Add instance list rest api

README.md

@@ -72,6 +72,8 @@ server:
   # host of the control plane
   host: 127.0.0.1
   grpcPort: 54789 # control plane grpc port
+api:
+  port: 9090 # nginx-agent http api
 # tls options - NOT RECOMMENDED FOR PRODUCTION
 tls:
   enable: false

main.go

@@ -189,6 +189,7 @@ func loadPlugins(commander client.Commander, binary *core.NginxBinaryType, env *
 		plugins.NewFileWatcher(loadedConfig, env),
 		plugins.NewFileWatchThrottle(),
 		plugins.NewEvents(loadedConfig, env, sdkGRPC.NewMessageMeta(uuid.NewString()), binary),
+		plugins.NewAgentAPI(loadedConfig, env, binary),
 	)
 
 	if len(loadedConfig.Nginx.NginxCountingSocket) > 0 {

nginx-agent.conf

@@ -15,6 +15,9 @@ server:
   # provide servername overrides if using SNI
   # metrics: ""
   # command: ""
+api:
+  # port to expose http api
+  port: 9090
 # tls options
 tls:
   # enable tls in the nginx-agent setup for grpcs

src/core/config/config.go

@@ -162,6 +162,7 @@ func GetConfig(clientId string) (*Config, error) {
 		ClientID:              clientId,
 		CloudAccountID:        Viper.GetString(CloudAccountIdKey),
 		Server:                getServer(),
+		AgentAPI:              getAgentAPI(),
 		ConfigDirs:            Viper.GetString(ConfigDirsKey),
 		Log:                   getLog(),
 		TLS:                   getTLS(),
@@ -326,13 +327,19 @@ func getNginx() Nginx {
 func getServer() Server {
 	return Server{
 		Host:     Viper.GetString(ServerHost),
-		GrpcPort: Viper.GetInt(ServerGrpcport),
+		GrpcPort: Viper.GetInt(ServerGrpcPort),
 		Token:    Viper.GetString(ServerToken),
 		Metrics:  Viper.GetString(ServerMetrics),
 		Command:  Viper.GetString(ServerCommand),
 	}
 }
 
+func getAgentAPI() AgentAPI {
+	return AgentAPI{
+		Port: Viper.GetInt(AgentAPIPort),
+	}
+}
+
 func getTLS() TLSConfig {
 	return TLSConfig{
 		Enable:     Viper.GetBool(TlsEnable),

src/core/config/config_test.go

@@ -13,13 +13,13 @@ import (
 	"github.com/stretchr/testify/require"
 
 	agent_config "github.com/nginx/agent/sdk/v2/agent/config"
-
 	sysutils "github.com/nginx/agent/v2/test/utils/system"
 )
 
 const (
 	updatedServerHost         = "192.168.0.1"
-	updatedServerPort         = 11000
+	updatedServerGrpcPort     = 11000
+	updatedAgentAPIPort       = 9010
 	updatedLogLevel           = "fatal"
 	updatedLogPath            = "./test-path"
 	updatedConfigDirs         = "/usr/local/etc/nginx"
@@ -139,6 +139,9 @@ func TestGetConfig(t *testing.T) {
 		assert.Equal(t, Defaults.Server.GrpcPort, config.Server.GrpcPort)
 		assert.Equal(t, Defaults.Server.Command, config.Server.Command)
 		assert.Equal(t, Defaults.Server.Metrics, config.Server.Metrics)
+
+		assert.Equal(t, Defaults.AgentAPI.Port, config.AgentAPI.Port)
+
 		assert.True(t, len(config.AllowedDirectoriesMap) > 0)
 		assert.Equal(t, Defaults.ConfigDirs, config.ConfigDirs)
 		assert.Equal(t, Defaults.TLS.Enable, config.TLS.Enable)
@@ -189,11 +192,12 @@ func TestGetConfig(t *testing.T) {
 		// Check for updated values
 		assert.Equal(t, updatedLogLevel, config.Log.Level)
 		assert.Equal(t, updatedTag, config.DisplayName)
+		assert.Equal(t, []string{updatedTag}, config.Tags)
 
 		// Everything else should still be default
 		assert.Equal(t, Defaults.Server.Host, config.Server.Host)
 		assert.Equal(t, Defaults.Server.GrpcPort, config.Server.GrpcPort)
-		assert.Equal(t, []string{updatedTag}, config.Tags)
+		assert.Equal(t, Defaults.AgentAPI.Port, config.AgentAPI.Port)
 	})
 
 	t.Run("test override defaults with config file values", func(t *testing.T) {
@@ -249,7 +253,8 @@ func TestGetConfig(t *testing.T) {
 		require.NoError(t, err)
 
 		assert.Equal(t, updatedServerHost, config.Server.Host)
-		assert.Equal(t, updatedServerPort, config.Server.GrpcPort)
+		assert.Equal(t, updatedServerGrpcPort, config.Server.GrpcPort)
+		assert.Equal(t, updatedAgentAPIPort, config.AgentAPI.Port)
 		assert.Equal(t, updatedConfTags, config.Tags)
 
 		// Check for updated values

src/core/config/defaults.go

@@ -4,9 +4,9 @@ import (
 	"os"
 	"time"
 
-	"github.com/google/uuid"
-
 	agent_config "github.com/nginx/agent/sdk/v2/agent/config"
+
+	"github.com/google/uuid"
 	log "github.com/sirupsen/logrus"
 )
 
@@ -45,6 +45,9 @@ var (
 			// so setting to random uuid at the moment, tls connection won't work without the auth header
 			Token: uuid.New().String(),
 		},
+		AgentAPI: AgentAPI{
+			Port: 9090,
+		},
 		Nginx: Nginx{
 			Debug:               false,
 			NginxCountingSocket: "unix:/var/run/nginx-agent/nginx.sock",
@@ -107,11 +110,16 @@ const (
 	ServerKey = "server"
 
 	ServerHost     = ServerKey + agent_config.KeyDelimiter + "host"
-	ServerGrpcport = ServerKey + agent_config.KeyDelimiter + "grpcport"
+	ServerGrpcPort = ServerKey + agent_config.KeyDelimiter + "grpcport"
 	ServerToken    = ServerKey + agent_config.KeyDelimiter + "token"
 	ServerMetrics  = ServerKey + agent_config.KeyDelimiter + "metrics"
 	ServerCommand  = ServerKey + agent_config.KeyDelimiter + "command"
 
+	// viper keys used in config
+	APIKey = "api"
+
+	AgentAPIPort = APIKey + agent_config.KeyDelimiter + "port"
+
 	// viper keys used in config
 	TlsKey = "tls"
 
@@ -203,7 +211,7 @@ var (
 			DefaultValue: Defaults.Server.Host,
 		},
 		&IntFlag{
-			Name:         ServerGrpcport,
+			Name:         ServerGrpcPort,
 			Usage:        "The desired GRPC port to use for nginx-agent traffic.",
 			DefaultValue: Defaults.Server.GrpcPort,
 		},
@@ -222,6 +230,12 @@ var (
 			Usage:        "The name of the command server sent in the tls configuration.",
 			DefaultValue: Defaults.Server.Command,
 		},
+		// API Config
+		&IntFlag{
+			Name:         AgentAPIPort,
+			Usage:        "The desired port to use for nginx-agent to expose for HTTP traffic.",
+			DefaultValue: Defaults.AgentAPI.Port,
+		},
 		&StringFlag{
 			Name:         ConfigDirsKey,
 			Usage:        "Defines the paths that you want to grant nginx-agent read/write access to. This key is formatted as a string and follows Unix PATH format.",

src/core/config/types.go

@@ -12,6 +12,7 @@ type Config struct {
 	ClientID              string              `mapstructure:"agent_id" yaml:"-"`
 	CloudAccountID        string              `mapstructure:"cloud_account" yaml:"-"`
 	Server                Server              `mapstructure:"server" yaml:"-"`
+	AgentAPI              AgentAPI            `mapstructure:"api" yaml:"-"`
 	ConfigDirs            string              `mapstructure:"config-dirs" yaml:"-"`
 	Log                   LogConfig           `mapstructure:"log" yaml:"-"`
 	TLS                   TLSConfig           `mapstructure:"tls" yaml:"-"`
@@ -40,6 +41,10 @@ type Server struct {
 	Target string `mapstructure:"target" yaml:"-"`
 }
 
+type AgentAPI struct {
+	Port int `mapstructure:"port" yaml:"-"`
+}
+
 // LogConfig for logging
 type LogConfig struct {
 	Level string `mapstructure:"level" yaml:"-"`

src/plugins/agent_api.go

@@ -0,0 +1,134 @@
+package plugins
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"regexp"
+
+	"github.com/nginx/agent/sdk/v2/proto"
+	"github.com/nginx/agent/v2/src/core"
+	"github.com/nginx/agent/v2/src/core/config"
+
+	log "github.com/sirupsen/logrus"
+)
+
+type AgentAPI struct {
+	config       *config.Config
+	env          core.Environment
+	server       http.Server
+	nginxBinary  core.NginxBinary
+	nginxHandler *NginxHandler
+}
+
+type NginxHandler struct {
+	env         core.Environment
+	nginxBinary core.NginxBinary
+}
+
+func NewAgentAPI(config *config.Config, env core.Environment, nginxBinary core.NginxBinary) *AgentAPI {
+	return &AgentAPI{config: config, env: env, nginxBinary: nginxBinary}
+}
+
+func (a *AgentAPI) Init(core.MessagePipeInterface) {
+	log.Info("Agent API initializing")
+	go a.createHttpServer()
+}
+
+func (a *AgentAPI) Close() {
+	log.Info("Agent API is wrapping up")
+	if err := a.server.Shutdown(context.Background()); err != nil {
+		log.Errorf("Agent API HTTP Server Shutdown Error: %v", err)
+	}
+}
+
+func (a *AgentAPI) Process(message *core.Message) {
+	log.Tracef("Process function in the agent_api.go, %s %v", message.Topic(), message.Data())
+}
+
+func (a *AgentAPI) Info() *core.Info {
+	return core.NewInfo("Agent API Plugin", "v0.0.1")
+}
+
+func (a *AgentAPI) Subscriptions() []string {
+	return []string{}
+}
+
+func (a *AgentAPI) createHttpServer() {
+	mux := http.NewServeMux()
+	a.nginxHandler = &NginxHandler{a.env, a.nginxBinary}
+	mux.Handle("/nginx/", a.nginxHandler)
+
+	log.Debug("Starting Agent API HTTP server")
+
+	a.server = http.Server{
+		Addr:    fmt.Sprintf(":%d", a.config.AgentAPI.Port),
+		Handler: mux,
+	}
+
+	if err := a.server.ListenAndServe(); err != http.ErrServerClosed {
+		log.Fatalf("error listening to port: %v", err)
+	}
+}
+
+var (
+	instancesRegex = regexp.MustCompile(`^\/nginx[\/]*$`)
+)
+
+func (h *NginxHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("content-type", "application/json")
+	switch {
+	case r.Method == http.MethodGet && instancesRegex.MatchString(r.URL.Path):
+		err := sendInstanceDetailsPayload(h.getNginxDetails(), w, r)
+		if err != nil {
+			log.Warnf("Failed to send instance details payload: %v", err)
+		}
+	default:
+		w.WriteHeader(http.StatusNotFound)
+		_, err := fmt.Fprint(w, []byte("not found"))
+		if err != nil {
+			log.Warnf("Failed to send api response: %v", err)
+		}
+	}
+}
+
+func sendInstanceDetailsPayload(nginxDetails []*proto.NginxDetails, w http.ResponseWriter, r *http.Request) error {
+	w.WriteHeader(http.StatusOK)
+
+	if len(nginxDetails) == 0 {
+		log.Debug("No nginx instances found")
+		_, err := fmt.Fprint(w, "[]")
+		if err != nil {
+			return fmt.Errorf("failed to send payload: %v", err)
+		}
+
+		return nil
+	}
+
+	respBody := new(bytes.Buffer)
+	err := json.NewEncoder(respBody).Encode(nginxDetails)
+	if err != nil {
+		return fmt.Errorf("failed to encode payload: %v", err)
+	}
+
+	_, err = fmt.Fprint(w, respBody)
+	if err != nil {
+		return fmt.Errorf("failed to send payload: %v", err)
+	}
+
+	return nil
+}
+
+func (h *NginxHandler) getNginxDetails() []*proto.NginxDetails {
+	var nginxDetails []*proto.NginxDetails
+
+	for _, proc := range h.env.Processes() {
+		if proc.IsMaster {
+			nginxDetails = append(nginxDetails, h.nginxBinary.GetNginxDetailsFromProcess(proc))
+		}
+	}
+
+	return nginxDetails
+}