add option --collector.dbstatsfreestorage to receive freeStorage stats from dbstats (#666)

* add option --collector.dbstatsfreestorage to receive freeStorage stats from dbstats #617

* do not add freeStorage option per default. not suppored at mongodb 4.4

---------

Co-authored-by: Alex Tymchuk <[email protected]>
Co-authored-by: Nurlan Moldomurov <[email protected]>

Author: 3 people

exporter/dbstats_collector.go

@@ -32,10 +32,12 @@ type dbstatsCollector struct {
 	topologyInfo   labelsGetter
 
 	databaseFilter []string
+
+	freeStorage bool
 }
 
 // newDBStatsCollector creates a collector for statistics on database storage.
-func newDBStatsCollector(ctx context.Context, client *mongo.Client, logger *logrus.Logger, compatible bool, topology labelsGetter, databaseRegex []string) *dbstatsCollector {
+func newDBStatsCollector(ctx context.Context, client *mongo.Client, logger *logrus.Logger, compatible bool, topology labelsGetter, databaseRegex []string, freeStorage bool) *dbstatsCollector {
 	return &dbstatsCollector{
 		ctx:  ctx,
 		base: newBaseCollector(client, logger),
@@ -44,6 +46,8 @@ func newDBStatsCollector(ctx context.Context, client *mongo.Client, logger *logr
 		topologyInfo:   topology,
 
 		databaseFilter: databaseRegex,
+
+		freeStorage: freeStorage,
 	}
 }
 
@@ -71,7 +75,12 @@ func (d *dbstatsCollector) collect(ch chan<- prometheus.Metric) {
 	logger.Debugf("getting stats for databases: %v", dbNames)
 	for _, db := range dbNames {
 		var dbStats bson.M
-		cmd := bson.D{{Key: "dbStats", Value: 1}, {Key: "scale", Value: 1}}
+		var cmd bson.D
+		if d.freeStorage {
+			cmd = bson.D{{Key: "dbStats", Value: 1}, {Key: "scale", Value: 1}, {Key: "freeStorage", Value: 1}}
+		} else {
+			cmd = bson.D{{Key: "dbStats", Value: 1}, {Key: "scale", Value: 1}}
+		}
 		r := client.Database(db).RunCommand(d.ctx, cmd)
 		err := r.Decode(&dbStats)
 		if err != nil {

exporter/dbstats_collector_test.go

@@ -58,7 +58,7 @@ func TestDBStatsCollector(t *testing.T) {
 
 	ti := labelsGetterMock{}
 
-	c := newDBStatsCollector(ctx, client, logrus.New(), false, ti, []string{dbName})
+	c := newDBStatsCollector(ctx, client, logrus.New(), false, ti, []string{dbName}, false)
 	expected := strings.NewReader(`
 	# HELP mongodb_dbstats_collections dbstats.
 	# TYPE mongodb_dbstats_collections untyped

exporter/exporter.go

@@ -60,13 +60,14 @@ type Opts struct {
 	DiscoveringMode        bool
 	GlobalConnPool         bool
 
-	CollectAll             bool
-	EnableDBStats          bool
-	EnableDiagnosticData   bool
-	EnableReplicasetStatus bool
-	EnableTopMetrics       bool
-	EnableIndexStats       bool
-	EnableCollStats        bool
+	CollectAll               bool
+	EnableDBStats            bool
+	EnableDBStatsFreeStorage bool
+	EnableDiagnosticData     bool
+	EnableReplicasetStatus   bool
+	EnableTopMetrics         bool
+	EnableIndexStats         bool
+	EnableCollStats          bool
 
 	EnableOverrideDescendingIndex bool
 
@@ -164,6 +165,7 @@ func (e *Exporter) makeRegistry(ctx context.Context, client *mongo.Client, topol
 		}
 		e.opts.EnableDiagnosticData = true
 		e.opts.EnableDBStats = true
+		e.opts.EnableDBStatsFreeStorage = true
 		e.opts.EnableCollStats = true
 		e.opts.EnableTopMetrics = true
 		e.opts.EnableReplicasetStatus = true
@@ -173,6 +175,7 @@ func (e *Exporter) makeRegistry(ctx context.Context, client *mongo.Client, topol
 	// arbiter only have isMaster privileges
 	if isArbiter {
 		e.opts.EnableDBStats = false
+		e.opts.EnableDBStatsFreeStorage = false
 		e.opts.EnableCollStats = false
 		e.opts.EnableTopMetrics = false
 		e.opts.EnableReplicasetStatus = false
@@ -203,7 +206,7 @@ func (e *Exporter) makeRegistry(ctx context.Context, client *mongo.Client, topol
 
 	if e.opts.EnableDBStats && limitsOk && requestOpts.EnableDBStats {
 		cc := newDBStatsCollector(ctx, client, e.opts.Logger,
-			e.opts.CompatibleMode, topologyInfo, nil)
+			e.opts.CompatibleMode, topologyInfo, nil, e.opts.EnableDBStatsFreeStorage)
 		registry.MustRegister(cc)
 	}
 

main.go

@@ -44,12 +44,13 @@ type GlobalFlags struct {
 	TLSConfigPath         string `name:"web.config" help:"Path to the file having Prometheus TLS config for basic auth"`
 	LogLevel              string `name:"log.level" help:"Only log messages with the given severity or above. Valid levels: [debug, info, warn, error, fatal]" enum:"debug,info,warn,error,fatal" default:"error"`
 
-	EnableDiagnosticData   bool `name:"collector.diagnosticdata" help:"Enable collecting metrics from getDiagnosticData"`
-	EnableReplicasetStatus bool `name:"collector.replicasetstatus" help:"Enable collecting metrics from replSetGetStatus"`
-	EnableDBStats          bool `name:"collector.dbstats" help:"Enable collecting metrics from dbStats"`
-	EnableTopMetrics       bool `name:"collector.topmetrics" help:"Enable collecting metrics from top admin command"`
-	EnableIndexStats       bool `name:"collector.indexstats" help:"Enable collecting metrics from $indexStats"`
-	EnableCollStats        bool `name:"collector.collstats" help:"Enable collecting metrics from $collStats"`
+	EnableDiagnosticData     bool `name:"collector.diagnosticdata" help:"Enable collecting metrics from getDiagnosticData"`
+	EnableReplicasetStatus   bool `name:"collector.replicasetstatus" help:"Enable collecting metrics from replSetGetStatus"`
+	EnableDBStats            bool `name:"collector.dbstats" help:"Enable collecting metrics from dbStats"`
+	EnableDBStatsFreeStorage bool `name:"collector.dbstatsfreestorage" help:"Enable collecting free space metrics from dbStats"`
+	EnableTopMetrics         bool `name:"collector.topmetrics" help:"Enable collecting metrics from top admin command"`
+	EnableIndexStats         bool `name:"collector.indexstats" help:"Enable collecting metrics from $indexStats"`
+	EnableCollStats          bool `name:"collector.collstats" help:"Enable collecting metrics from $collStats"`
 
 	EnableOverrideDescendingIndex bool `name:"metrics.overridedescendingindex" help:"Enable descending index name override to replace -1 with _DESC"`
 
@@ -122,12 +123,13 @@ func buildExporter(opts GlobalFlags) *exporter.Exporter {
 		TLSConfigPath:         opts.TLSConfigPath,
 		DirectConnect:         opts.DirectConnect,
 
-		EnableDiagnosticData:   opts.EnableDiagnosticData,
-		EnableReplicasetStatus: opts.EnableReplicasetStatus,
-		EnableTopMetrics:       opts.EnableTopMetrics,
-		EnableDBStats:          opts.EnableDBStats,
-		EnableIndexStats:       opts.EnableIndexStats,
-		EnableCollStats:        opts.EnableCollStats,
+		EnableDiagnosticData:     opts.EnableDiagnosticData,
+		EnableReplicasetStatus:   opts.EnableReplicasetStatus,
+		EnableTopMetrics:         opts.EnableTopMetrics,
+		EnableDBStats:            opts.EnableDBStats,
+		EnableDBStatsFreeStorage: opts.EnableDBStatsFreeStorage,
+		EnableIndexStats:         opts.EnableIndexStats,
+		EnableCollStats:          opts.EnableCollStats,
 
 		EnableOverrideDescendingIndex: opts.EnableOverrideDescendingIndex,