gopls/internal/telemetry: record Go version used in each view

Change-Id: I59233ca205b59726a75791db04dfc1fe8dd4fff4
Reviewed-on: https://go-review.googlesource.com/c/tools/+/515558
Run-TryBot: Hyang-Ah Hana Kim <[email protected]>
Reviewed-by: Jamal Carvalho <[email protected]>
Reviewed-by: Robert Findley <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
gopls-CI: kokoro <[email protected]>

Author: hyangah

gopls/internal/lsp/general.go

@@ -317,6 +317,7 @@ func (s *Server) checkViewGoVersions() {
 		if oldestVersion == -1 || viewVersion < oldestVersion {
 			oldestVersion, fromBuild = viewVersion, false
 		}
+		telemetry.RecordViewGoVersion(viewVersion)
 	}
 
 	if msg, mType := versionMessage(oldestVersion, fromBuild); msg != "" {

gopls/internal/telemetry/telemetry.go

@@ -5,6 +5,7 @@
 package telemetry
 
 import (
+	"fmt"
 	"os"
 
 	"golang.org/x/telemetry/counter"
@@ -50,3 +51,12 @@ func RecordClientInfo(params *protocol.ParamInitialize) {
 	}
 	counter.Inc(client)
 }
+
+// RecordViewGoVersion records the Go minor version number (1.x) used for a view.
+func RecordViewGoVersion(x int) {
+	if x < 0 {
+		return
+	}
+	name := fmt.Sprintf("gopls/goversion:1.%d", x)
+	counter.Inc(name)
+}