agent: adding HTTP server

command/agent/command.go

@@ -36,10 +36,11 @@ type Command struct {
 	Ui                cli.Ui
 	ShutdownCh        <-chan struct{}
 
-	args      []string
-	agent     *Agent
-	logFilter *logutils.LevelFilter
-	logOutput io.Writer
+	args       []string
+	agent      *Agent
+	httpServer *HTTPServer
+	logFilter  *logutils.LevelFilter
+	logOutput  io.Writer
 }
 
 func (c *Command) readConfig() *Config {
@@ -145,6 +146,14 @@ func (c *Command) setupAgent(config *Config, logOutput io.Writer) error {
 	}
 	c.agent = agent
 
+	http, err := NewHTTPServer(agent, config, logOutput)
+	if err != nil {
+		agent.Shutdown()
+		c.Ui.Error(fmt.Sprintf("Error starting http server: %s", err))
+		return err
+	}
+	c.httpServer = http
+
 	// Setup update checking
 	if !config.DisableUpdateCheck {
 		version := config.Version

command/agent/config.go

@@ -27,6 +27,9 @@ type Config struct {
 	// If not specified, 127.0.0.1:4646 is used.
 	HttpAddr string `hcl:"http_addr"`
 
+	// EnableDebug is used to enable debugging HTTP endpoints
+	EnableDebug bool `hcl:"enable_debug"`
+
 	// Client has our client related settings
 	Client *ClientConfig `hcl:"client"`
 
@@ -105,7 +108,9 @@ func DevConfig() *Config {
 		Server: &ServerConfig{
 			Enabled: true,
 		},
-		DevMode: true,
+		DevMode:                   true,
+		EnableDebug:               true,
+		DisableAnonymousSignature: true,
 	}
 }
 

command/agent/http.go

@@ -0,0 +1,61 @@
+package agent
+
+import (
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"net/http"
+	"net/http/pprof"
+)
+
+// HTTPServer is used to wrap an Agent and expose it over an HTTP interface
+type HTTPServer struct {
+	agent    *Agent
+	mux      *http.ServeMux
+	listener net.Listener
+	logger   *log.Logger
+}
+
+// NewHTTPServer starts new HTTP server over the agent
+func NewHTTPServer(agent *Agent, config *Config, logOutput io.Writer) (*HTTPServer, error) {
+	// Start the listener
+	ln, err := net.Listen("tcp", config.HttpAddr)
+	if err != nil {
+		return nil, fmt.Errorf("failed to start HTTP listener on %s: %v", config.HttpAddr, err)
+	}
+
+	// Create the mux
+	mux := http.NewServeMux()
+
+	// Create the server
+	srv := &HTTPServer{
+		agent:    agent,
+		mux:      mux,
+		listener: ln,
+		logger:   log.New(logOutput, "", log.LstdFlags),
+	}
+	srv.registerHandlers(config.EnableDebug)
+
+	// Start the server
+	go http.Serve(ln, mux)
+	return srv, nil
+}
+
+// Shutdown is used to shutdown the HTTP server
+func (s *HTTPServer) Shutdown() {
+	if s != nil {
+		s.logger.Printf("[DEBUG] http: Shutting down http server")
+		s.listener.Close()
+	}
+}
+
+// registerHandlers is used to attach our handlers to the mux
+func (s *HTTPServer) registerHandlers(enableDebug bool) {
+	if enableDebug {
+		s.mux.HandleFunc("/debug/pprof/", pprof.Index)
+		s.mux.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
+		s.mux.HandleFunc("/debug/pprof/profile", pprof.Profile)
+		s.mux.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
+	}
+}