From c21f77fd39b199a152caa5a1672f004f9052fd9a Mon Sep 17 00:00:00 2001
From: Daniel Nelson <daniel.nelson@influxdb.com>
Date: Fri, 20 Sep 2019 16:50:19 -0700
Subject: [PATCH] Require goplugin build flag to enable go plugin support
 (#6393)

---
 cmd/telegraf/telegraf.go      | 36 ++----------------------------
 internal/goplugin/noplugin.go |  9 ++++++++
 internal/goplugin/plugin.go   | 42 +++++++++++++++++++++++++++++++++++
 3 files changed, 53 insertions(+), 34 deletions(-)
 create mode 100644 internal/goplugin/noplugin.go
 create mode 100644 internal/goplugin/plugin.go

diff --git a/cmd/telegraf/telegraf.go b/cmd/telegraf/telegraf.go
index 4d4b62759ddaf..f865cee5149c6 100644
--- a/cmd/telegraf/telegraf.go
+++ b/cmd/telegraf/telegraf.go
@@ -10,9 +10,6 @@ import (
 	_ "net/http/pprof" // Comment this line to disable pprof endpoint.
 	"os"
 	"os/signal"
-	"path"
-	"path/filepath"
-	"plugin"
 	"runtime"
 	"strings"
 	"syscall"
@@ -21,6 +18,7 @@ import (
 	"github.com/influxdata/telegraf/agent"
 	"github.com/influxdata/telegraf/internal"
 	"github.com/influxdata/telegraf/internal/config"
+	"github.com/influxdata/telegraf/internal/goplugin"
 	"github.com/influxdata/telegraf/logger"
 	_ "github.com/influxdata/telegraf/plugins/aggregators/all"
 	"github.com/influxdata/telegraf/plugins/inputs"
@@ -116,36 +114,6 @@ func reloadLoop(
 	}
 }
 
-// loadExternalPlugins loads external plugins from shared libraries (.so, .dll, etc.)
-// in the specified directory.
-func loadExternalPlugins(rootDir string) error {
-	return filepath.Walk(rootDir, func(pth string, info os.FileInfo, err error) error {
-		// Stop if there was an error.
-		if err != nil {
-			return err
-		}
-
-		// Ignore directories.
-		if info.IsDir() {
-			return nil
-		}
-
-		// Ignore files that aren't shared libraries.
-		ext := strings.ToLower(path.Ext(pth))
-		if ext != ".so" && ext != ".dll" {
-			return nil
-		}
-
-		// Load plugin.
-		_, err = plugin.Open(pth)
-		if err != nil {
-			return fmt.Errorf("error loading %s: %s", pth, err)
-		}
-
-		return nil
-	})
-}
-
 func runAgent(ctx context.Context,
 	inputFilters []string,
 	outputFilters []string,
@@ -317,7 +285,7 @@ func main() {
 	// Load external plugins, if requested.
 	if *fPlugins != "" {
 		log.Printf("I! Loading external plugins from: %s", *fPlugins)
-		if err := loadExternalPlugins(*fPlugins); err != nil {
+		if err := goplugin.LoadExternalPlugins(*fPlugins); err != nil {
 			log.Fatal("E! " + err.Error())
 		}
 	}
diff --git a/internal/goplugin/noplugin.go b/internal/goplugin/noplugin.go
new file mode 100644
index 0000000000000..23d8634c46520
--- /dev/null
+++ b/internal/goplugin/noplugin.go
@@ -0,0 +1,9 @@
+// +build !goplugin
+
+package goplugin
+
+import "errors"
+
+func LoadExternalPlugins(rootDir string) error {
+	return errors.New("go plugin support is not enabled")
+}
diff --git a/internal/goplugin/plugin.go b/internal/goplugin/plugin.go
new file mode 100644
index 0000000000000..7e58ec32e92c2
--- /dev/null
+++ b/internal/goplugin/plugin.go
@@ -0,0 +1,42 @@
+// +build goplugin
+
+package goplugin
+
+import (
+	"fmt"
+	"os"
+	"path"
+	"path/filepath"
+	"plugin"
+	"strings"
+)
+
+// loadExternalPlugins loads external plugins from shared libraries (.so, .dll, etc.)
+// in the specified directory.
+func LoadExternalPlugins(rootDir string) error {
+	return filepath.Walk(rootDir, func(pth string, info os.FileInfo, err error) error {
+		// Stop if there was an error.
+		if err != nil {
+			return err
+		}
+
+		// Ignore directories.
+		if info.IsDir() {
+			return nil
+		}
+
+		// Ignore files that aren't shared libraries.
+		ext := strings.ToLower(path.Ext(pth))
+		if ext != ".so" && ext != ".dll" {
+			return nil
+		}
+
+		// Load plugin.
+		_, err = plugin.Open(pth)
+		if err != nil {
+			return fmt.Errorf("error loading %s: %s", pth, err)
+		}
+
+		return nil
+	})
+}