27 files changed, 1631 insertions, 71 deletions

diff --git a/plugins/logger/plugin.go b/plugins/logger/plugin.go
index f05d0ff0..0a8485d9 100644
--- a/plugins/logger/plugin.go
+++ b/plugins/logger/plugin.go
@@ -2,7 +2,7 @@ package logger
 
 import (
 	"github.com/spiral/endure"
-	"github.com/spiral/roadrunner/v2/log"
+	"github.com/spiral/roadrunner/v2/interfaces/log"
 	"github.com/spiral/roadrunner/v2/plugins/config"
 	"go.uber.org/zap"
 )
diff --git a/plugins/logger/tests/plugin.go b/plugins/logger/tests/plugin.go
index 75d2736d..32238f63 100644
--- a/plugins/logger/tests/plugin.go
+++ b/plugins/logger/tests/plugin.go
@@ -2,7 +2,7 @@ package tests
 
 import (
 	"github.com/spiral/errors"
-	"github.com/spiral/roadrunner/v2/log"
+	"github.com/spiral/roadrunner/v2/interfaces/log"
 	"github.com/spiral/roadrunner/v2/plugins/config"
 )
 
diff --git a/plugins/metrics/config.go b/plugins/metrics/config.go
new file mode 100644
index 00000000..933b7eb8
--- /dev/null
+++ b/plugins/metrics/config.go
@@ -0,0 +1,135 @@
+package metrics
+
+import (
+	"fmt"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// Config configures metrics service.
+type Config struct {
+	// Address to listen
+	Address string
+
+	// Collect define application specific metrics.
+	Collect map[string]Collector
+}
+
+type NamedCollector struct {
+	// Name of the collector
+	Name string `json:"name"`
+
+	// Collector structure
+	Collector `json:"collector"`
+}
+
+// CollectorType represents prometheus collector types
+type CollectorType string
+
+const (
+	// Histogram type
+	Histogram CollectorType = "histogram"
+
+	// Gauge type
+	Gauge CollectorType = "gauge"
+
+	// Counter type
+	Counter CollectorType = "counter"
+
+	// Summary type
+	Summary CollectorType = "summary"
+)
+
+// Collector describes single application specific metric.
+type Collector struct {
+	// Namespace of the metric.
+	Namespace string `json:"namespace"`
+	// Subsystem of the metric.
+	Subsystem string `json:"subsystem"`
+	// Collector type (histogram, gauge, counter, summary).
+	Type CollectorType `json:"type"`
+	// Help of collector.
+	Help string `json:"help"`
+	// Labels for vectorized metrics.
+	Labels []string `json:"labels"`
+	// Buckets for histogram metric.
+	Buckets []float64 `json:"buckets"`
+}
+
+// register application specific metrics.
+func (c *Config) getCollectors() (map[string]prometheus.Collector, error) {
+	if c.Collect == nil {
+		return nil, nil
+	}
+
+	collectors := make(map[string]prometheus.Collector)
+
+	for name, m := range c.Collect {
+		var collector prometheus.Collector
+		switch m.Type {
+		case Histogram:
+			opts := prometheus.HistogramOpts{
+				Name:      name,
+				Namespace: m.Namespace,
+				Subsystem: m.Subsystem,
+				Help:      m.Help,
+				Buckets:   m.Buckets,
+			}
+
+			if len(m.Labels) != 0 {
+				collector = prometheus.NewHistogramVec(opts, m.Labels)
+			} else {
+				collector = prometheus.NewHistogram(opts)
+			}
+		case Gauge:
+			opts := prometheus.GaugeOpts{
+				Name:      name,
+				Namespace: m.Namespace,
+				Subsystem: m.Subsystem,
+				Help:      m.Help,
+			}
+
+			if len(m.Labels) != 0 {
+				collector = prometheus.NewGaugeVec(opts, m.Labels)
+			} else {
+				collector = prometheus.NewGauge(opts)
+			}
+		case Counter:
+			opts := prometheus.CounterOpts{
+				Name:      name,
+				Namespace: m.Namespace,
+				Subsystem: m.Subsystem,
+				Help:      m.Help,
+			}
+
+			if len(m.Labels) != 0 {
+				collector = prometheus.NewCounterVec(opts, m.Labels)
+			} else {
+				collector = prometheus.NewCounter(opts)
+			}
+		case Summary:
+			opts := prometheus.SummaryOpts{
+				Name:      name,
+				Namespace: m.Namespace,
+				Subsystem: m.Subsystem,
+				Help:      m.Help,
+			}
+
+			if len(m.Labels) != 0 {
+				collector = prometheus.NewSummaryVec(opts, m.Labels)
+			} else {
+				collector = prometheus.NewSummary(opts)
+			}
+		default:
+			return nil, fmt.Errorf("invalid metric type `%s` for `%s`", m.Type, name)
+		}
+
+		collectors[name] = collector
+	}
+
+	return collectors, nil
+}
+
+func (c *Config) InitDefaults() {
+
+}
diff --git a/plugins/metrics/config_test.go b/plugins/metrics/config_test.go
new file mode 100644
index 00000000..24c8406c
--- /dev/null
+++ b/plugins/metrics/config_test.go
@@ -0,0 +1,87 @@
+package metrics
+
+import (
+	"bytes"
+	"testing"
+
+	json "github.com/json-iterator/go"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_Config_Hydrate_Error1(t *testing.T) {
+	cfg := `{"request": {"From": "Something"}}`
+	c := &Config{}
+	f := new(bytes.Buffer)
+	f.WriteString(cfg)
+
+	err := json.Unmarshal(f.Bytes(), &c)
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func Test_Config_Hydrate_Error2(t *testing.T) {
+	cfg := `{"dir": "/dir/"`
+	c := &Config{}
+
+	f := new(bytes.Buffer)
+	f.WriteString(cfg)
+
+	err := json.Unmarshal(f.Bytes(), &c)
+	assert.Error(t, err)
+}
+
+func Test_Config_Metrics(t *testing.T) {
+	cfg := `{
+"collect":{
+	"metric1":{"type": "gauge"},
+	"metric2":{	"type": "counter"},
+	"metric3":{"type": "summary"},
+	"metric4":{"type": "histogram"}
+}
+}`
+	c := &Config{}
+	f := new(bytes.Buffer)
+	f.WriteString(cfg)
+
+	err := json.Unmarshal(f.Bytes(), &c)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	m, err := c.getCollectors()
+	assert.NoError(t, err)
+
+	assert.IsType(t, prometheus.NewGauge(prometheus.GaugeOpts{}), m["metric1"])
+	assert.IsType(t, prometheus.NewCounter(prometheus.CounterOpts{}), m["metric2"])
+	assert.IsType(t, prometheus.NewSummary(prometheus.SummaryOpts{}), m["metric3"])
+	assert.IsType(t, prometheus.NewHistogram(prometheus.HistogramOpts{}), m["metric4"])
+}
+
+func Test_Config_MetricsVector(t *testing.T) {
+	cfg := `{
+"collect":{
+	"metric1":{"type": "gauge","labels":["label"]},
+	"metric2":{	"type": "counter","labels":["label"]},
+	"metric3":{"type": "summary","labels":["label"]},
+	"metric4":{"type": "histogram","labels":["label"]}
+}
+}`
+	c := &Config{}
+	f := new(bytes.Buffer)
+	f.WriteString(cfg)
+
+	err := json.Unmarshal(f.Bytes(), &c)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	m, err := c.getCollectors()
+	assert.NoError(t, err)
+
+	assert.IsType(t, prometheus.NewGaugeVec(prometheus.GaugeOpts{}, []string{}), m["metric1"])
+	assert.IsType(t, prometheus.NewCounterVec(prometheus.CounterOpts{}, []string{}), m["metric2"])
+	assert.IsType(t, prometheus.NewSummaryVec(prometheus.SummaryOpts{}, []string{}), m["metric3"])
+	assert.IsType(t, prometheus.NewHistogramVec(prometheus.HistogramOpts{}, []string{}), m["metric4"])
+}
diff --git a/plugins/metrics/doc.go b/plugins/metrics/doc.go
new file mode 100644
index 00000000..1abe097a
--- /dev/null
+++ b/plugins/metrics/doc.go
@@ -0,0 +1 @@
+package metrics
diff --git a/plugins/metrics/plugin.go b/plugins/metrics/plugin.go
new file mode 100644
index 00000000..3fd42ee4
--- /dev/null
+++ b/plugins/metrics/plugin.go
@@ -0,0 +1,230 @@
+package metrics
+
+import (
+	"context"
+	"crypto/tls"
+	"net/http"
+	"sync"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"github.com/spiral/endure"
+	"github.com/spiral/errors"
+	"github.com/spiral/roadrunner/v2/interfaces/log"
+	"github.com/spiral/roadrunner/v2/interfaces/metrics"
+	"github.com/spiral/roadrunner/v2/plugins/config"
+	"golang.org/x/sys/cpu"
+)
+
+const (
+	// ID declares public service name.
+	ServiceName = "metrics"
+	// maxHeaderSize declares max header size for prometheus server
+	maxHeaderSize = 1024 * 1024 * 100 // 104MB
+)
+
+type statsProvider struct {
+	collectors []prometheus.Collector
+	name       string
+}
+
+// Plugin to manage application metrics using Prometheus.
+type Plugin struct {
+	cfg        Config
+	log        log.Logger
+	mu         sync.Mutex // all receivers are pointers
+	http       *http.Server
+	collectors sync.Map // all receivers are pointers
+	registry   *prometheus.Registry
+}
+
+// Init service.
+func (m *Plugin) Init(cfg config.Configurer, log log.Logger) error {
+	const op = errors.Op("Metrics Init")
+	err := cfg.UnmarshalKey(ServiceName, &m.cfg)
+	if err != nil {
+		return err
+	}
+
+	// TODO figure out what is Init
+	m.cfg.InitDefaults()
+
+	m.log = log
+	m.registry = prometheus.NewRegistry()
+
+	// Default
+	err = m.registry.Register(prometheus.NewProcessCollector(prometheus.ProcessCollectorOpts{}))
+	if err != nil {
+		return errors.E(op, err)
+	}
+
+	// Default
+	err = m.registry.Register(prometheus.NewGoCollector())
+	if err != nil {
+		return errors.E(op, err)
+	}
+
+	collectors, err := m.cfg.getCollectors()
+	if err != nil {
+		return errors.E(op, err)
+	}
+
+	// Register invocation will be later in the Serve method
+	for k, v := range collectors {
+		m.collectors.Store(k, statsProvider{
+			collectors: []prometheus.Collector{v},
+			name:       k,
+		})
+	}
+	return nil
+}
+
+// Register new prometheus collector.
+func (m *Plugin) Register(c prometheus.Collector) error {
+	return m.registry.Register(c)
+}
+
+// Serve prometheus metrics service.
+func (m *Plugin) Serve() chan error {
+	errCh := make(chan error, 1)
+	m.collectors.Range(func(key, value interface{}) bool {
+		// key - name
+		// value - statsProvider struct
+		c := value.(statsProvider)
+		for _, v := range c.collectors {
+			if err := m.registry.Register(v); err != nil {
+				errCh <- err
+				return false
+			}
+		}
+
+		return true
+	})
+
+	var topCipherSuites []uint16
+	var defaultCipherSuitesTLS13 []uint16
+
+	hasGCMAsmAMD64 := cpu.X86.HasAES && cpu.X86.HasPCLMULQDQ
+	hasGCMAsmARM64 := cpu.ARM64.HasAES && cpu.ARM64.HasPMULL
+	// Keep in sync with crypto/aes/cipher_s390x.go.
+	hasGCMAsmS390X := cpu.S390X.HasAES && cpu.S390X.HasAESCBC && cpu.S390X.HasAESCTR && (cpu.S390X.HasGHASH || cpu.S390X.HasAESGCM)
+
+	hasGCMAsm := hasGCMAsmAMD64 || hasGCMAsmARM64 || hasGCMAsmS390X
+
+	if hasGCMAsm {
+		// If AES-GCM hardware is provided then prioritise AES-GCM
+		// cipher suites.
+		topCipherSuites = []uint16{
+			tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+			tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+			tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+			tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
+			tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
+			tls.TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,
+		}
+		defaultCipherSuitesTLS13 = []uint16{
+			tls.TLS_AES_128_GCM_SHA256,
+			tls.TLS_CHACHA20_POLY1305_SHA256,
+			tls.TLS_AES_256_GCM_SHA384,
+		}
+	} else {
+		// Without AES-GCM hardware, we put the ChaCha20-Poly1305
+		// cipher suites first.
+		topCipherSuites = []uint16{
+			tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
+			tls.TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,
+			tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+			tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+			tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+			tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
+		}
+		defaultCipherSuitesTLS13 = []uint16{
+			tls.TLS_CHACHA20_POLY1305_SHA256,
+			tls.TLS_AES_128_GCM_SHA256,
+			tls.TLS_AES_256_GCM_SHA384,
+		}
+	}
+
+	DefaultCipherSuites := make([]uint16, 0, 22)
+	DefaultCipherSuites = append(DefaultCipherSuites, topCipherSuites...)
+	DefaultCipherSuites = append(DefaultCipherSuites, defaultCipherSuitesTLS13...)
+
+	m.http = &http.Server{
+		Addr:              m.cfg.Address,
+		Handler:           promhttp.HandlerFor(m.registry, promhttp.HandlerOpts{}),
+		IdleTimeout:       time.Hour * 24,
+		ReadTimeout:       time.Minute * 60,
+		MaxHeaderBytes:    maxHeaderSize,
+		ReadHeaderTimeout: time.Minute * 60,
+		WriteTimeout:      time.Minute * 60,
+		TLSConfig: &tls.Config{
+			CurvePreferences: []tls.CurveID{
+				tls.CurveP256,
+				tls.CurveP384,
+				tls.CurveP521,
+				tls.X25519,
+			},
+			CipherSuites:             DefaultCipherSuites,
+			MinVersion:               tls.VersionTLS12,
+			PreferServerCipherSuites: true,
+		},
+	}
+
+	go func() {
+		err := m.http.ListenAndServe()
+		if err != nil && err != http.ErrServerClosed {
+			errCh <- err
+			return
+		}
+	}()
+
+	return errCh
+}
+
+// Stop prometheus metrics service.
+func (m *Plugin) Stop() error {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	if m.http != nil {
+		// timeout is 10 seconds
+		ctx, cancel := context.WithTimeout(context.Background(), time.Second*10)
+		defer cancel()
+		err := m.http.Shutdown(ctx)
+		if err != nil {
+			// Function should be Stop() error
+			m.log.Error("stop error", "error", errors.Errorf("error shutting down the metrics server: error %v", err))
+		}
+	}
+	return nil
+}
+
+// Collects used to collect all plugins which implement metrics.StatProvider interface (and Named)
+func (m *Plugin) Collects() []interface{} {
+	return []interface{}{
+		m.AddStatProvider,
+	}
+}
+
+// Collector returns application specific collector by name or nil if collector not found.
+func (m *Plugin) AddStatProvider(name endure.Named, stat metrics.StatProvider) error {
+	m.collectors.Store(name.Name(), statsProvider{
+		collectors: stat.MetricsCollector(),
+		name:       name.Name(),
+	})
+	return nil
+}
+
+// RPC interface satisfaction
+func (m *Plugin) Name() string {
+	return ServiceName
+}
+
+// RPC interface satisfaction
+func (m *Plugin) RPC() interface{} {
+	return &rpcServer{
+		svc: m,
+		log: m.log,
+	}
+}
diff --git a/plugins/metrics/rpc.go b/plugins/metrics/rpc.go
new file mode 100644
index 00000000..b8897098
--- /dev/null
+++ b/plugins/metrics/rpc.go
@@ -0,0 +1,294 @@
+package metrics
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/spiral/errors"
+	"github.com/spiral/roadrunner/v2/interfaces/log"
+)
+
+type rpcServer struct {
+	svc *Plugin
+	log log.Logger
+}
+
+// Metric represent single metric produced by the application.
+type Metric struct {
+	// Collector name.
+	Name string
+
+	// Collector value.
+	Value float64
+
+	// Labels associated with metric. Only for vector metrics. Must be provided in a form of label values.
+	Labels []string
+}
+
+// Add new metric to the designated collector.
+func (rpc *rpcServer) Add(m *Metric, ok *bool) error {
+	const op = errors.Op("Add metric")
+	rpc.log.Info("Adding metric", "name", m.Name, "value", m.Value, "labels", m.Labels)
+	c, exist := rpc.svc.collectors.Load(m.Name)
+	if !exist {
+		rpc.log.Error("undefined collector", "collector", m.Name)
+		return errors.E(op, errors.Errorf("undefined collector %s, try first Declare the desired collector", m.Name))
+	}
+
+	switch c := c.(type) {
+	case prometheus.Gauge:
+		c.Add(m.Value)
+
+	case *prometheus.GaugeVec:
+		if len(m.Labels) == 0 {
+			rpc.log.Error("required labels for collector", "collector", m.Name)
+			return errors.E(op, errors.Errorf("required labels for collector %s", m.Name))
+		}
+
+		gauge, err := c.GetMetricWithLabelValues(m.Labels...)
+		if err != nil {
+			rpc.log.Error("failed to get metrics with label values", "collector", m.Name, "labels", m.Labels)
+			return errors.E(op, err)
+		}
+		gauge.Add(m.Value)
+	case prometheus.Counter:
+		c.Add(m.Value)
+
+	case *prometheus.CounterVec:
+		if len(m.Labels) == 0 {
+			return errors.E(op, errors.Errorf("required labels for collector `%s`", m.Name))
+		}
+
+		gauge, err := c.GetMetricWithLabelValues(m.Labels...)
+		if err != nil {
+			rpc.log.Error("failed to get metrics with label values", "collector", m.Name, "labels", m.Labels)
+			return errors.E(op, err)
+		}
+		gauge.Add(m.Value)
+
+	default:
+		return errors.E(op, errors.Errorf("collector %s does not support method `Add`", m.Name))
+	}
+
+	// RPC, set ok to true as return value. Need by rpc.Call reply argument
+	*ok = true
+	rpc.log.Info("new metric successfully added", "name", m.Name, "labels", m.Labels, "value", m.Value)
+	return nil
+}
+
+// Sub subtract the value from the specific metric (gauge only).
+func (rpc *rpcServer) Sub(m *Metric, ok *bool) error {
+	const op = errors.Op("Subtracting metric")
+	rpc.log.Info("Subtracting value from metric", "name", m.Name, "value", m.Value, "labels", m.Labels)
+	c, exist := rpc.svc.collectors.Load(m.Name)
+	if !exist {
+		rpc.log.Error("undefined collector", "name", m.Name, "value", m.Value, "labels", m.Labels)
+		return errors.E(op, errors.Errorf("undefined collector %s", m.Name))
+	}
+	if c == nil {
+		// can it be nil ??? I guess can't
+		return errors.E(op, errors.Errorf("undefined collector %s", m.Name))
+	}
+
+	switch c := c.(type) {
+	case prometheus.Gauge:
+		c.Sub(m.Value)
+
+	case *prometheus.GaugeVec:
+		if len(m.Labels) == 0 {
+			rpc.log.Error("required labels for collector, but none was provided", "name", m.Name, "value", m.Value)
+			return errors.E(op, errors.Errorf("required labels for collector %s", m.Name))
+		}
+
+		gauge, err := c.GetMetricWithLabelValues(m.Labels...)
+		if err != nil {
+			rpc.log.Error("failed to get metrics with label values", "collector", m.Name, "labels", m.Labels)
+			return errors.E(op, err)
+		}
+		gauge.Sub(m.Value)
+	default:
+		return errors.E(op, errors.Errorf("collector `%s` does not support method `Sub`", m.Name))
+	}
+	rpc.log.Info("Subtracting operation applied successfully", "name", m.Name, "labels", m.Labels, "value", m.Value)
+
+	*ok = true
+	return nil
+}
+
+// Observe the value (histogram and summary only).
+func (rpc *rpcServer) Observe(m *Metric, ok *bool) error {
+	const op = errors.Op("Observe metrics")
+	rpc.log.Info("Observing metric", "name", m.Name, "value", m.Value, "labels", m.Labels)
+
+	c, exist := rpc.svc.collectors.Load(m.Name)
+	if !exist {
+		rpc.log.Error("undefined collector", "name", m.Name, "value", m.Value, "labels", m.Labels)
+		return errors.E(op, errors.Errorf("undefined collector %s", m.Name))
+	}
+	if c == nil {
+		return errors.E(op, errors.Errorf("undefined collector %s", m.Name))
+	}
+
+	switch c := c.(type) {
+	case *prometheus.SummaryVec:
+		if len(m.Labels) == 0 {
+			return errors.E(op, errors.Errorf("required labels for collector `%s`", m.Name))
+		}
+
+		observer, err := c.GetMetricWithLabelValues(m.Labels...)
+		if err != nil {
+			return errors.E(op, err)
+		}
+		observer.Observe(m.Value)
+
+	case prometheus.Histogram:
+		c.Observe(m.Value)
+
+	case *prometheus.HistogramVec:
+		if len(m.Labels) == 0 {
+			return errors.E(op, errors.Errorf("required labels for collector `%s`", m.Name))
+		}
+
+		observer, err := c.GetMetricWithLabelValues(m.Labels...)
+		if err != nil {
+			rpc.log.Error("failed to get metrics with label values", "collector", m.Name, "labels", m.Labels)
+			return errors.E(op, err)
+		}
+		observer.Observe(m.Value)
+	default:
+		return errors.E(op, errors.Errorf("collector `%s` does not support method `Observe`", m.Name))
+	}
+
+	rpc.log.Info("observe operation finished successfully", "name", m.Name, "labels", m.Labels, "value", m.Value)
+
+	*ok = true
+	return nil
+}
+
+// Declare is used to register new collector in prometheus
+// THE TYPES ARE:
+// 	NamedCollector -> Collector with the name
+// 	bool -> RPC reply value
+// RETURNS:
+// 	error
+func (rpc *rpcServer) Declare(nc *NamedCollector, ok *bool) error {
+	const op = errors.Op("Declare metric")
+	rpc.log.Info("Declaring new metric", "name", nc.Name, "type", nc.Type, "namespace", nc.Namespace)
+	_, exist := rpc.svc.collectors.Load(nc.Name)
+	if exist {
+		rpc.log.Error("metric with provided name already exist", "name", nc.Name, "type", nc.Type, "namespace", nc.Namespace)
+		return errors.E(op, errors.Errorf("tried to register existing collector with the name `%s`", nc.Name))
+	}
+
+	var collector prometheus.Collector
+	switch nc.Type {
+	case Histogram:
+		opts := prometheus.HistogramOpts{
+			Name:      nc.Name,
+			Namespace: nc.Namespace,
+			Subsystem: nc.Subsystem,
+			Help:      nc.Help,
+			Buckets:   nc.Buckets,
+		}
+
+		if len(nc.Labels) != 0 {
+			collector = prometheus.NewHistogramVec(opts, nc.Labels)
+		} else {
+			collector = prometheus.NewHistogram(opts)
+		}
+	case Gauge:
+		opts := prometheus.GaugeOpts{
+			Name:      nc.Name,
+			Namespace: nc.Namespace,
+			Subsystem: nc.Subsystem,
+			Help:      nc.Help,
+		}
+
+		if len(nc.Labels) != 0 {
+			collector = prometheus.NewGaugeVec(opts, nc.Labels)
+		} else {
+			collector = prometheus.NewGauge(opts)
+		}
+	case Counter:
+		opts := prometheus.CounterOpts{
+			Name:      nc.Name,
+			Namespace: nc.Namespace,
+			Subsystem: nc.Subsystem,
+			Help:      nc.Help,
+		}
+
+		if len(nc.Labels) != 0 {
+			collector = prometheus.NewCounterVec(opts, nc.Labels)
+		} else {
+			collector = prometheus.NewCounter(opts)
+		}
+	case Summary:
+		opts := prometheus.SummaryOpts{
+			Name:      nc.Name,
+			Namespace: nc.Namespace,
+			Subsystem: nc.Subsystem,
+			Help:      nc.Help,
+		}
+
+		if len(nc.Labels) != 0 {
+			collector = prometheus.NewSummaryVec(opts, nc.Labels)
+		} else {
+			collector = prometheus.NewSummary(opts)
+		}
+
+	default:
+		return errors.E(op, errors.Errorf("unknown collector type %s", nc.Type))
+	}
+
+	// add collector to sync.Map
+	rpc.svc.collectors.Store(nc.Name, collector)
+	// that method might panic, we handle it by recover
+	err := rpc.svc.Register(collector)
+	if err != nil {
+		*ok = false
+		return errors.E(op, err)
+	}
+
+	rpc.log.Info("metric successfully added", "name", nc.Name, "type", nc.Type, "namespace", nc.Namespace)
+
+	*ok = true
+	return nil
+}
+
+// Set the metric value (only for gaude).
+func (rpc *rpcServer) Set(m *Metric, ok *bool) (err error) {
+	const op = errors.Op("Set metric")
+	rpc.log.Info("Observing metric", "name", m.Name, "value", m.Value, "labels", m.Labels)
+
+	c, exist := rpc.svc.collectors.Load(m.Name)
+	if !exist {
+		return errors.E(op, errors.Errorf("undefined collector %s", m.Name))
+	}
+	if c == nil {
+		return errors.E(op, errors.Errorf("undefined collector %s", m.Name))
+	}
+
+	switch c := c.(type) {
+	case prometheus.Gauge:
+		c.Set(m.Value)
+
+	case *prometheus.GaugeVec:
+		if len(m.Labels) == 0 {
+			rpc.log.Error("required labels for collector", "collector", m.Name)
+			return errors.E(op, errors.Errorf("required labels for collector %s", m.Name))
+		}
+
+		gauge, err := c.GetMetricWithLabelValues(m.Labels...)
+		if err != nil {
+			rpc.log.Error("failed to get metrics with label values", "collector", m.Name, "labels", m.Labels)
+			return errors.E(op, err)
+		}
+		gauge.Set(m.Value)
+
+	default:
+		return errors.E(op, errors.Errorf("collector `%s` does not support method Set", m.Name))
+	}
+
+	rpc.log.Info("set operation finished successfully", "name", m.Name, "labels", m.Labels, "value", m.Value)
+
+	*ok = true
+	return nil
+}
diff --git a/plugins/metrics/tests/.rr-test.yaml b/plugins/metrics/tests/.rr-test.yaml
new file mode 100644
index 00000000..79343e3c
--- /dev/null
+++ b/plugins/metrics/tests/.rr-test.yaml
@@ -0,0 +1,13 @@
+rpc:
+  listen: tcp://127.0.0.1:6001
+  disabled: false
+
+metrics:
+  # prometheus client address (path /metrics added automatically)
+  address: localhost:2112
+  collect:
+    app_metric:
+      type: histogram
+      help: "Custom application metric"
+      labels: [ "type" ]
+      buckets: [ 0.1, 0.2, 0.3, 1.0 ]
\ No newline at end of file
diff --git a/plugins/metrics/tests/docker-compose.yml b/plugins/metrics/tests/docker-compose.yml
new file mode 100644
index 00000000..610633b4
--- /dev/null
+++ b/plugins/metrics/tests/docker-compose.yml
@@ -0,0 +1,7 @@
+version: '3.7'
+
+services:
+  prometheus:
+    image: prom/prometheus
+    ports:
+    - 9090:9090
diff --git a/plugins/metrics/tests/metrics_test.go b/plugins/metrics/tests/metrics_test.go
new file mode 100644
index 00000000..ed5d085a
--- /dev/null
+++ b/plugins/metrics/tests/metrics_test.go
@@ -0,0 +1,754 @@
+package tests
+
+import (
+	"io/ioutil"
+	"net"
+	"net/http"
+	"net/rpc"
+	"os"
+	"os/signal"
+	"syscall"
+	"testing"
+	"time"
+
+	"github.com/spiral/endure"
+	"github.com/spiral/goridge/v2"
+	"github.com/spiral/roadrunner/v2/plugins/config"
+	"github.com/spiral/roadrunner/v2/plugins/logger"
+	"github.com/spiral/roadrunner/v2/plugins/metrics"
+	rpcPlugin "github.com/spiral/roadrunner/v2/plugins/rpc"
+	"github.com/stretchr/testify/assert"
+)
+
+const dialAddr = "127.0.0.1:6001"
+const dialNetwork = "tcp"
+const getAddr = "http://localhost:2112/metrics"
+
+// get request and return body
+func get(url string) (string, error) {
+	r, err := http.Get(url)
+	if err != nil {
+		return "", err
+	}
+
+	b, err := ioutil.ReadAll(r.Body)
+	if err != nil {
+		return "", err
+	}
+
+	err = r.Body.Close()
+	if err != nil {
+		return "", err
+	}
+	// unsafe
+	return string(b), err
+}
+
+func TestMetricsInit(t *testing.T) {
+	cont, err := endure.NewContainer(nil, endure.SetLogLevel(endure.DebugLevel))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	cfg := &config.Viper{}
+	cfg.Prefix = "rr"
+	cfg.Path = ".rr-test.yaml"
+
+	err = cont.Register(cfg)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = cont.Register(&metrics.Plugin{})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = cont.Register(&rpcPlugin.Plugin{})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = cont.Register(&logger.ZapLogger{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = cont.Register(&Plugin1{})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = cont.Init()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	ch, err := cont.Serve()
+	assert.NoError(t, err)
+
+	sig := make(chan os.Signal, 1)
+	signal.Notify(sig, os.Interrupt, syscall.SIGINT, syscall.SIGTERM)
+
+	tt := time.NewTimer(time.Second * 5)
+
+	out, err := get("http://localhost:2112/metrics")
+	assert.NoError(t, err)
+
+	assert.Contains(t, out, "go_gc_duration_seconds")
+
+	for {
+		select {
+		case e := <-ch:
+			assert.Fail(t, "error", e.Error.Error())
+			err = cont.Stop()
+			if err != nil {
+				assert.FailNow(t, "error", err.Error())
+			}
+		case <-sig:
+			err = cont.Stop()
+			if err != nil {
+				assert.FailNow(t, "error", err.Error())
+			}
+			return
+		case <-tt.C:
+			// timeout
+			err = cont.Stop()
+			if err != nil {
+				assert.FailNow(t, "error", err.Error())
+			}
+			return
+		}
+	}
+}
+
+func TestMetricsGaugeCollector(t *testing.T) {
+	cont, err := endure.NewContainer(nil, endure.SetLogLevel(endure.DebugLevel), endure.Visualize(endure.StdOut, ""))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	cfg := &config.Viper{}
+	cfg.Prefix = "rr"
+	cfg.Path = ".rr-test.yaml"
+
+	err = cont.RegisterAll(
+		cfg,
+		&metrics.Plugin{},
+		&rpcPlugin.Plugin{},
+		&logger.ZapLogger{},
+		&Plugin1{},
+	)
+	assert.NoError(t, err)
+
+	err = cont.Init()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	ch, err := cont.Serve()
+	assert.NoError(t, err)
+
+	sig := make(chan os.Signal, 1)
+	signal.Notify(sig, os.Interrupt, syscall.SIGINT, syscall.SIGTERM)
+
+	time.Sleep(time.Second)
+	tt := time.NewTimer(time.Second * 5)
+
+	out, err := get("http://localhost:2112/metrics")
+	assert.NoError(t, err)
+	assert.Contains(t, out, "my_gauge 100")
+	assert.Contains(t, out, "my_gauge2 100")
+
+	out, err = get("http://localhost:2112/metrics")
+	assert.NoError(t, err)
+	assert.Contains(t, out, "go_gc_duration_seconds")
+
+	for {
+		select {
+		case e := <-ch:
+			assert.Fail(t, "error", e.Error.Error())
+			err = cont.Stop()
+			if err != nil {
+				assert.FailNow(t, "error", err.Error())
+			}
+		case <-sig:
+			err = cont.Stop()
+			if err != nil {
+				assert.FailNow(t, "error", err.Error())
+			}
+			return
+		case <-tt.C:
+			// timeout
+			err = cont.Stop()
+			if err != nil {
+				assert.FailNow(t, "error", err.Error())
+			}
+			return
+		}
+	}
+}
+
+func TestMetricsDifferentRPCCalls(t *testing.T) {
+	cont, err := endure.NewContainer(nil, endure.SetLogLevel(endure.DebugLevel), endure.Visualize(endure.StdOut, ""))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	cfg := &config.Viper{}
+	cfg.Prefix = "rr"
+	cfg.Path = ".rr-test.yaml"
+
+	err = cont.RegisterAll(
+		cfg,
+		&metrics.Plugin{},
+		&rpcPlugin.Plugin{},
+		&logger.ZapLogger{},
+	)
+	assert.NoError(t, err)
+
+	err = cont.Init()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	ch, err := cont.Serve()
+	assert.NoError(t, err)
+
+	sig := make(chan os.Signal, 1)
+	signal.Notify(sig, os.Interrupt, syscall.SIGINT, syscall.SIGTERM)
+
+	go func() {
+		tt := time.NewTimer(time.Minute * 3)
+		for {
+			select {
+			case e := <-ch:
+				assert.Fail(t, "error", e.Error.Error())
+				err = cont.Stop()
+				if err != nil {
+					assert.FailNow(t, "error", err.Error())
+				}
+			case <-sig:
+				err = cont.Stop()
+				if err != nil {
+					assert.FailNow(t, "error", err.Error())
+				}
+				return
+			case <-tt.C:
+				// timeout
+				err = cont.Stop()
+				if err != nil {
+					assert.FailNow(t, "error", err.Error())
+				}
+				return
+			}
+		}
+	}()
+
+	t.Run("DeclareMetric", declareMetricsTest)
+	genericOut, err := get(getAddr)
+	assert.NoError(t, err)
+	assert.Contains(t, genericOut, "test_metrics_named_collector")
+
+	t.Run("AddMetric", addMetricsTest)
+	genericOut, err = get(getAddr)
+	assert.NoError(t, err)
+	assert.Contains(t, genericOut, "test_metrics_named_collector 10000")
+
+	t.Run("SetMetric", setMetric)
+	genericOut, err = get(getAddr)
+	assert.NoError(t, err)
+	assert.Contains(t, genericOut, "user_gauge_collector 100")
+
+	t.Run("VectorMetric", vectorMetric)
+	genericOut, err = get(getAddr)
+	assert.NoError(t, err)
+	assert.Contains(t, genericOut, "gauge_2_collector{section=\"first\",type=\"core\"} 100")
+
+	t.Run("MissingSection", missingSection)
+	t.Run("SetWithoutLabels", setWithoutLabels)
+	t.Run("SetOnHistogram", setOnHistogram)
+	t.Run("MetricSub", subMetric)
+	genericOut, err = get(getAddr)
+	assert.NoError(t, err)
+	assert.Contains(t, genericOut, "sub_gauge_subMetric 1")
+
+	t.Run("SubVector", subVector)
+	genericOut, err = get(getAddr)
+	assert.NoError(t, err)
+	assert.Contains(t, genericOut, "sub_gauge_subVector{section=\"first\",type=\"core\"} 1")
+
+	t.Run("RegisterHistogram", registerHistogram)
+
+	genericOut, err = get(getAddr)
+	assert.NoError(t, err)
+	assert.Contains(t, genericOut, `TYPE histogram_registerHistogram`)
+
+	// check buckets
+	assert.Contains(t, genericOut, `histogram_registerHistogram_bucket{le="0.1"} 0`)
+	assert.Contains(t, genericOut, `histogram_registerHistogram_bucket{le="0.2"} 0`)
+	assert.Contains(t, genericOut, `histogram_registerHistogram_bucket{le="0.5"} 0`)
+	assert.Contains(t, genericOut, `histogram_registerHistogram_bucket{le="+Inf"} 0`)
+	assert.Contains(t, genericOut, `histogram_registerHistogram_sum 0`)
+	assert.Contains(t, genericOut, `histogram_registerHistogram_count 0`)
+
+	t.Run("CounterMetric", counterMetric)
+	genericOut, err = get(getAddr)
+	assert.NoError(t, err)
+	assert.Contains(t, genericOut, "HELP default_default_counter_CounterMetric test_counter")
+	assert.Contains(t, genericOut, `default_default_counter_CounterMetric{section="section2",type="type2"}`)
+
+	t.Run("ObserveMetric", observeMetric)
+	genericOut, err = get(getAddr)
+	assert.NoError(t, err)
+	assert.Contains(t, genericOut, "observe_observeMetric")
+
+	t.Run("ObserveMetricNotEnoughLabels", observeMetricNotEnoughLabels)
+
+	close(sig)
+}
+
+func observeMetricNotEnoughLabels(t *testing.T) {
+	conn, err := net.Dial(dialNetwork, dialAddr)
+	assert.NoError(t, err)
+	defer func() {
+		_ = conn.Close()
+	}()
+	client := rpc.NewClientWithCodec(goridge.NewClientCodec(conn))
+	var ret bool
+
+	nc := metrics.NamedCollector{
+		Name: "observe_observeMetricNotEnoughLabels",
+		Collector: metrics.Collector{
+			Namespace: "default",
+			Subsystem: "default",
+			Help:      "test_observe",
+			Type:      metrics.Histogram,
+			Labels:    []string{"type", "section"},
+		},
+	}
+
+	err = client.Call("metrics.Declare", nc, &ret)
+	assert.NoError(t, err)
+	assert.True(t, ret)
+	ret = false
+
+	assert.Error(t, client.Call("metrics.Observe", metrics.Metric{
+		Name:   "observe_observeMetric",
+		Value:  100.0,
+		Labels: []string{"test"},
+	}, &ret))
+	assert.False(t, ret)
+}
+
+func observeMetric(t *testing.T) {
+	conn, err := net.Dial(dialNetwork, dialAddr)
+	assert.NoError(t, err)
+	defer func() {
+		_ = conn.Close()
+	}()
+	client := rpc.NewClientWithCodec(goridge.NewClientCodec(conn))
+	var ret bool
+
+	nc := metrics.NamedCollector{
+		Name: "observe_observeMetric",
+		Collector: metrics.Collector{
+			Namespace: "default",
+			Subsystem: "default",
+			Help:      "test_observe",
+			Type:      metrics.Histogram,
+			Labels:    []string{"type", "section"},
+		},
+	}
+
+	err = client.Call("metrics.Declare", nc, &ret)
+	assert.NoError(t, err)
+	assert.True(t, ret)
+	ret = false
+
+	assert.NoError(t, client.Call("metrics.Observe", metrics.Metric{
+		Name:   "observe_observeMetric",
+		Value:  100.0,
+		Labels: []string{"test", "test2"},
+	}, &ret))
+	assert.True(t, ret)
+}
+
+func counterMetric(t *testing.T) {
+	conn, err := net.Dial(dialNetwork, dialAddr)
+	assert.NoError(t, err)
+	defer func() {
+		_ = conn.Close()
+	}()
+	client := rpc.NewClientWithCodec(goridge.NewClientCodec(conn))
+	var ret bool
+
+	nc := metrics.NamedCollector{
+		Name: "counter_CounterMetric",
+		Collector: metrics.Collector{
+			Namespace: "default",
+			Subsystem: "default",
+			Help:      "test_counter",
+			Type:      metrics.Counter,
+			Labels:    []string{"type", "section"},
+		},
+	}
+
+	err = client.Call("metrics.Declare", nc, &ret)
+	assert.NoError(t, err)
+	assert.True(t, ret)
+
+	ret = false
+
+	assert.NoError(t, client.Call("metrics.Add", metrics.Metric{
+		Name:   "counter_CounterMetric",
+		Value:  100.0,
+		Labels: []string{"type2", "section2"},
+	}, &ret))
+	assert.True(t, ret)
+}
+
+func registerHistogram(t *testing.T) {
+	conn, err := net.Dial(dialNetwork, dialAddr)
+	assert.NoError(t, err)
+	defer func() {
+		_ = conn.Close()
+	}()
+	client := rpc.NewClientWithCodec(goridge.NewClientCodec(conn))
+	var ret bool
+
+	nc := metrics.NamedCollector{
+		Name: "histogram_registerHistogram",
+		Collector: metrics.Collector{
+			Help:    "test_histogram",
+			Type:    metrics.Histogram,
+			Buckets: []float64{0.1, 0.2, 0.5},
+		},
+	}
+
+	err = client.Call("metrics.Declare", nc, &ret)
+	assert.NoError(t, err)
+	assert.True(t, ret)
+
+	ret = false
+
+	m := metrics.Metric{
+		Name:   "histogram_registerHistogram",
+		Value:  10000,
+		Labels: nil,
+	}
+
+	err = client.Call("metrics.Add", m, &ret)
+	assert.Error(t, err)
+	assert.False(t, ret)
+}
+
+func subVector(t *testing.T) {
+	conn, err := net.Dial(dialNetwork, dialAddr)
+	assert.NoError(t, err)
+	defer func() {
+		_ = conn.Close()
+	}()
+
+	client := rpc.NewClientWithCodec(goridge.NewClientCodec(conn))
+	var ret bool
+
+	nc := metrics.NamedCollector{
+		Name: "sub_gauge_subVector",
+		Collector: metrics.Collector{
+			Namespace: "default",
+			Subsystem: "default",
+			Type:      metrics.Gauge,
+			Labels:    []string{"type", "section"},
+		},
+	}
+
+	err = client.Call("metrics.Declare", nc, &ret)
+	assert.NoError(t, err)
+	assert.True(t, ret)
+	ret = false
+
+	m := metrics.Metric{
+		Name:   "sub_gauge_subVector",
+		Value:  100000,
+		Labels: []string{"core", "first"},
+	}
+
+	err = client.Call("metrics.Add", m, &ret)
+	assert.NoError(t, err)
+	assert.True(t, ret)
+	ret = false
+
+	m = metrics.Metric{
+		Name:   "sub_gauge_subVector",
+		Value:  99999,
+		Labels: []string{"core", "first"},
+	}
+
+	err = client.Call("metrics.Sub", m, &ret)
+	assert.NoError(t, err)
+	assert.True(t, ret)
+}
+
+func subMetric(t *testing.T) {
+	conn, err := net.Dial(dialNetwork, dialAddr)
+	assert.NoError(t, err)
+	defer func() {
+		_ = conn.Close()
+	}()
+	client := rpc.NewClientWithCodec(goridge.NewClientCodec(conn))
+	var ret bool
+
+	nc := metrics.NamedCollector{
+		Name: "sub_gauge_subMetric",
+		Collector: metrics.Collector{
+			Namespace: "default",
+			Subsystem: "default",
+			Type:      metrics.Gauge,
+		},
+	}
+
+	err = client.Call("metrics.Declare", nc, &ret)
+	assert.NoError(t, err)
+	assert.True(t, ret)
+	ret = false
+
+	m := metrics.Metric{
+		Name:  "sub_gauge_subMetric",
+		Value: 100000,
+	}
+
+	err = client.Call("metrics.Add", m, &ret)
+	assert.NoError(t, err)
+	assert.True(t, ret)
+	ret = false
+
+	m = metrics.Metric{
+		Name:  "sub_gauge_subMetric",
+		Value: 99999,
+	}
+
+	err = client.Call("metrics.Sub", m, &ret)
+	assert.NoError(t, err)
+	assert.True(t, ret)
+}
+
+func setOnHistogram(t *testing.T) {
+	conn, err := net.Dial(dialNetwork, dialAddr)
+	assert.NoError(t, err)
+	defer func() {
+		_ = conn.Close()
+	}()
+	client := rpc.NewClientWithCodec(goridge.NewClientCodec(conn))
+	var ret bool
+
+	nc := metrics.NamedCollector{
+		Name: "histogram_setOnHistogram",
+		Collector: metrics.Collector{
+			Namespace: "default",
+			Subsystem: "default",
+			Type:      metrics.Histogram,
+			Labels:    []string{"type", "section"},
+		},
+	}
+
+	err = client.Call("metrics.Declare", nc, &ret)
+	assert.NoError(t, err)
+	assert.True(t, ret)
+
+	ret = false
+
+	m := metrics.Metric{
+		Name:  "gauge_setOnHistogram",
+		Value: 100.0,
+	}
+
+	err = client.Call("metrics.Set", m, &ret) // expected 2 label values but got 1 in []string{"missing"}
+	assert.Error(t, err)
+	assert.False(t, ret)
+}
+
+func setWithoutLabels(t *testing.T) {
+	conn, err := net.Dial(dialNetwork, dialAddr)
+	assert.NoError(t, err)
+	defer func() {
+		_ = conn.Close()
+	}()
+	client := rpc.NewClientWithCodec(goridge.NewClientCodec(conn))
+	var ret bool
+
+	nc := metrics.NamedCollector{
+		Name: "gauge_setWithoutLabels",
+		Collector: metrics.Collector{
+			Namespace: "default",
+			Subsystem: "default",
+			Type:      metrics.Gauge,
+			Labels:    []string{"type", "section"},
+		},
+	}
+
+	err = client.Call("metrics.Declare", nc, &ret)
+	assert.NoError(t, err)
+	assert.True(t, ret)
+
+	ret = false
+
+	m := metrics.Metric{
+		Name:  "gauge_setWithoutLabels",
+		Value: 100.0,
+	}
+
+	err = client.Call("metrics.Set", m, &ret) // expected 2 label values but got 1 in []string{"missing"}
+	assert.Error(t, err)
+	assert.False(t, ret)
+}
+
+func missingSection(t *testing.T) {
+	conn, err := net.Dial(dialNetwork, dialAddr)
+	assert.NoError(t, err)
+	defer func() {
+		_ = conn.Close()
+	}()
+	client := rpc.NewClientWithCodec(goridge.NewClientCodec(conn))
+	var ret bool
+
+	nc := metrics.NamedCollector{
+		Name: "gauge_missing_section_collector",
+		Collector: metrics.Collector{
+			Namespace: "default",
+			Subsystem: "default",
+			Type:      metrics.Gauge,
+			Labels:    []string{"type", "section"},
+		},
+	}
+
+	err = client.Call("metrics.Declare", nc, &ret)
+	assert.NoError(t, err)
+	assert.True(t, ret)
+
+	ret = false
+
+	m := metrics.Metric{
+		Name:   "gauge_missing_section_collector",
+		Value:  100.0,
+		Labels: []string{"missing"},
+	}
+
+	err = client.Call("metrics.Set", m, &ret) // expected 2 label values but got 1 in []string{"missing"}
+	assert.Error(t, err)
+	assert.False(t, ret)
+}
+
+func vectorMetric(t *testing.T) {
+	conn, err := net.Dial(dialNetwork, dialAddr)
+	assert.NoError(t, err)
+	defer func() {
+		_ = conn.Close()
+	}()
+	client := rpc.NewClientWithCodec(goridge.NewClientCodec(conn))
+	var ret bool
+
+	nc := metrics.NamedCollector{
+		Name: "gauge_2_collector",
+		Collector: metrics.Collector{
+			Namespace: "default",
+			Subsystem: "default",
+			Type:      metrics.Gauge,
+			Labels:    []string{"type", "section"},
+		},
+	}
+
+	err = client.Call("metrics.Declare", nc, &ret)
+	assert.NoError(t, err)
+	assert.True(t, ret)
+
+	ret = false
+
+	m := metrics.Metric{
+		Name:   "gauge_2_collector",
+		Value:  100.0,
+		Labels: []string{"core", "first"},
+	}
+
+	err = client.Call("metrics.Set", m, &ret)
+	assert.NoError(t, err)
+	assert.True(t, ret)
+}
+
+func setMetric(t *testing.T) {
+	conn, err := net.Dial(dialNetwork, dialAddr)
+	assert.NoError(t, err)
+	defer func() {
+		_ = conn.Close()
+	}()
+	client := rpc.NewClientWithCodec(goridge.NewClientCodec(conn))
+	var ret bool
+
+	nc := metrics.NamedCollector{
+		Name: "user_gauge_collector",
+		Collector: metrics.Collector{
+			Namespace: "default",
+			Subsystem: "default",
+			Type:      metrics.Gauge,
+		},
+	}
+
+	err = client.Call("metrics.Declare", nc, &ret)
+	assert.NoError(t, err)
+	assert.True(t, ret)
+	ret = false
+
+	m := metrics.Metric{
+		Name:  "user_gauge_collector",
+		Value: 100.0,
+	}
+
+	err = client.Call("metrics.Set", m, &ret)
+	assert.NoError(t, err)
+	assert.True(t, ret)
+}
+
+func addMetricsTest(t *testing.T) {
+	conn, err := net.Dial(dialNetwork, dialAddr)
+	assert.NoError(t, err)
+	defer func() {
+		_ = conn.Close()
+	}()
+	client := rpc.NewClientWithCodec(goridge.NewClientCodec(conn))
+	var ret bool
+
+	m := metrics.Metric{
+		Name:   "test_metrics_named_collector",
+		Value:  10000,
+		Labels: nil,
+	}
+
+	err = client.Call("metrics.Add", m, &ret)
+	assert.NoError(t, err)
+	assert.True(t, ret)
+}
+
+func declareMetricsTest(t *testing.T) {
+	conn, err := net.Dial(dialNetwork, dialAddr)
+	assert.NoError(t, err)
+	defer func() {
+		_ = conn.Close()
+	}()
+	client := rpc.NewClientWithCodec(goridge.NewClientCodec(conn))
+	var ret bool
+
+	nc := metrics.NamedCollector{
+		Name: "test_metrics_named_collector",
+		Collector: metrics.Collector{
+			Namespace: "default",
+			Subsystem: "default",
+			Type:      metrics.Counter,
+			Help:      "NO HELP!",
+			Labels:    nil,
+			Buckets:   nil,
+		},
+	}
+
+	err = client.Call("metrics.Declare", nc, &ret)
+	assert.NoError(t, err)
+	assert.True(t, ret)
+}
diff --git a/plugins/metrics/tests/plugin1.go b/plugins/metrics/tests/plugin1.go
new file mode 100644
index 00000000..b48c415d
--- /dev/null
+++ b/plugins/metrics/tests/plugin1.go
@@ -0,0 +1,46 @@
+package tests
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/spiral/roadrunner/v2/plugins/config"
+)
+
+// Gauge //////////////
+type Plugin1 struct {
+	config config.Configurer
+}
+
+func (p1 *Plugin1) Init(cfg config.Configurer) error {
+	p1.config = cfg
+	return nil
+}
+
+func (p1 *Plugin1) Serve() chan error {
+	errCh := make(chan error, 1)
+	return errCh
+}
+
+func (p1 *Plugin1) Stop() error {
+	return nil
+}
+
+func (p1 *Plugin1) Name() string {
+	return "metrics_test.plugin1"
+}
+
+func (p1 *Plugin1) MetricsCollector() []prometheus.Collector {
+	collector := prometheus.NewGauge(prometheus.GaugeOpts{
+		Name: "my_gauge",
+		Help: "My gauge value",
+	})
+
+	collector.Set(100)
+
+	collector2 := prometheus.NewGauge(prometheus.GaugeOpts{
+		Name: "my_gauge2",
+		Help: "My gauge2 value",
+	})
+
+	collector2.Set(100)
+	return []prometheus.Collector{collector, collector2}
+}
diff --git a/plugins/rpc/plugin.go b/plugins/rpc/plugin.go
index 6401c0e2..82b30563 100755
--- a/plugins/rpc/plugin.go
+++ b/plugins/rpc/plugin.go
@@ -8,27 +8,25 @@ import (
 	"github.com/spiral/endure"
 	"github.com/spiral/errors"
 	"github.com/spiral/goridge/v2"
-	"github.com/spiral/roadrunner/v2/log"
+	"github.com/spiral/roadrunner/v2/interfaces/log"
+	rpc_ "github.com/spiral/roadrunner/v2/interfaces/rpc"
 	"github.com/spiral/roadrunner/v2/plugins/config"
 )
 
-// Pluggable declares the ability to create set of public RPC methods.
-type Pluggable interface {
-	endure.Named
-
-	// Provides RPC methods for the given service.
-	RPCService() (interface{}, error)
-}
-
 // ServiceName contains default service name.
 const ServiceName = "RPC"
 
+type pluggable struct {
+	service rpc_.RPCer
+	name    string
+}
+
 // Plugin is RPC service.
 type Plugin struct {
 	cfg      Config
 	log      log.Logger
 	rpc      *rpc.Server
-	services []Pluggable
+	services []pluggable
 	listener net.Listener
 	closed   *uint32
 }
@@ -69,19 +67,13 @@ func (s *Plugin) Serve() chan error {
 
 	// Attach all services
 	for i := 0; i < len(s.services); i++ {
-		svc, err := s.services[i].RPCService()
+		err := s.Register(s.services[i].name, s.services[i].service.RPC())
 		if err != nil {
 			errCh <- errors.E(op, err)
 			return errCh
 		}
 
-		err = s.Register(s.services[i].Name(), svc)
-		if err != nil {
-			errCh <- errors.E(op, err)
-			return errCh
-		}
-
-		services = append(services, s.services[i].Name())
+		services = append(services, s.services[i].name)
 	}
 
 	var err error
@@ -139,9 +131,11 @@ func (s *Plugin) Collects() []interface{} {
 }
 
 // RegisterPlugin registers RPC service plugin.
-func (s *Plugin) RegisterPlugin(p Pluggable) error {
-	s.services = append(s.services, p)
-	return nil
+func (s *Plugin) RegisterPlugin(name endure.Named, p rpc_.RPCer) {
+	s.services = append(s.services, pluggable{
+		service: p,
+		name:    name.Name(),
+	})
 }
 
 // Register publishes in the server the set of methods of the
diff --git a/plugins/rpc/tests/plugin1.go b/plugins/rpc/tests/plugin1.go
index 788e6a2c..a8d5c216 100644
--- a/plugins/rpc/tests/plugin1.go
+++ b/plugins/rpc/tests/plugin1.go
@@ -28,8 +28,8 @@ func (p1 *Plugin1) Name() string {
 	return "rpc_test.plugin1"
 }
 
-func (p1 *Plugin1) RPCService() (interface{}, error) {
-	return &PluginRpc{srv: p1}, nil
+func (p1 *Plugin1) RPC() interface{} {
+	return &PluginRpc{srv: p1}
 }
 
 type PluginRpc struct {
diff --git a/plugins/app/config.go b/plugins/server/config.go
index eaa54e2d..147ae0f7 100644
--- a/plugins/app/config.go
+++ b/plugins/server/config.go
@@ -1,6 +1,10 @@
-package app
+package server
 
-import "time"
+import (
+	"time"
+
+	"github.com/spiral/roadrunner/v2/interfaces/server"
+)
 
 // Config config combines factory, pool and cmd configurations.
 type Config struct {
@@ -14,7 +18,7 @@ type Config struct {
 	Group string
 
 	// Env represents application environment.
-	Env Env
+	Env server.Env
 
 	// Listen defines connection method and factory to be used to connect to workers:
 	// "pipes", "tcp://:6001", "unix://rr.sock"
diff --git a/plugins/app/plugin.go b/plugins/server/plugin.go
index d76961ca..e096708a 100644
--- a/plugins/app/plugin.go
+++ b/plugins/server/plugin.go
@@ -1,4 +1,4 @@
-package app
+package server
 
 import (
 	"context"
@@ -9,21 +9,13 @@ import (
 
 	"github.com/spiral/errors"
 	"github.com/spiral/roadrunner/v2"
-	"github.com/spiral/roadrunner/v2/log"
+	"github.com/spiral/roadrunner/v2/interfaces/log"
+	"github.com/spiral/roadrunner/v2/interfaces/server"
 	"github.com/spiral/roadrunner/v2/plugins/config"
 	"github.com/spiral/roadrunner/v2/util"
 )
 
-const ServiceName = "app"
-
-type Env map[string]string
-
-// WorkerFactory creates workers for the application.
-type WorkerFactory interface {
-	CmdFactory(env Env) (func() *exec.Cmd, error)
-	NewWorker(ctx context.Context, env Env) (roadrunner.WorkerBase, error)
-	NewWorkerPool(ctx context.Context, opt roadrunner.Config, env Env) (roadrunner.Pool, error)
-}
+const ServiceName = "server"
 
 // Plugin manages worker
 type Plugin struct {
@@ -71,7 +63,7 @@ func (app *Plugin) Stop() error {
 }
 
 // CmdFactory provides worker command factory assocated with given context.
-func (app *Plugin) CmdFactory(env Env) (func() *exec.Cmd, error) {
+func (app *Plugin) CmdFactory(env server.Env) (func() *exec.Cmd, error) {
 	var cmdArgs []string
 
 	// create command according to the config
@@ -97,7 +89,7 @@ func (app *Plugin) CmdFactory(env Env) (func() *exec.Cmd, error) {
 }
 
 // NewWorker issues new standalone worker.
-func (app *Plugin) NewWorker(ctx context.Context, env Env) (roadrunner.WorkerBase, error) {
+func (app *Plugin) NewWorker(ctx context.Context, env server.Env) (roadrunner.WorkerBase, error) {
 	const op = errors.Op("new worker")
 	spawnCmd, err := app.CmdFactory(env)
 	if err != nil {
@@ -115,7 +107,7 @@ func (app *Plugin) NewWorker(ctx context.Context, env Env) (roadrunner.WorkerBas
 }
 
 // NewWorkerPool issues new worker pool.
-func (app *Plugin) NewWorkerPool(ctx context.Context, opt roadrunner.Config, env Env) (roadrunner.Pool, error) {
+func (app *Plugin) NewWorkerPool(ctx context.Context, opt roadrunner.PoolConfig, env server.Env) (roadrunner.Pool, error) {
 	spawnCmd, err := app.CmdFactory(env)
 	if err != nil {
 		return nil, err
@@ -159,7 +151,7 @@ func (app *Plugin) initFactory() (roadrunner.Factory, error) {
 	}
 }
 
-func (app *Plugin) setEnv(e Env) []string {
+func (app *Plugin) setEnv(e server.Env) []string {
 	env := append(os.Environ(), fmt.Sprintf("RR_RELAY=%s", app.cfg.Relay))
 	for k, v := range e {
 		env = append(env, fmt.Sprintf("%s=%s", strings.ToUpper(k), v))
diff --git a/plugins/app/tests/configs/.rr-no-app-section.yaml b/plugins/server/tests/configs/.rr-no-app-section.yaml
index d129ae8a..b6e3ea93 100644
--- a/plugins/app/tests/configs/.rr-no-app-section.yaml
+++ b/plugins/server/tests/configs/.rr-no-app-section.yaml
@@ -1,4 +1,4 @@
-upp:
+server:
   command: "php ../../../tests/client.php echo pipes"
   user: ""
   group: ""
diff --git a/plugins/app/tests/configs/.rr-sockets.yaml b/plugins/server/tests/configs/.rr-sockets.yaml
index 9bd62693..ab1239aa 100644
--- a/plugins/app/tests/configs/.rr-sockets.yaml
+++ b/plugins/server/tests/configs/.rr-sockets.yaml
@@ -1,4 +1,4 @@
-app:
+server:
   command: "php socket.php"
   user: ""
   group: ""
diff --git a/plugins/app/tests/configs/.rr-tcp.yaml b/plugins/server/tests/configs/.rr-tcp.yaml
index c5a26d37..f53bffcc 100644
--- a/plugins/app/tests/configs/.rr-tcp.yaml
+++ b/plugins/server/tests/configs/.rr-tcp.yaml
@@ -1,4 +1,4 @@
-app:
+server:
   command: "php tcp.php"
   user: ""
   group: ""
diff --git a/plugins/app/tests/configs/.rr-wrong-command.yaml b/plugins/server/tests/configs/.rr-wrong-command.yaml
index 4bd019d3..d2c087a6 100644
--- a/plugins/app/tests/configs/.rr-wrong-command.yaml
+++ b/plugins/server/tests/configs/.rr-wrong-command.yaml
@@ -1,4 +1,4 @@
-app:
+server:
   command: "php some_absent_file.php"
   user: ""
   group: ""
diff --git a/plugins/app/tests/configs/.rr-wrong-relay.yaml b/plugins/server/tests/configs/.rr-wrong-relay.yaml
index d8ffe8f8..1dd73d73 100644
--- a/plugins/app/tests/configs/.rr-wrong-relay.yaml
+++ b/plugins/server/tests/configs/.rr-wrong-relay.yaml
@@ -1,4 +1,4 @@
-app:
+server:
   command: "php ../../../tests/client.php echo pipes"
   user: ""
   group: ""
diff --git a/plugins/app/tests/configs/.rr.yaml b/plugins/server/tests/configs/.rr.yaml
index 221aff92..b6e3ea93 100644
--- a/plugins/app/tests/configs/.rr.yaml
+++ b/plugins/server/tests/configs/.rr.yaml
@@ -1,4 +1,4 @@
-app:
+server:
   command: "php ../../../tests/client.php echo pipes"
   user: ""
   group: ""
diff --git a/plugins/app/tests/plugin_pipes.go b/plugins/server/tests/plugin_pipes.go
index fc999718..840021eb 100644
--- a/plugins/app/tests/plugin_pipes.go
+++ b/plugins/server/tests/plugin_pipes.go
@@ -6,14 +6,15 @@ import (
 
 	"github.com/spiral/errors"
 	"github.com/spiral/roadrunner/v2"
-	"github.com/spiral/roadrunner/v2/plugins/app"
+	"github.com/spiral/roadrunner/v2/interfaces/server"
 	"github.com/spiral/roadrunner/v2/plugins/config"
+	plugin "github.com/spiral/roadrunner/v2/plugins/server"
 )
 
 const ConfigSection = "app"
 const Response = "test"
 
-var testPoolConfig = roadrunner.Config{
+var testPoolConfig = roadrunner.PoolConfig{
 	NumWorkers:      10,
 	MaxJobs:         100,
 	AllocateTimeout: time.Second * 10,
@@ -29,11 +30,11 @@ var testPoolConfig = roadrunner.Config{
 
 type Foo struct {
 	configProvider config.Configurer
-	wf             app.WorkerFactory
+	wf             server.WorkerFactory
 	pool           roadrunner.Pool
 }
 
-func (f *Foo) Init(p config.Configurer, workerFactory app.WorkerFactory) error {
+func (f *Foo) Init(p config.Configurer, workerFactory server.WorkerFactory) error {
 	f.configProvider = p
 	f.wf = workerFactory
 	return nil
@@ -50,7 +51,7 @@ func (f *Foo) Serve() chan error {
 
 	errCh := make(chan error, 1)
 
-	conf := &app.Config{}
+	conf := &plugin.Config{}
 	var err error
 	err = f.configProvider.UnmarshalKey(ConfigSection, conf)
 	if err != nil {
diff --git a/plugins/app/tests/plugin_sockets.go b/plugins/server/tests/plugin_sockets.go
index 585264f6..b12f4ead 100644
--- a/plugins/app/tests/plugin_sockets.go
+++ b/plugins/server/tests/plugin_sockets.go
@@ -5,17 +5,18 @@ import (
 
 	"github.com/spiral/errors"
 	"github.com/spiral/roadrunner/v2"
-	"github.com/spiral/roadrunner/v2/plugins/app"
+	"github.com/spiral/roadrunner/v2/interfaces/server"
 	"github.com/spiral/roadrunner/v2/plugins/config"
+	plugin "github.com/spiral/roadrunner/v2/plugins/server"
 )
 
 type Foo2 struct {
 	configProvider config.Configurer
-	wf             app.WorkerFactory
+	wf             server.WorkerFactory
 	pool           roadrunner.Pool
 }
 
-func (f *Foo2) Init(p config.Configurer, workerFactory app.WorkerFactory) error {
+func (f *Foo2) Init(p config.Configurer, workerFactory server.WorkerFactory) error {
 	f.configProvider = p
 	f.wf = workerFactory
 	return nil
@@ -25,7 +26,7 @@ func (f *Foo2) Serve() chan error {
 	const op = errors.Op("serve")
 	var err error
 	errCh := make(chan error, 1)
-	conf := &app.Config{}
+	conf := &plugin.Config{}
 
 	// test payload for echo
 	r := roadrunner.Payload{
diff --git a/plugins/app/tests/plugin_tcp.go b/plugins/server/tests/plugin_tcp.go
index 6abc533d..39044577 100644
--- a/plugins/app/tests/plugin_tcp.go
+++ b/plugins/server/tests/plugin_tcp.go
@@ -5,17 +5,18 @@ import (
 
 	"github.com/spiral/errors"
 	"github.com/spiral/roadrunner/v2"
-	"github.com/spiral/roadrunner/v2/plugins/app"
+	"github.com/spiral/roadrunner/v2/interfaces/server"
 	"github.com/spiral/roadrunner/v2/plugins/config"
+	plugin "github.com/spiral/roadrunner/v2/plugins/server"
 )
 
 type Foo3 struct {
 	configProvider config.Configurer
-	wf             app.WorkerFactory
+	wf             server.WorkerFactory
 	pool           roadrunner.Pool
 }
 
-func (f *Foo3) Init(p config.Configurer, workerFactory app.WorkerFactory) error {
+func (f *Foo3) Init(p config.Configurer, workerFactory server.WorkerFactory) error {
 	f.configProvider = p
 	f.wf = workerFactory
 	return nil
@@ -25,7 +26,7 @@ func (f *Foo3) Serve() chan error {
 	const op = errors.Op("serve")
 	var err error
 	errCh := make(chan error, 1)
-	conf := &app.Config{}
+	conf := &plugin.Config{}
 
 	// test payload for echo
 	r := roadrunner.Payload{
diff --git a/plugins/app/tests/app_test.go b/plugins/server/tests/server_test.go
index 3c416b59..f917df5d 100644
--- a/plugins/app/tests/app_test.go
+++ b/plugins/server/tests/server_test.go
@@ -7,9 +7,9 @@ import (
 	"time"
 
 	"github.com/spiral/endure"
-	"github.com/spiral/roadrunner/v2/plugins/app"
 	"github.com/spiral/roadrunner/v2/plugins/config"
 	"github.com/spiral/roadrunner/v2/plugins/logger"
+	"github.com/spiral/roadrunner/v2/plugins/server"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -27,7 +27,7 @@ func TestAppPipes(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	err = container.Register(&app.Plugin{})
+	err = container.Register(&server.Plugin{})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -93,7 +93,7 @@ func TestAppSockets(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	err = container.Register(&app.Plugin{})
+	err = container.Register(&server.Plugin{})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -159,7 +159,7 @@ func TestAppTCP(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	err = container.Register(&app.Plugin{})
+	err = container.Register(&server.Plugin{})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -225,7 +225,7 @@ func TestAppWrongConfig(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	err = container.Register(&app.Plugin{})
+	err = container.Register(&server.Plugin{})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -257,7 +257,7 @@ func TestAppWrongRelay(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	err = container.Register(&app.Plugin{})
+	err = container.Register(&server.Plugin{})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -295,7 +295,7 @@ func TestAppWrongCommand(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	err = container.Register(&app.Plugin{})
+	err = container.Register(&server.Plugin{})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -333,7 +333,7 @@ func TestAppNoAppSectionInConfig(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	err = container.Register(&app.Plugin{})
+	err = container.Register(&server.Plugin{})
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/plugins/app/tests/socket.php b/plugins/server/tests/socket.php
index 143c3ce4..143c3ce4 100644
--- a/plugins/app/tests/socket.php
+++ b/plugins/server/tests/socket.php
diff --git a/plugins/app/tests/tcp.php b/plugins/server/tests/tcp.php
index 2d6fb00a..2d6fb00a 100644
--- a/plugins/app/tests/tcp.php
+++ b/plugins/server/tests/tcp.php