Add cursor metrics to mongodb input (#4114)

plugins/inputs/mongodb/README.md

@@ -48,6 +48,10 @@ Error in input [mongodb]: not authorized on admin to execute command { serverSta
     - active_reads (integer)
     - active_writes (integer)
     - commands_per_sec (integer)
+    - cursor_timed_out (integer)
+    - cursor_no_timeout (integer)
+    - cursor_pinned (integer)
+    - cursor_total (integer)
     - deletes_per_sec (integer)
     - flushes_per_sec (integer)
     - getmores_per_sec (integer)
@@ -120,7 +124,7 @@ Error in input [mongodb]: not authorized on admin to execute command { serverSta
 
 ### Example Output:
 ```
-mongodb,hostname=127.0.0.1:27017 active_reads=0i,active_writes=0i,commands_per_sec=6i,deletes_per_sec=0i,flushes_per_sec=0i,getmores_per_sec=1i,inserts_per_sec=0i,jumbo_chunks=0i,member_status="PRI",net_in_bytes=851i,net_out_bytes=23904i,open_connections=6i,percent_cache_dirty=0,percent_cache_used=0,queries_per_sec=2i,queued_reads=0i,queued_writes=0i,repl_commands_per_sec=0i,repl_deletes_per_sec=0i,repl_getmores_per_sec=0i,repl_inserts_per_sec=0i,repl_lag=0i,repl_queries_per_sec=0i,repl_updates_per_sec=0i,resident_megabytes=67i,state="PRIMARY",total_available=0i,total_created=0i,total_in_use=0i,total_refreshing=0i,ttl_deletes_per_sec=0i,ttl_passes_per_sec=0i,updates_per_sec=0i,vsize_megabytes=729i,wtcache_app_threads_page_read_count=4i,wtcache_app_threads_page_read_time=18i,wtcache_app_threads_page_write_count=6i,wtcache_bytes_read_into=10075i,wtcache_bytes_written_from=115711i,wtcache_current_bytes=86038i,wtcache_max_bytes_configured=1073741824i,wtcache_pages_evicted_by_app_thread=0i,wtcache_pages_queued_for_eviction=0i,wtcache_server_evicting_pages=0i,wtcache_tracked_dirty_bytes=0i,wtcache_worker_thread_evictingpages=0i 1522798796000000000
+mongodb,hostname=127.0.0.1:27017 active_reads=0i,active_writes=0i,commands_per_sec=6i,cursor_no_timeout=0i,cursor_pinned=0i,cursor_timed_out=0i,cursor_total=0i,deletes_per_sec=0i,flushes_per_sec=0i,getmores_per_sec=1i,inserts_per_sec=0i,jumbo_chunks=0i,member_status="PRI",net_in_bytes=851i,net_out_bytes=23904i,open_connections=6i,percent_cache_dirty=0,percent_cache_used=0,queries_per_sec=2i,queued_reads=0i,queued_writes=0i,repl_commands_per_sec=0i,repl_deletes_per_sec=0i,repl_getmores_per_sec=0i,repl_inserts_per_sec=0i,repl_lag=0i,repl_queries_per_sec=0i,repl_updates_per_sec=0i,resident_megabytes=67i,state="PRIMARY",total_available=0i,total_created=0i,total_in_use=0i,total_refreshing=0i,ttl_deletes_per_sec=0i,ttl_passes_per_sec=0i,updates_per_sec=0i,vsize_megabytes=729i,wtcache_app_threads_page_read_count=4i,wtcache_app_threads_page_read_time=18i,wtcache_app_threads_page_write_count=6i,wtcache_bytes_read_into=10075i,wtcache_bytes_written_from=115711i,wtcache_current_bytes=86038i,wtcache_max_bytes_configured=1073741824i,wtcache_pages_evicted_by_app_thread=0i,wtcache_pages_queued_for_eviction=0i,wtcache_server_evicting_pages=0i,wtcache_tracked_dirty_bytes=0i,wtcache_worker_thread_evictingpages=0i 1522798796000000000
 mongodb_db_stats,db_name=local,hostname=127.0.0.1:27017 avg_obj_size=818.625,collections=5i,data_size=6549i,index_size=86016i,indexes=4i,num_extents=0i,objects=8i,ok=1i,storage_size=118784i,type="db_stat" 1522799074000000000
 mongodb_shard_stats,hostname=127.0.0.1:27017,in_use=3i,available=3i,created=4i,refreshing=0i 1522799074000000000
 ```

plugins/inputs/mongodb/mongodb_data.go

@@ -49,6 +49,10 @@ var DefaultStats = map[string]string{
 	"open_connections":    "NumConnections",
 	"ttl_deletes_per_sec": "DeletedDocuments",
 	"ttl_passes_per_sec":  "Passes",
+	"cursor_timed_out":    "TimedOutC",
+	"cursor_no_timeout":   "NoTimeoutC",
+	"cursor_pinned":       "PinnedC",
+	"cursor_total":        "TotalC",
 }
 
 var DefaultReplStats = map[string]string{

plugins/inputs/mongodb/mongodb_data_test.go

@@ -34,6 +34,10 @@ func TestAddNonReplStats(t *testing.T) {
 			NumConnections:   0,
 			Passes:           0,
 			DeletedDocuments: 0,
+			TimedOutC:        0,
+			NoTimeoutC:       0,
+			PinnedC:          0,
+			TotalC:           0,
 		},
 		tags,
 	)
@@ -211,6 +215,10 @@ func TestStateTag(t *testing.T) {
 		"total_available":       int64(0),
 		"total_created":         int64(0),
 		"total_refreshing":      int64(0),
+		"cursor_timed_out":      int64(0),
+		"cursor_no_timeout":     int64(0),
+		"cursor_pinned":         int64(0),
+		"cursor_total":          int64(0),
 	}
 	acc.AssertContainsTaggedFields(t, "mongodb", fields, stateTags)
 }

plugins/inputs/mongodb/mongostat.go

@@ -290,6 +290,7 @@ type OpcountStats struct {
 // MetricsStats stores information related to metrics
 type MetricsStats struct {
 	TTL    *TTLStats    `bson:"ttl"`
+	Cursor *CursorStats `bson:"cursor"`
 }
 
 // TTLStats stores information related to documents with a ttl index.
@@ -298,6 +299,19 @@ type TTLStats struct {
 	Passes           int64 `bson:"passes"`
 }
 
+// CursorStats stores information related to cursor metrics.
+type CursorStats struct {
+	TimedOut int64            `bson:"timedOut"`
+	Open     *OpenCursorStats `bson:"open"`
+}
+
+// OpenCursorStats stores information related to open cursor metrics
+type OpenCursorStats struct {
+	NoTimeout int64 `bson:"noTimeout"`
+	Pinned    int64 `bson:"pinned"`
+	Total     int64 `bson:"total"`
+}
+
 // ReadWriteLockTimes stores time spent holding read/write locks.
 type ReadWriteLockTimes struct {
 	Read       int64 `bson:"R"`
@@ -439,6 +453,10 @@ type StatLine struct {
 	// TTL fields
 	Passes, DeletedDocuments int64
 
+	// Cursor fields
+	TimedOutC                   int64
+	NoTimeoutC, PinnedC, TotalC int64
+
 	// Collection locks (3.0 mmap only)
 	CollectionLocks *CollectionLockStatus
 
@@ -582,10 +600,20 @@ func NewStatLine(oldMongo, newMongo MongoStatus, key string, all bool, sampleSec
 		returnVal.Command = diff(newStat.Opcounters.Command, oldStat.Opcounters.Command, sampleSecs)
 	}
 
-	if newStat.Metrics != nil && newStat.Metrics.TTL != nil && oldStat.Metrics != nil && oldStat.Metrics.TTL != nil {
+	if newStat.Metrics != nil && oldStat.Metrics != nil {
+		if newStat.Metrics.TTL != nil && oldStat.Metrics.TTL != nil {
 			returnVal.Passes = diff(newStat.Metrics.TTL.Passes, oldStat.Metrics.TTL.Passes, sampleSecs)
 			returnVal.DeletedDocuments = diff(newStat.Metrics.TTL.DeletedDocuments, oldStat.Metrics.TTL.DeletedDocuments, sampleSecs)
 		}
+		if newStat.Metrics.Cursor != nil && oldStat.Metrics.Cursor != nil {
+			returnVal.TimedOutC = diff(newStat.Metrics.Cursor.TimedOut, oldStat.Metrics.Cursor.TimedOut, sampleSecs)
+			if newStat.Metrics.Cursor.Open != nil && oldStat.Metrics.Cursor.Open != nil {
+				returnVal.NoTimeoutC = diff(newStat.Metrics.Cursor.Open.NoTimeout, oldStat.Metrics.Cursor.Open.NoTimeout, sampleSecs)
+				returnVal.PinnedC = diff(newStat.Metrics.Cursor.Open.Pinned, oldStat.Metrics.Cursor.Open.Pinned, sampleSecs)
+				returnVal.TotalC = diff(newStat.Metrics.Cursor.Open.Total, oldStat.Metrics.Cursor.Open.Total, sampleSecs)
+			}
+		}
+	}
 
 	if newStat.OpcountersRepl != nil && oldStat.OpcountersRepl != nil {
 		returnVal.InsertR = diff(newStat.OpcountersRepl.Insert, oldStat.OpcountersRepl.Insert, sampleSecs)