Feature/unixsock

pkg/exporter/cmd/config.go

@@ -8,8 +8,12 @@ import (
 )
 
 type InspServerConfig struct {
-	DebugMode        bool          `yaml:"debugMode" mapstructure:"debugMode" json:"debugMode"`
-	Port             uint16        `yaml:"port" mapstructure:"port" json:"port"`
+	DebugMode bool `yaml:"debugMode" mapstructure:"debugMode" json:"debugMode"`
+	// A better way to set listen port is a `address` field  that can be used for bind interface ip, or even unix domain socket
+	// Deprecated: use address instead
+	Port uint16 `yaml:"port" mapstructure:"port" json:"port"`
+
+	Address          string        `yaml:"address" mapstructure:"address" json:"address"`
 	EnableController bool          `yaml:"enableController" mapstructure:"enableController" json:"enableController"`
 	MetricsConfig    MetricsConfig `yaml:"metrics" mapstructure:"metrics" json:"metrics"`
 	EventConfig      EventConfig   `yaml:"event" mapstructure:"event" json:"event"`

pkg/exporter/cmd/server.go

@@ -6,11 +6,16 @@ package cmd
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
+	"net"
 	"net/http"
+	"net/url"
 	"os"
 	"os/signal"
+	"path"
 	"reflect"
+	"strings"
 	"sync"
 	"sync/atomic"
 	"syscall"
@@ -92,7 +97,6 @@ type ProbeManager[T probe.Probe] interface {
 	StartProbe(ctx context.Context, probe T) error
 	StopProbe(ctx context.Context, probe T) error
 }
-
 type DynamicProbeServer[T probe.Probe] struct {
 	lock         sync.Mutex
 	probeManager ProbeManager[T]
@@ -280,7 +284,57 @@ func (i *inspServer) reload() error {
 	return nil
 }
 
-func (i *inspServer) newHTTPServer(cfg *InspServerConfig) *http.Server {
+func (i *inspServer) createListener(cfg *InspServerConfig) (net.Listener, error) {
+	if cfg.Address == "" {
+		if cfg.Port != 0 {
+			cfg.Address = fmt.Sprintf(":%d", cfg.Port)
+			log.Warningf("port is derepcated, use address instead")
+		} else {
+			return nil, fmt.Errorf("listen address is empty")
+		}
+	}
+
+	rawAddr := cfg.Address
+	if !strings.Contains(rawAddr, "//") {
+		log.Infof("address contains no protocol part, use tcp:// by default")
+		rawAddr = "tcp://" + rawAddr
+	}
+
+	protocol := ""
+	addr := ""
+
+	u, err := url.Parse(rawAddr)
+	if err != nil {
+		return nil, fmt.Errorf("invalid address %s, valid format is [protocol://]addr[:port]", cfg.Address)
+	}
+	protocol = u.Scheme
+	switch protocol {
+	case "unix":
+		// For Unix domain sockets, the path is in the opaque part
+		addr = strings.TrimPrefix(cfg.Address, "unix://")
+		if _, err = os.Stat(addr); err != nil {
+			if !errors.Is(err, os.ErrNotExist) {
+				return nil, fmt.Errorf("failed stat sock file %s: %w", addr, err)
+			}
+			parent := path.Dir(addr)
+			if err = os.MkdirAll(parent, 0o755); err != nil {
+				return nil, fmt.Errorf("failed create director %s: %w", parent, err)
+			}
+		} else {
+			//socket file exists, just remove it
+			_ = os.Remove(addr)
+		}
+	case "tcp":
+		host, port, _ := net.SplitHostPort(cfg.Address)
+		addr = fmt.Sprintf("%s:%s", host, port)
+	default:
+		return nil, fmt.Errorf("unsupported protocol %s, only `tcp` and 'unix' are supported", protocol)
+	}
+
+	return net.Listen(protocol, addr)
+}
+
+func (i *inspServer) newHTTPServer(cfg *InspServerConfig) (*http.Server, net.Listener, error) {
 	http.Handle("/metrics", i.metricsServer)
 	http.Handle("/", http.HandlerFunc(defaultPage))
 	http.Handle("/status", http.HandlerFunc(i.statusPage))
@@ -293,9 +347,14 @@ func (i *inspServer) newHTTPServer(cfg *InspServerConfig) *http.Server {
 		)
 		http.Handle("/internal", promhttp.HandlerFor(reg, promhttp.HandlerOpts{Registry: reg}))
 	}
-	listenAddr := fmt.Sprintf(":%d", cfg.Port)
-	log.Infof("inspector start metric server, listenAddr: %s", listenAddr)
-	return &http.Server{Addr: listenAddr}
+
+	listener, err := i.createListener(cfg)
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed create listener: %w", err)
+	}
+
+	log.Infof("inspector start metric server, listenAddr: %s", listener.Addr())
+	return &http.Server{}, listener, nil
 }
 
 func (i *inspServer) start(cfg *InspServerConfig) error {
@@ -350,11 +409,14 @@ func (i *inspServer) start(cfg *InspServerConfig) error {
 		log.Errorf("failed watch config, dynamic load would not work: %v", err)
 	}
 
-	srv := i.newHTTPServer(cfg)
+	srv, listener, err := i.newHTTPServer(cfg)
+	if err != nil {
+		return fmt.Errorf("failed start http server: %w", err)
+	}
 	serverClosedChan := make(chan struct{})
 	serverClosed := false
 	go func() {
-		if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+		if err := srv.Serve(listener); err != nil && err != http.ErrServerClosed {
 			log.Errorf("server error: %v", err)
 		}
 
@@ -364,9 +426,12 @@ func (i *inspServer) start(cfg *InspServerConfig) error {
 
 	WaitSignals(serverClosedChan, syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM)
 	close(done)
+
 	if !serverClosed {
 		_ = srv.Shutdown(ctx)
 	}
+	_ = listener.Close()
+
 	return nil
 }