replSetGetConfigCollector (#295)

* replSetGetConfigCollector. it just works

* Use member_idx for host field to match with replStatus

* Add --disable.replicasetconfig option flag

* Use errors.As() instead of type assertion.

* Add replset_config_collector_test.

* Revert "Use errors.As() instead of type assertion."

This reverts commit 54ded8c.

* nolint - errors.As seems to cause segfault.

* Update exporter/replset_config_collector.go

* Update exporter/replset_config_collector_test.go

* Update exporter/replset_config_collector.go

* Update exporter/replset_config_collector_test.go

* Update exporter/replset_config_collector.go

* Update exporter/exporter.go

* Update exporter/exporter.go

* Update exporter/replset_config_collector_test.go

* Update replset_config_collector.go

* Update replset_config_collector_test.go

* Update exporter/replset_config_collector_test.go

* Update exporter/replset_config_collector.go

* Update replset_config_collector.go

---------

Co-authored-by: JiriCtvrtka <[email protected]>
Co-authored-by: Denys Kondratenko <[email protected]>
Co-authored-by: Nurlan Moldomurov <[email protected]>
Co-authored-by: Nurlan Moldomurov <[email protected]>

README.md

@@ -14,6 +14,7 @@ Currently, these metric sources are implemented:
 - $indexStats
 - getDiagnosticData
 - replSetGetStatus
+- replSetGetConfig
 - serverStatus
 
 ## Supported MongoDB versions

exporter/exporter.go

@@ -64,6 +64,7 @@ type Opts struct {
 	EnableDBStatsFreeStorage bool
 	EnableDiagnosticData     bool
 	EnableReplicasetStatus   bool
+	EnableReplicasetConfig   bool
 	EnableCurrentopMetrics   bool
 	EnableTopMetrics         bool
 	EnableIndexStats         bool
@@ -163,6 +164,7 @@ func (e *Exporter) makeRegistry(ctx context.Context, client *mongo.Client, topol
 		e.opts.EnableCollStats = true
 		e.opts.EnableTopMetrics = true
 		e.opts.EnableReplicasetStatus = true
+		e.opts.EnableReplicasetConfig = true
 		e.opts.EnableIndexStats = true
 		e.opts.EnableCurrentopMetrics = true
 		e.opts.EnableProfile = true
@@ -239,6 +241,12 @@ func (e *Exporter) makeRegistry(ctx context.Context, client *mongo.Client, topol
 		registry.MustRegister(rsgsc)
 	}
 
+	// replSetGetStatus is not supported through mongos.
+	if e.opts.EnableReplicasetConfig && nodeType != typeMongos && requestOpts.EnableReplicasetConfig {
+		rsgsc := newReplicationSetConfigCollector(ctx, client, e.opts.Logger,
+			e.opts.CompatibleMode, topologyInfo)
+		registry.MustRegister(rsgsc)
+	}
 	if e.opts.EnableShards && nodeType == typeMongos && requestOpts.EnableShards {
 		sc := newShardsCollector(ctx, client, e.opts.Logger, e.opts.CompatibleMode)
 		registry.MustRegister(sc)
@@ -374,6 +382,8 @@ func GetRequestOpts(filters []string, defaultOpts *Opts) Opts {
 			requestOpts.EnableDiagnosticData = true
 		case "replicasetstatus":
 			requestOpts.EnableReplicasetStatus = true
+		case "replicasetconfig":
+			requestOpts.EnableReplicasetConfig = true
 		case "dbstats":
 			requestOpts.EnableDBStats = true
 		case "topmetrics":

exporter/metrics.go

@@ -328,6 +328,9 @@ func processSlice(prefix, k string, v []interface{}, commonLabels map[string]str
 		if state, ok := s["stateStr"].(string); ok {
 			labels["member_state"] = state
 		}
+		if host, ok := s["host"].(string); ok {
+			labels["member_idx"] = host
+		}
 
 		metrics = append(metrics, makeMetrics(prefix+k, s, labels, compatibleMode)...)
 	}

exporter/replset_config_collector.go

@@ -0,0 +1,94 @@
+// mongodb_exporter
+// Copyright (C) 2017 Percona LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package exporter
+
+import (
+	"context"
+
+	"github.com/pkg/errors"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/sirupsen/logrus"
+	"go.mongodb.org/mongo-driver/bson"
+	"go.mongodb.org/mongo-driver/mongo"
+)
+
+type replSetGetConfigCollector struct {
+	ctx  context.Context
+	base *baseCollector
+
+	compatibleMode bool
+	topologyInfo   labelsGetter
+}
+
+// newReplicationSetConfigCollector creates a collector for configuration of replication set.
+func newReplicationSetConfigCollector(ctx context.Context, client *mongo.Client, logger *logrus.Logger, compatible bool, topology labelsGetter) *replSetGetConfigCollector {
+	return &replSetGetConfigCollector{
+		ctx:  ctx,
+		base: newBaseCollector(client, logger.WithFields(logrus.Fields{"collector": "replset_config"})),
+
+		compatibleMode: compatible,
+		topologyInfo:   topology,
+	}
+}
+
+func (d *replSetGetConfigCollector) Describe(ch chan<- *prometheus.Desc) {
+	d.base.Describe(d.ctx, ch, d.collect)
+}
+
+func (d *replSetGetConfigCollector) Collect(ch chan<- prometheus.Metric) {
+	d.base.Collect(ch)
+}
+
+func (d *replSetGetConfigCollector) collect(ch chan<- prometheus.Metric) {
+	defer measureCollectTime(ch, "mongodb", "replset_config")()
+
+	logger := d.base.logger
+	client := d.base.client
+
+	cmd := bson.D{{Key: "replSetGetConfig", Value: "1"}}
+	res := client.Database("admin").RunCommand(d.ctx, cmd)
+
+	var m bson.M
+
+	if err := res.Decode(&m); err != nil {
+		if e, ok := err.(mongo.CommandError); ok { //nolint // https://github.com/percona/mongodb_exporter/pull/295#issuecomment-922874632
+			if e.Code == replicationNotYetInitialized || e.Code == replicationNotEnabled {
+				return
+			}
+		}
+		logger.Errorf("cannot get replSetGetConfig: %s", err)
+
+		return
+	}
+
+	config, ok := m["config"].(bson.M)
+	if !ok {
+		err := errors.Wrapf(errUnexpectedDataType, "%T for data field", m["config"])
+		logger.Errorf("cannot decode getDiagnosticData: %s", err)
+
+		return
+	}
+	m = config
+
+	logger.Debug("replSetGetConfig result:")
+	debugResult(logger, m)
+
+	for _, metric := range makeMetrics("rs_cfg", m, d.topologyInfo.baseLabels(), d.compatibleMode) {
+		ch <- metric
+	}
+}
+
+var _ prometheus.Collector = (*replSetGetConfigCollector)(nil)

exporter/replset_config_collector_test.go

@@ -0,0 +1,72 @@
+// mongodb_exporter
+// Copyright (C) 2017 Percona LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package exporter
+
+import (
+	"context"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus/testutil"
+	"github.com/sirupsen/logrus"
+	"github.com/stretchr/testify/assert"
+
+	"github.com/percona/mongodb_exporter/internal/tu"
+)
+
+func TestReplsetConfigCollector(t *testing.T) {
+	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
+	defer cancel()
+
+	client := tu.DefaultTestClient(ctx, t)
+
+	ti := labelsGetterMock{}
+
+	c := newReplicationSetConfigCollector(ctx, client, logrus.New(), false, ti)
+
+	// The last \n at the end of this string is important
+	expected := strings.NewReader(`
+	# HELP mongodb_rs_cfg_protocolVersion rs_cfg.
+	# TYPE mongodb_rs_cfg_protocolVersion untyped
+	mongodb_rs_cfg_protocolVersion 1` + "\n")
+	// Filter metrics for 2 reasons:
+	// 1. The result is huge
+	// 2. We need to check against know values. Don't use metrics that return counters like uptime
+	//    or counters like the number of transactions because they won't return a known value to compare
+	filter := []string{
+		"mongodb_rs_cfg_protocolVersion",
+	}
+	err := testutil.CollectAndCompare(c, expected, filter...)
+	assert.NoError(t, err)
+}
+
+func TestReplsetConfigCollectorNoSharding(t *testing.T) {
+	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
+	defer cancel()
+
+	client := tu.TestClient(ctx, tu.MongoDBStandAlonePort, t)
+
+	ti := labelsGetterMock{}
+
+	c := newReplicationSetConfigCollector(ctx, client, logrus.New(), false, ti)
+
+	// Replication set metrics should not be generated for unsharded server
+	count := testutil.CollectAndCount(c)
+
+	metaMetricCount := 1
+	assert.Equal(t, metaMetricCount, count, "Mismatch in metric count for collector run on unsharded server")
+}

main.go

@@ -54,6 +54,7 @@ type GlobalFlags struct {
 	EnableExporterMetrics    bool `name:"collector.exporter-metrics" help:"Enable collecting metrics about the exporter itself (process_*, go_*)" negatable:"" default:"True"`
 	EnableDiagnosticData     bool `name:"collector.diagnosticdata" help:"Enable collecting metrics from getDiagnosticData"`
 	EnableReplicasetStatus   bool `name:"collector.replicasetstatus" help:"Enable collecting metrics from replSetGetStatus"`
+	EnableReplicasetConfig   bool `name:"collector.replicasetconfig" help:"Enable collecting metrics from replSetGetConfig"`
 	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"`
@@ -166,6 +167,7 @@ func buildExporter(opts GlobalFlags, uri string, log *logrus.Logger) *exporter.E
 		DisableDefaultRegistry:   !opts.EnableExporterMetrics,
 		EnableDiagnosticData:     opts.EnableDiagnosticData,
 		EnableReplicasetStatus:   opts.EnableReplicasetStatus,
+		EnableReplicasetConfig:   opts.EnableReplicasetConfig,
 		EnableCurrentopMetrics:   opts.EnableCurrentopMetrics,
 		EnableTopMetrics:         opts.EnableTopMetrics,
 		EnableDBStats:            opts.EnableDBStats,

main_test.go

@@ -112,6 +112,7 @@ func TestBuildExporter(t *testing.T) {
 
 		EnableDiagnosticData:   true,
 		EnableReplicasetStatus: true,
+		EnableReplicasetConfig: true,
 
 		CompatibleMode: true,
 	}