) error
-	GetBackends() []*backend.Backend
 }

internal/loadbalancer/maglev/maglev_lb.go

@@ -4,7 +4,6 @@ import (
 	"log"
 	"net/http"
 
-	"github.com/krapie/plumber/internal/backend"
 	"github.com/krapie/plumber/internal/backend/health"
 	"github.com/krapie/plumber/internal/backend/register"
 	"github.com/krapie/plumber/internal/backend/register/docker"
@@ -57,35 +56,6 @@ func NewLB(targetBackendImage string) (*MaglevLB, error) {
 	}, nil
 }
 
-func (lb *MaglevLB) AddBackend(b *backend.Backend) error {
-	err := lb.backendRegistry.AddBackend(b.ID, b.Addr.String())
-	if err != nil {
-		return err
-	}
-
-	err = lb.lookupTable.Add(b.ID)
-	if err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func (lb *MaglevLB) RemoveBackend(b *backend.Backend) error {
-	lb.backendRegistry.RemoveBackendByID(b.ID)
-
-	err := lb.lookupTable.Remove(b.ID)
-	if err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func (lb *MaglevLB) GetBackends() []*backend.Backend {
-	return lb.backendRegistry.GetBackends()
-}
-
 // ServeProxy serves the request to the next backend in the list
 // keep in mind that this function and its sub functions need to be thread safe
 func (lb *MaglevLB) ServeProxy(rw http.ResponseWriter, req *http.Request) {

internal/loadbalancer/round_robin/round_robin_lb.go

@@ -52,19 +52,6 @@ func NewLB(targetBackendImage string) (*RoundRobinLB, error) {
 	}, nil
 }
 
-func (lb *RoundRobinLB) AddBackend(b *backend.Backend) error {
-	err := lb.backendRegistry.AddBackend(b.ID, b.Addr.String())
-	if err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func (lb *RoundRobinLB) GetBackends() []*backend.Backend {
-	return lb.backendRegistry.GetBackends()
-}
-
 // ServeProxy serves the request to the next backend in the list
 // keep in mind that this function and its sub functions need to be thread safe
 func (lb *RoundRobinLB) ServeProxy(rw http.ResponseWriter, req *http.Request) {