feat: introduce db stats collector

Makefile

@@ -82,6 +82,7 @@ sec: ## Run security checks
 
 .PHONY: fmt
 fmt: install-tools ## Formats all go files
+	$(GO) generate ./...
 	$(GO) run $(govulncheck) ./...
 	$(GO) run $(gofumpt) -l -w -extra  .
 	find . -type f -name '*.go' -exec grep -L -E 'Code generated by .*\. DO NOT EDIT.' {} + | xargs $(GO) run $(goimports) -format-only -w -local=github.com/rudderlabs

go.mod

@@ -73,6 +73,7 @@ require (
 	dario.cat/mergo v1.0.0 // indirect
 	github.com/Azure/azure-pipeline-go v0.2.3 // indirect
 	github.com/Azure/go-ansiterm v0.0.0-20230124172434-306776ec8161 // indirect
+	github.com/DATA-DOG/go-sqlmock v1.5.2
 	github.com/Microsoft/go-winio v0.6.2 // indirect
 	github.com/Nvveen/Gotty v0.0.0-20120604004816-cd527374f1e5 // indirect
 	github.com/actgardner/gogen-avro/v10 v10.2.1 // indirect

go.sum

@@ -43,6 +43,8 @@ github.com/Azure/go-autorest/logger v0.2.1/go.mod h1:T9E3cAhj2VqvPOtCYAvby9aBXkZ
 github.com/Azure/go-autorest/tracing v0.6.0 h1:TYi4+3m5t6K48TGI9AUdb+IzbnSxvnvUMfuitfgcfuo=
 github.com/Azure/go-autorest/tracing v0.6.0/go.mod h1:+vhtPC754Xsa23ID7GlGsrdKBpUA79WCAKPPZVC2DeU=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
+github.com/DATA-DOG/go-sqlmock v1.5.2 h1:OcvFkGmslmlZibjAjaHm3L//6LiuBgolP7OputlJIzU=
+github.com/DATA-DOG/go-sqlmock v1.5.2/go.mod h1:88MAG/4G7SMwSE3CeA0ZKzrT5CiOU3OJ+JlNzwDqpNU=
 github.com/DataDog/zstd v1.5.6 h1:LbEglqepa/ipmmQJUDnSsfvA8e8IStVcGaFWDuxvGOY=
 github.com/DataDog/zstd v1.5.6/go.mod h1:g4AWEaM3yOg3HYfnJ3YIawPnVdXJh9QME85blwSAmyw=
 github.com/Masterminds/semver/v3 v3.2.1 h1:RN9w6+7QoMeJVGyfmbcgs28Br8cvmnucEXnY0rYXWg0=
@@ -320,6 +322,7 @@ github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51 h1:Z9n2FFNU
 github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51/go.mod h1:CzGEWj7cYgsdH8dAjBGEr58BoE7ScuLd+fwFZ44+/x8=
 github.com/kisielk/errcheck v1.5.0/go.mod h1:pFxgyoBC7bSaBwPgfKdkLd5X25qrDl4LWUI2bnpBCr8=
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
+github.com/kisielk/sqlstruct v0.0.0-20201105191214-5f3e10d3ab46/go.mod h1:yyMNCyc/Ib3bDTKd379tNMpB/7/H5TjM2Y9QJ5THLbE=
 github.com/klauspost/compress v1.15.9/go.mod h1:PhcZ0MbTNciWF3rruxRgKxI5NkcHHrHUDtV4Yw2GlzU=
 github.com/klauspost/compress v1.17.10 h1:oXAz+Vh0PMUvJczoi+flxpnBEPxoER1IaAnU/NMPtT0=
 github.com/klauspost/compress v1.17.10/go.mod h1:pMDklpSncoRMuLFrf1W9Ss9KT+0rH90U12bZKk7uwG0=

stats/collectors.go

@@ -0,0 +1,77 @@
+package stats
+
+import (
+	"context"
+	"fmt"
+	"sync"
+	"time"
+)
+
+const defaultPauseDur = 10 * time.Second
+
+type gaugeTagsFunc = func(key string, tags Tags, val uint64)
+
+type Collector interface {
+	Collect(gaugeTagsFunc)
+	Zero(gaugeTagsFunc)
+	ID() string
+}
+
+type aggregatedCollector struct {
+	c         map[string]Collector
+	PauseDur  time.Duration
+	gaugeFunc gaugeTagsFunc
+	mu        sync.Mutex
+}
+
+func (p *aggregatedCollector) Add(c Collector) error {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	if p.c == nil {
+		p.c = make(map[string]Collector)
+	}
+
+	if _, ok := p.c[c.ID()]; ok {
+		return fmt.Errorf("collector with ID %s already register", c.ID())
+	}
+
+	p.c[c.ID()] = c
+	return nil
+}
+
+func (p *aggregatedCollector) Run(ctx context.Context) {
+	defer p.allZero()
+	p.allCollect()
+
+	if p.PauseDur <= 0 {
+		p.PauseDur = defaultPauseDur
+	}
+
+	tick := time.NewTicker(p.PauseDur)
+	defer tick.Stop()
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-tick.C:
+			p.allCollect()
+		}
+	}
+}
+
+func (p *aggregatedCollector) allCollect() {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	for _, c := range p.c {
+		c.Collect(p.gaugeFunc)
+	}
+}
+
+func (p *aggregatedCollector) allZero() {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	for _, c := range p.c {
+		c.Zero(p.gaugeFunc)
+	}
+}

stats/collectors/sqldb.go

@@ -0,0 +1,62 @@
+package collectors
+
+import (
+	"database/sql"
+	"fmt"
+
+	"github.com/rudderlabs/rudder-go-kit/stats"
+)
+
+const (
+	uniqName = "database_sql_%s"
+)
+
+type SQLDBStats struct {
+	name string
+	db   *sql.DB
+}
+
+func NewDatabaseSQLStats(name string, db *sql.DB) *SQLDBStats {
+	return &SQLDBStats{
+		name: name,
+		db:   db,
+	}
+}
+
+func (s *SQLDBStats) Collect(gaugeFunc func(key string, tag stats.Tags, val uint64)) {
+	dbStats := s.db.Stats()
+	tags := stats.Tags{"name": s.name}
+
+	gaugeFunc("sql_db_max_open_connections", tags, uint64(dbStats.MaxOpenConnections))
+	gaugeFunc("sql_db_open_connections", tags, uint64(dbStats.OpenConnections))
+	gaugeFunc("sql_db_in_use_connections", tags, uint64(dbStats.InUse))
+	gaugeFunc("sql_db_idle_connections", tags, uint64(dbStats.Idle))
+
+	gaugeFunc("sql_db_wait_count_total", tags, uint64(dbStats.WaitCount))
+	gaugeFunc("sql_db_wait_duration_seconds_total", tags, uint64(dbStats.WaitDuration.Seconds()))
+
+	gaugeFunc("sql_db_max_idle_closed_total", tags, uint64(dbStats.MaxIdleClosed))
+	gaugeFunc("sql_db_max_idle_time_closed_total", tags, uint64(dbStats.MaxIdleTimeClosed))
+	gaugeFunc("sql_db_max_lifetime_closed_total", tags, uint64(dbStats.MaxLifetimeClosed))
+}
+
+func (s *SQLDBStats) Zero(gaugeFunc func(key string, tag stats.Tags, val uint64)) {
+	tags := stats.Tags{"name": s.name}
+
+	gaugeFunc("sql_db_max_open_connections", tags, 0)
+
+	gaugeFunc("sql_db_open_connections", tags, 0)
+	gaugeFunc("sql_db_in_use_connections", tags, 0)
+	gaugeFunc("sql_db_idle_connections", tags, 0)
+
+	gaugeFunc("sql_db_wait_count_total", tags, 0)
+	gaugeFunc("sql_db_wait_duration_seconds_total", tags, 0)
+
+	gaugeFunc("sql_db_max_idle_closed_total", tags, 0)
+	gaugeFunc("sql_db_max_idle_time_closed_total", tags, 0)
+	gaugeFunc("sql_db_max_lifetime_closed_total", tags, 0)
+}
+
+func (s *SQLDBStats) ID() string {
+	return fmt.Sprintf(uniqName, s.name)
+}

stats/collectors/sqldb_test.go

@@ -0,0 +1,80 @@
+package collectors_test
+
+import (
+	"testing"
+
+	"github.com/DATA-DOG/go-sqlmock"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/rudderlabs/rudder-go-kit/stats"
+	"github.com/rudderlabs/rudder-go-kit/stats/collectors"
+	"github.com/rudderlabs/rudder-go-kit/stats/memstats"
+)
+
+func TestSQLDatabase(t *testing.T) {
+	db, _, err := sqlmock.New()
+	if err != nil {
+		t.Fatalf("an error '%s' was not expected when opening a stub database connection", err)
+	}
+	defer db.Close()
+
+	db.SetMaxOpenConns(5)
+
+	m, err := memstats.New()
+	require.NoError(t, err)
+
+	testName := "test_sqlite"
+	s := collectors.NewDatabaseSQLStats(testName, db)
+
+	err = m.RegisterCollector(s)
+	require.NoError(t, err)
+
+	require.Equal(t, []memstats.Metric{
+		{
+			Name:  "sql_db_idle_connections",
+			Tags:  stats.Tags{"name": testName},
+			Value: 1,
+		},
+		{
+			Name:  "sql_db_in_use_connections",
+			Tags:  stats.Tags{"name": testName},
+			Value: 0,
+		},
+		{
+			Name:  "sql_db_max_idle_closed_total",
+			Tags:  stats.Tags{"name": testName},
+			Value: 0,
+		},
+		{
+			Name:  "sql_db_max_idle_time_closed_total",
+			Tags:  stats.Tags{"name": testName},
+			Value: 0,
+		},
+		{
+			Name:  "sql_db_max_lifetime_closed_total",
+			Tags:  stats.Tags{"name": testName},
+			Value: 0,
+		},
+		{
+			Name:  "sql_db_max_open_connections",
+			Tags:  stats.Tags{"name": testName},
+			Value: 5,
+		},
+		{
+			Name:  "sql_db_open_connections",
+			Tags:  stats.Tags{"name": testName},
+			Value: 1,
+		},
+		{
+			Name:  "sql_db_wait_count_total",
+			Tags:  stats.Tags{"name": testName},
+			Value: 0,
+		},
+		{
+			Name:  "sql_db_wait_duration_seconds_total",
+			Tags:  stats.Tags{"name": testName},
+			Value: 0,
+		},
+	}, m.GetAll())
+}

stats/collectors/static.go

@@ -0,0 +1,39 @@
+package collectors
+
+import (
+	"fmt"
+
+	"github.com/rudderlabs/rudder-go-kit/stats"
+)
+
+const (
+	statsUniqName = "static_%s_%s"
+)
+
+type staticStats struct {
+	tags  stats.Tags
+	key   string
+	value uint64
+}
+
+// NewStaticMetric allows to capture a gauge metric that does not change during the lifetime of the application.
+// Can be useful for capturing configuration values or application version.
+func NewStaticMetric(key string, tags stats.Tags, value uint64) *staticStats {
+	return &staticStats{
+		tags:  tags,
+		key:   key,
+		value: value,
+	}
+}
+
+func (s *staticStats) Collect(gaugeFunc func(key string, tag stats.Tags, val uint64)) {
+	gaugeFunc(s.key, s.tags, s.value)
+}
+
+func (s *staticStats) Zero(gaugeFunc func(key string, tag stats.Tags, val uint64)) {
+	gaugeFunc(s.key, s.tags, 0)
+}
+
+func (s *staticStats) ID() string {
+	return fmt.Sprintf(statsUniqName, s.key, s.tags.String())
+}

stats/collectors/static_test.go

@@ -0,0 +1,32 @@
+package collectors_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/rudderlabs/rudder-go-kit/stats"
+	"github.com/rudderlabs/rudder-go-kit/stats/collectors"
+	"github.com/rudderlabs/rudder-go-kit/stats/memstats"
+)
+
+func TestStatic(t *testing.T) {
+	testName := "test_sqlite"
+	s := collectors.NewStaticMetric(testName, stats.Tags{
+		"foo": "bar",
+	}, 2)
+
+	m, err := memstats.New()
+	require.NoError(t, err)
+
+	err = m.RegisterCollector(s)
+	require.NoError(t, err)
+
+	require.Equal(t, []memstats.Metric{
+		{
+			Name:  testName,
+			Tags:  stats.Tags{"foo": "bar"},
+			Value: 2,
+		},
+	}, m.GetAll())
+}

stats/memstats/stats.go

@@ -354,6 +354,13 @@ func (*Store) Start(_ context.Context, _ stats.GoRoutineFactory) error { return
 // Stop implements stats.Stats
 func (*Store) Stop() {}
 
+func (s *Store) RegisterCollector(c stats.Collector) error {
+	c.Collect(func(key string, tags stats.Tags, val uint64) {
+		s.NewTaggedStat(key, stats.GaugeType, tags).Gauge(val)
+	})
+	return nil
+}
+
 // getKey maps name and tags, to a store lookup key.
 func (*Store) getKey(name string, tags stats.Tags) string {
 	return name + tags.String()

stats/nop.go

@@ -39,3 +39,5 @@ func (*nop) NewTracer(_ string) Tracer {
 
 func (*nop) Start(_ context.Context, _ GoRoutineFactory) error { return nil }
 func (*nop) Stop()                                             {}
+
+func (*nop) RegisterCollector(c Collector) error { return nil }