feat: introduce cluster agent

pkg/cluster/agent.go

@@ -0,0 +1,55 @@
+package cluster
+
+import (
+	"log"
+
+	"github.com/0x1d/rcond/pkg/config"
+	"github.com/hashicorp/serf/serf"
+)
+
+type Agent struct {
+	Serf *serf.Serf
+}
+
+func NewAgent(clusterConfig *config.ClusterConfig) (*Agent, error) {
+	config := serf.DefaultConfig()
+	config.NodeName = clusterConfig.NodeName
+	config.ProtocolVersion = serf.ProtocolVersionMax
+	config.MemberlistConfig.SecretKey = []byte(clusterConfig.SecretKey)
+	config.MemberlistConfig.AdvertiseAddr = clusterConfig.AdvertiseAddr
+	config.MemberlistConfig.AdvertisePort = clusterConfig.AdvertisePort
+	config.MemberlistConfig.BindAddr = clusterConfig.BindAddr
+	config.MemberlistConfig.BindPort = clusterConfig.BindPort
+
+	serf, err := serf.Create(config)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Agent{Serf: serf}, nil
+}
+
+func (a *Agent) Members() ([]serf.Member, error) {
+	log.Printf("Getting members of the cluster")
+	return a.Serf.Members(), nil
+}
+
+func (a *Agent) Join(addrs []string, ignoreOld bool) (int, error) {
+	log.Printf("Joining nodes in the cluster: %v", addrs)
+	n, err := a.Serf.Join(addrs, ignoreOld)
+	if err != nil {
+		log.Printf("Failed to join nodes in the cluster: %v", err)
+		return 0, err
+	}
+	log.Printf("Joined %d nodes in the cluster", n)
+	return n, nil
+}
+
+func (a *Agent) Leave() error {
+	return a.Serf.Leave()
+}
+
+func (a *Agent) Shutdown() error {
+	log.Printf("Shutting down cluster agent")
+	return a.Serf.Shutdown()
+}

pkg/config/config.go

@@ -7,7 +7,8 @@ import (
 )
 
 type Config struct {
-	Rcond RcondConfig `yaml:"rcond"`
+	Rcond   RcondConfig   `yaml:"rcond"`
+	Cluster ClusterConfig `yaml:"cluster"`
 }
 
 type RcondConfig struct {
@@ -15,6 +16,17 @@ type RcondConfig struct {
 	ApiToken string `yaml:"api_token"`
 }
 
+type ClusterConfig struct {
+	Enabled       bool     `yaml:"enabled"`
+	NodeName      string   `yaml:"node_name"`
+	SecretKey     string   `yaml:"secret_key"`
+	Join          []string `yaml:"join"`
+	AdvertiseAddr string   `yaml:"advertise_addr"`
+	AdvertisePort int      `yaml:"advertise_port"`
+	BindAddr      string   `yaml:"bind_addr"`
+	BindPort      int      `yaml:"bind_port"`
+}
+
 func LoadConfig(path string) (*Config, error) {
 	yamlFile, err := os.ReadFile(path)
 	if err != nil {

pkg/http/handlers.go

@@ -6,6 +6,7 @@ import (
 	"log"
 	"net/http"
 
+	"github.com/0x1d/rcond/pkg/cluster"
 	network "github.com/0x1d/rcond/pkg/network"
 	"github.com/0x1d/rcond/pkg/system"
 	"github.com/0x1d/rcond/pkg/user"
@@ -287,3 +288,24 @@ func HandleShutdown(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Content-Type", "application/json")
 	json.NewEncoder(w).Encode(map[string]string{"status": "success"})
 }
+
+func ClusterAgentWrapper(agent *cluster.Agent) func(http.ResponseWriter, *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		HandleClusterMembers(w, r, agent)
+	}
+}
+
+func HandleClusterMembers(w http.ResponseWriter, r *http.Request, agent *cluster.Agent) {
+	if agent == nil {
+		writeError(w, "cluster agent is not initialized", http.StatusInternalServerError)
+		return
+	}
+	members, err := agent.Members()
+	if err != nil {
+		writeError(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	json.NewEncoder(w).Encode(members)
+}

pkg/http/server.go

@@ -6,14 +6,16 @@ import (
 	"net/http"
 	"time"
 
+	"github.com/0x1d/rcond/pkg/cluster"
 	"github.com/0x1d/rcond/pkg/config"
 	"github.com/gorilla/mux"
 )
 
 type Server struct {
-	router   *mux.Router
-	srv      *http.Server
-	apiToken string
+	router       *mux.Router
+	srv          *http.Server
+	apiToken     string
+	clusterAgent *cluster.Agent
 }
 
 func NewServer(cfg *config.Config) *Server {
@@ -37,6 +39,11 @@ func NewServer(cfg *config.Config) *Server {
 	}
 }
 
+func (s *Server) WithClusterAgent(agent *cluster.Agent) *Server {
+	s.clusterAgent = agent
+	return s
+}
+
 func (s *Server) Start() error {
 	return s.srv.ListenAndServe()
 }
@@ -69,6 +76,7 @@ func (s *Server) RegisterRoutes() {
 	s.router.HandleFunc("/users/{user}/keys/{fingerprint}", s.verifyToken(HandleRemoveAuthorizedKey)).Methods(http.MethodDelete)
 	s.router.HandleFunc("/system/restart", s.verifyToken(HandleReboot)).Methods(http.MethodPost)
 	s.router.HandleFunc("/system/shutdown", s.verifyToken(HandleShutdown)).Methods(http.MethodPost)
+	s.router.HandleFunc("/cluster/members", s.verifyToken(ClusterAgentWrapper(s.clusterAgent))).Methods(http.MethodGet)
 }
 
 func (s *Server) healthHandler(w http.ResponseWriter, r *http.Request) {