feature: support dlopen for prober plugin (#588)

src/modules/monapi/plugins/all/dlopen.go

@@ -0,0 +1,57 @@
+package all
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"plugin"
+	"strings"
+)
+
+const pluginDir = "plugins"
+
+func init() {
+	plugins, err := listPlugins(pluginDir)
+	if err != nil {
+		fmt.Printf("list plugins: \n", err)
+		return
+	}
+
+	for _, file := range plugins {
+		_, err := plugin.Open(file)
+		if err != nil {
+			fmt.Printf("plugin.Open %s err %s\n", file, err)
+			continue
+		}
+	}
+}
+
+func listPlugins(dir string) ([]string, error) {
+	df, err := os.Open(dir)
+	if err != nil {
+		return nil, fmt.Errorf("failed opening directory: %s", err)
+	}
+	defer df.Close()
+
+	list, err := df.Readdirnames(0) // 0 to read all files and folders
+	if err != nil {
+		return nil, fmt.Errorf("read dir names: %s", err)
+	}
+
+	var plugins []string
+	for _, name := range list {
+		if !strings.HasSuffix(name, ".so") {
+			continue
+		}
+
+		file := filepath.Join(dir, name)
+		if fi, err := os.Stat(file); err != nil {
+			continue
+		} else if fi.IsDir() {
+			continue
+		}
+		plugins = append(plugins, file)
+	}
+
+	return plugins, nil
+}

src/modules/monapi/plugins/demo/lib/Makefile

@@ -0,0 +1,4 @@
+all: lib.so
+
+lib.so: lib.go
+	go build -buildmode=plugin -o $@

src/modules/monapi/plugins/demo/lib/lib.go

@@ -0,0 +1,5 @@
+package main
+
+import (
+	_ "github.com/didi/nightingale/src/modules/monapi/plugins/demo"
+)

src/modules/prober/prober.go

@@ -19,6 +19,7 @@ import (
 	"github.com/didi/nightingale/src/modules/prober/http"
 	"github.com/didi/nightingale/src/modules/prober/manager"
 
+	"github.com/didi/nightingale/src/modules/monapi/collector"
 	_ "github.com/didi/nightingale/src/modules/monapi/plugins/all"
 	_ "github.com/go-sql-driver/mysql"
 
@@ -78,6 +79,8 @@ func main() {
 
 	manager.NewManager(cfg, cache.CollectRule).Start(ctx)
 
+	pluginInfo()
+
 	http.Start()
 
 	ending(cancel)
@@ -132,3 +135,10 @@ func ending(cancel context.CancelFunc) {
 	http.Shutdown()
 	fmt.Printf("%s stopped successfully\n", os.Args[0])
 }
+
+func pluginInfo() {
+	fmt.Println("remote collector")
+	for k, v := range collector.GetRemoteCollectors() {
+		fmt.Printf("  %d %s\n", k, v)
+	}
+}