Add uptime_ns field to mongodb input (#6669)

plugins/inputs/mongodb/README.md

@@ -74,7 +74,7 @@ by running Telegraf with the `--debug` argument.
     - flushes (integer)
     - flushes_total_time_ns (integer)
     - getmores (integer)
-    - inserts (integer
+    - inserts (integer)
     - jumbo_chunks (integer)
     - member_status (string)
     - net_in_bytes_count (integer)
@@ -102,6 +102,7 @@ by running Telegraf with the `--debug` argument.
     - ttl_deletes (integer)
     - ttl_passes (integer)
     - updates (integer)
+    - uptime_ns (integer)
     - vsize_megabytes (integer)
     - wtcache_app_threads_page_read_count (integer)
     - wtcache_app_threads_page_read_time (integer)

plugins/inputs/mongodb/mongodb_data.go

@@ -38,6 +38,7 @@ func NewMongodbData(statLine *StatLine, tags map[string]string) *MongodbData {
 }
 
 var DefaultStats = map[string]string{
+	"uptime_ns":                 "UptimeNanos",
 	"inserts":                   "InsertCnt",
 	"inserts_per_sec":           "Insert",
 	"queries":                   "QueryCnt",

plugins/inputs/mongodb/mongodb_data_test.go

@@ -16,6 +16,7 @@ func TestAddNonReplStats(t *testing.T) {
 		&StatLine{
 			StorageEngine:    "",
 			Time:             time.Now(),
+			UptimeNanos:      0,
 			Insert:           0,
 			Query:            0,
 			Update:           0,
@@ -235,6 +236,7 @@ func TestStateTag(t *testing.T) {
 		"resident_megabytes":        int64(0),
 		"updates":                   int64(0),
 		"updates_per_sec":           int64(0),
+		"uptime_ns":                 int64(0),
 		"vsize_megabytes":           int64(0),
 		"ttl_deletes":               int64(0),
 		"ttl_deletes_per_sec":       int64(0),

plugins/inputs/mongodb/mongostat.go

@@ -477,6 +477,8 @@ type StatLine struct {
 	IsMongos bool
 	Host     string
 
+	UptimeNanos int64
+
 	// The time at which this StatLine was generated.
 	Time time.Time
 
@@ -659,6 +661,8 @@ func NewStatLine(oldMongo, newMongo MongoStatus, key string, all bool, sampleSec
 		Faults:    -1,
 	}
 
+	returnVal.UptimeNanos = 1000 * 1000 * newStat.UptimeMillis
+
 	// set connection info
 	returnVal.CurrentC = newStat.Connections.Current
 	returnVal.AvailableC = newStat.Connections.Available