From 7bb219222a6fdc26954f5a1f05991730f377a718 Mon Sep 17 00:00:00 2001
From: Kevin Conaway <kevin.a.conaway@gmail.com>
Date: Tue, 9 Oct 2018 16:45:07 -0400
Subject: [PATCH] Add internal function for telegraf version (#4828)

---
 cmd/telegraf/telegraf.go  | 10 ++++++++++
 internal/internal.go      | 19 +++++++++++++++++++
 internal/internal_test.go | 12 ++++++++++++
 3 files changed, 41 insertions(+)

diff --git a/cmd/telegraf/telegraf.go b/cmd/telegraf/telegraf.go
index 93336ffb4..02f22353b 100644
--- a/cmd/telegraf/telegraf.go
+++ b/cmd/telegraf/telegraf.go
@@ -326,6 +326,16 @@ func main() {
 		return
 	}
 
+	shortVersion := version
+	if shortVersion == "" {
+		shortVersion = "unknown"
+	}
+
+	// Configure version
+	if err := internal.SetVersion(shortVersion); err != nil {
+		log.Println("Telegraf version already configured to: " + internal.Version())
+	}
+
 	if runtime.GOOS == "windows" && !(*fRunAsConsole) {
 		svcConfig := &service.Config{
 			Name:        *fServiceName,
diff --git a/internal/internal.go b/internal/internal.go
index 6d087cceb..f6b85de84 100644
--- a/internal/internal.go
+++ b/internal/internal.go
@@ -24,13 +24,32 @@ var (
 	TimeoutErr = errors.New("Command timed out.")
 
 	NotImplementedError = errors.New("not implemented yet")
+
+	VersionAlreadySetError = errors.New("version has already been set")
 )
 
+// Set via the main module
+var version string
+
 // Duration just wraps time.Duration
 type Duration struct {
 	Duration time.Duration
 }
 
+// SetVersion sets the telegraf agent version
+func SetVersion(v string) error {
+	if version != "" {
+		return VersionAlreadySetError
+	}
+	version = v
+	return nil
+}
+
+// Version returns the telegraf agent version
+func Version() string {
+	return version
+}
+
 // UnmarshalTOML parses the duration from the TOML config file
 func (d *Duration) UnmarshalTOML(b []byte) error {
 	var err error
diff --git a/internal/internal_test.go b/internal/internal_test.go
index 3b4ec5dda..486c3d744 100644
--- a/internal/internal_test.go
+++ b/internal/internal_test.go
@@ -182,3 +182,15 @@ func TestCompressWithGzip(t *testing.T) {
 
 	assert.Equal(t, testData, string(output))
 }
+
+func TestVersionAlreadySet(t *testing.T) {
+	err := SetVersion("foo")
+	assert.Nil(t, err)
+
+	err = SetVersion("bar")
+
+	assert.NotNil(t, err)
+	assert.IsType(t, VersionAlreadySetError, err)
+
+	assert.Equal(t, "foo", Version())
+}