[#1868] Reload config for pprof and metrics on SIGHUP

Signed-off-by: Anton Nikiforov <an.nikiforov@yadro.com>

CHANGELOG.md

@@ -10,6 +10,7 @@ Changelog for FrostFS Node
 - New `frostfs_node_object_payload_size` metric for tracking size of reqular objects on a single shard (#1794)
 - Add command `frostfs-adm morph netmap-candidates` (#1889)
 - `object.delete.tombstone_lifetime` config parameter to set tombstone lifetime in the DELETE service (#2246)
+- Reload config for pprof and metrics on SIGHUP in `neofs-node` (#1868)
 
 ### Changed
 - Change `frostfs_node_engine_container_size` to counting sizes of logical objects

cmd/frostfs-ir/main.go

@@ -126,7 +126,7 @@ func initHTTPServers(cfg *viper.Viper, log *logger.Logger) []*httputil.Server {
 
 		addr := cfg.GetString(item.cfgPrefix + ".address")
 
-		var prm httputil.Prm
+		var prm httputil.HTTPSrvPrm
 
 		prm.Address = addr
 		prm.Handler = item.handler()

cmd/frostfs-node/closer.go

@@ -0,0 +1,25 @@
+package main
+
+type closer struct {
+	name string
+	fn   func()
+}
+
+func getCloser(c *cfg, name string) *closer {
+	for _, clsr := range c.closers {
+		if clsr.name == name {
+			return &clsr
+		}
+	}
+	return nil
+}
+
+func delCloser(c *cfg, name string) {
+	for i, clsr := range c.closers {
+		if clsr.name == name {
+			c.closers[i] = c.closers[len(c.closers)-1]
+			c.closers = c.closers[:len(c.closers)-1]
+			return
+		}
+	}
+}

cmd/frostfs-node/config.go

@@ -24,7 +24,6 @@ import (
 	blobovniczaconfig "github.com/TrueCloudLab/frostfs-node/cmd/frostfs-node/config/engine/shard/blobstor/blobovnicza"
 	fstreeconfig "github.com/TrueCloudLab/frostfs-node/cmd/frostfs-node/config/engine/shard/blobstor/fstree"
 	loggerconfig "github.com/TrueCloudLab/frostfs-node/cmd/frostfs-node/config/logger"
-	metricsconfig "github.com/TrueCloudLab/frostfs-node/cmd/frostfs-node/config/metrics"
 	nodeconfig "github.com/TrueCloudLab/frostfs-node/cmd/frostfs-node/config/node"
 	objectconfig "github.com/TrueCloudLab/frostfs-node/cmd/frostfs-node/config/object"
 	replicatorconfig "github.com/TrueCloudLab/frostfs-node/cmd/frostfs-node/config/replicator"
@@ -48,6 +47,7 @@ import (
 	"github.com/TrueCloudLab/frostfs-node/pkg/network"
 	"github.com/TrueCloudLab/frostfs-node/pkg/network/cache"
 	"github.com/TrueCloudLab/frostfs-node/pkg/services/control"
+	objectService "github.com/TrueCloudLab/frostfs-node/pkg/services/object"
 	getsvc "github.com/TrueCloudLab/frostfs-node/pkg/services/object/get"
 	"github.com/TrueCloudLab/frostfs-node/pkg/services/object_manager/tombstone"
 	tsourse "github.com/TrueCloudLab/frostfs-node/pkg/services/object_manager/tombstone/source"
@@ -308,7 +308,7 @@ type internals struct {
 
 	wg      *sync.WaitGroup
 	workers []worker
-	closers []func()
+	closers []closer
 
 	apiVersion   version.Version
 	healthStatus *atomic.Int32
@@ -364,12 +364,16 @@ type shared struct {
 	treeService *tree.Service
 
 	metricsCollector *metrics.NodeMetrics
+
+	metricsSvc *objectService.MetricCollector
 }
 
 // dynamicConfiguration stores parameters of the
 // components that supports runtime reconfigurations.
 type dynamicConfiguration struct {
-	logger *logger.Prm
+	logger  *logger.Prm
+	pprof   *httpComponent
+	metrics *httpComponent
 }
 
 type cfg struct {
@@ -612,10 +616,8 @@ func initCfg(appCfg *config.Config) *cfg {
 
 	user.IDFromKey(&c.ownerIDFromKey, key.PrivateKey.PublicKey)
 
-	if metricsconfig.Enabled(c.appCfg) {
-		c.metricsCollector = metrics.NewNodeMetrics()
-		netState.metrics = c.metricsCollector
-	}
+	c.metricsCollector = metrics.NewNodeMetrics()
+	netState.metrics = c.metricsCollector
 
 	c.onShutdown(c.clientCache.CloseAll)    // clean up connections
 	c.onShutdown(c.bgClientCache.CloseAll)  // clean up connections
@@ -915,11 +917,9 @@ func (c *cfg) ObjectServiceLoad() float64 {
 	return float64(c.cfgObject.pool.putRemote.Running()) / float64(c.cfgObject.pool.putRemoteCapacity)
 }
 
-type dCfg struct {
-	name string
-	cfg  interface {
-		Reload() error
-	}
+type dCmp struct {
+	name       string
+	reloadFunc func() error
 }
 
 func (c *cfg) signalWatcher() {
@@ -964,7 +964,7 @@ func (c *cfg) reloadConfig() {
 
 	// all the components are expected to support
 	// Logger's dynamic reconfiguration approach
-	var components []dCfg
+	var components []dCmp
 
 	// Logger
 
@@ -974,7 +974,18 @@ func (c *cfg) reloadConfig() {
 		return
 	}
 
-	components = append(components, dCfg{name: "logger", cfg: logPrm})
+	components = append(components, dCmp{"logger", logPrm.Reload})
+	if cmp, updated := metricsComponent(c); updated {
+		if cmp.enabled {
+			cmp.preReload = enableMetricsSvc
+		} else {
+			cmp.preReload = disableMetricsSvc
+		}
+		components = append(components, dCmp{cmp.name, cmp.reload})
+	}
+	if cmp, updated := pprofComponent(c); updated {
+		components = append(components, dCmp{cmp.name, cmp.reload})
+	}
 
 	// Storage Engine
 
@@ -990,7 +1001,7 @@ func (c *cfg) reloadConfig() {
 	}
 
 	for _, component := range components {
-		err = component.cfg.Reload()
+		err = component.reloadFunc()
 		if err != nil {
 			c.log.Error("updated configuration applying",
 				zap.String("component", component.name),
@@ -1006,7 +1017,7 @@ func (c *cfg) shutdown() {
 
 	c.ctxCancel()
 	for i := range c.closers {
-		c.closers[len(c.closers)-1-i]()
+		c.closers[len(c.closers)-1-i].fn()
 	}
 	close(c.internalErr)
 }

cmd/frostfs-node/httpcomponent.go

@@ -0,0 +1,70 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"time"
+
+	httputil "github.com/TrueCloudLab/frostfs-node/pkg/util/http"
+)
+
+type httpComponent struct {
+	address     string
+	name        string
+	handler     http.Handler
+	shutdownDur time.Duration
+	enabled     bool
+	cfg         *cfg
+	preReload   func(c *cfg)
+}
+
+func (cmp *httpComponent) init(c *cfg) {
+	if !cmp.enabled {
+		c.log.Info(fmt.Sprintf("%s is disabled", cmp.name))
+		return
+	}
+	// Init server with parameters
+	srv := httputil.New(
+		*httputil.NewHTTPSrvPrm(
+			cmp.address,
+			cmp.handler,
+		),
+		httputil.WithShutdownTimeout(
+			cmp.shutdownDur,
+		),
+	)
+	c.closers = append(c.closers, closer{
+		cmp.name,
+		func() { stopAndLog(c, cmp.name, srv.Shutdown) },
+	})
+	c.workers = append(c.workers, worker{
+		cmp.name,
+		func(ctx context.Context) {
+			runAndLog(c, cmp.name, false, func(c *cfg) {
+				fatalOnErr(srv.Serve())
+			})
+		},
+	})
+}
+
+func (cmp *httpComponent) reload() error {
+	if cmp.preReload != nil {
+		cmp.preReload(cmp.cfg)
+	}
+	// Shutdown server
+	closer := getCloser(cmp.cfg, cmp.name)
+	if closer != nil {
+		closer.fn()
+	}
+	// Cleanup
+	delCloser(cmp.cfg, cmp.name)
+	delWorker(cmp.cfg, cmp.name)
+	// Init server with new parameters
+	cmp.init(cmp.cfg)
+	// Start worker
+	if cmp.enabled {
+		startWorker(cmp.cfg, *getWorker(cmp.cfg, cmp.name))
+	}
+	return nil
+}

cmd/frostfs-node/main.go

@@ -81,8 +81,10 @@ func initApp(c *cfg) {
 		c.wg.Done()
 	}()
 
-	initAndLog(c, "pprof", initProfiler)
-	initAndLog(c, "prometheus", initMetrics)
+	pprof, _ := pprofComponent(c)
+	metrics, _ := metricsComponent(c)
+	initAndLog(c, pprof.name, pprof.init)
+	initAndLog(c, metrics.name, metrics.init)
 
 	initLocalStorage(c)
 
@@ -114,6 +116,19 @@ func runAndLog(c *cfg, name string, logSuccess bool, starter func(*cfg)) {
 	}
 }
 
+func stopAndLog(c *cfg, name string, stopper func() error) {
+	c.log.Debug(fmt.Sprintf("shutting down %s service", name))
+
+	err := stopper()
+	if err != nil {
+		c.log.Debug(fmt.Sprintf("could not shutdown %s server", name),
+			zap.String("error", err.Error()),
+		)
+	}
+
+	c.log.Debug(fmt.Sprintf("%s service has been stopped", name))
+}
+
 func bootUp(c *cfg) {
 	runAndLog(c, "NATS", true, connectNats)
 	runAndLog(c, "gRPC", false, serveGRPC)
@@ -135,5 +150,5 @@ func wait(c *cfg) {
 }
 
 func (c *cfg) onShutdown(f func()) {
-	c.closers = append(c.closers, f)
+	c.closers = append(c.closers, closer{"", f})
 }

cmd/frostfs-node/metrics.go

@@ -1,47 +1,45 @@
 package main
 
 import (
-	"context"
-
 	metricsconfig "github.com/TrueCloudLab/frostfs-node/cmd/frostfs-node/config/metrics"
-	httputil "github.com/TrueCloudLab/frostfs-node/pkg/util/http"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
-	"go.uber.org/zap"
 )
 
-func initMetrics(c *cfg) {
-	if !metricsconfig.Enabled(c.appCfg) {
-		c.log.Info("prometheus is disabled")
-		return
+func metricsComponent(c *cfg) (*httpComponent, bool) {
+	var updated bool
+	// check if it has been inited before
+	if c.dynamicConfiguration.metrics == nil {
+		c.dynamicConfiguration.metrics = new(httpComponent)
+		c.dynamicConfiguration.metrics.cfg = c
+		c.dynamicConfiguration.metrics.name = "metrics"
+		c.dynamicConfiguration.metrics.handler = promhttp.Handler()
+		updated = true
 	}
 
-	var prm httputil.Prm
+	// (re)init read configuration
+	enabled := metricsconfig.Enabled(c.appCfg)
+	if enabled != c.dynamicConfiguration.metrics.enabled {
+		c.dynamicConfiguration.metrics.enabled = enabled
+		updated = true
+	}
+	address := metricsconfig.Address(c.appCfg)
+	if address != c.dynamicConfiguration.metrics.address {
+		c.dynamicConfiguration.metrics.address = address
+		updated = true
+	}
+	dur := metricsconfig.ShutdownTimeout(c.appCfg)
+	if dur != c.dynamicConfiguration.metrics.shutdownDur {
+		c.dynamicConfiguration.metrics.shutdownDur = dur
+		updated = true
+	}
 
-	prm.Address = metricsconfig.Address(c.appCfg)
-	prm.Handler = promhttp.Handler()
-
-	srv := httputil.New(prm,
-		httputil.WithShutdownTimeout(
-			metricsconfig.ShutdownTimeout(c.appCfg),
-		),
-	)
-
-	c.workers = append(c.workers, newWorkerFromFunc(func(context.Context) {
-		runAndLog(c, "metrics", false, func(c *cfg) {
-			fatalOnErr(srv.Serve())
-		})
-	}))
-
-	c.closers = append(c.closers, func() {
-		c.log.Debug("shutting down metrics service")
-
-		err := srv.Shutdown()
-		if err != nil {
-			c.log.Debug("could not shutdown metrics server",
-				zap.String("error", err.Error()),
-			)
-		}
-
-		c.log.Debug("metrics service has been stopped")
-	})
+	return c.dynamicConfiguration.metrics, updated
+}
+
+func enableMetricsSvc(c *cfg) {
+	c.shared.metricsSvc.Enable()
+}
+
+func disableMetricsSvc(c *cfg) {
+	c.shared.metricsSvc.Disable()
 }

cmd/frostfs-node/object.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/TrueCloudLab/frostfs-api-go/v2/object"
 	objectGRPC "github.com/TrueCloudLab/frostfs-api-go/v2/object/grpc"
+	metricsconfig "github.com/TrueCloudLab/frostfs-node/cmd/frostfs-node/config/metrics"
 	policerconfig "github.com/TrueCloudLab/frostfs-node/cmd/frostfs-node/config/policer"
 	replicatorconfig "github.com/TrueCloudLab/frostfs-node/cmd/frostfs-node/config/replicator"
 	coreclient "github.com/TrueCloudLab/frostfs-node/pkg/core/client"
@@ -246,7 +247,11 @@ func initObjectService(c *cfg) {
 
 	traverseGen := util.NewTraverserGenerator(c.netMapSource, c.cfgObject.cnrSource, c)
 
-	c.workers = append(c.workers, pol)
+	c.workers = append(c.workers, worker{
+		fn: func(ctx context.Context) {
+			pol.Run(ctx)
+		},
+	})
 
 	var os putsvc.ObjectStorage = engineWithoutNotifications{
 		engine: ls,
@@ -380,12 +385,9 @@ func initObjectService(c *cfg) {
 		respSvc,
 	)
 
-	var firstSvc objectService.ServiceServer = signSvc
-	if c.metricsCollector != nil {
-		firstSvc = objectService.NewMetricCollector(signSvc, c.metricsCollector)
-	}
-
-	server := objectTransportGRPC.New(firstSvc)
+	c.shared.metricsSvc = objectService.NewMetricCollector(
+		signSvc, c.metricsCollector, metricsconfig.Enabled(c.appCfg))
+	server := objectTransportGRPC.New(c.shared.metricsSvc)
 
 	for _, srv := range c.cfgGRPC.servers {
 		objectGRPC.RegisterObjectServiceServer(srv, server)

cmd/frostfs-node/pprof.go

@@ -1,46 +1,37 @@
 package main
 
 import (
-	"context"
-
 	profilerconfig "github.com/TrueCloudLab/frostfs-node/cmd/frostfs-node/config/profiler"
 	httputil "github.com/TrueCloudLab/frostfs-node/pkg/util/http"
-	"go.uber.org/zap"
 )
 
-func initProfiler(c *cfg) {
-	if !profilerconfig.Enabled(c.appCfg) {
-		c.log.Info("pprof is disabled")
-		return
+func pprofComponent(c *cfg) (*httpComponent, bool) {
+	var updated bool
+	// check if it has been inited before
+	if c.dynamicConfiguration.pprof == nil {
+		c.dynamicConfiguration.pprof = new(httpComponent)
+		c.dynamicConfiguration.pprof.cfg = c
+		c.dynamicConfiguration.pprof.name = "pprof"
+		c.dynamicConfiguration.pprof.handler = httputil.Handler()
+		updated = true
 	}
 
-	var prm httputil.Prm
+	// (re)init read configuration
+	enabled := profilerconfig.Enabled(c.appCfg)
+	if enabled != c.dynamicConfiguration.pprof.enabled {
+		c.dynamicConfiguration.pprof.enabled = enabled
+		updated = true
+	}
+	address := profilerconfig.Address(c.appCfg)
+	if address != c.dynamicConfiguration.pprof.address {
+		c.dynamicConfiguration.pprof.address = address
+		updated = true
+	}
+	dur := profilerconfig.ShutdownTimeout(c.appCfg)
+	if dur != c.dynamicConfiguration.pprof.shutdownDur {
+		c.dynamicConfiguration.pprof.shutdownDur = dur
+		updated = true
+	}
 
-	prm.Address = profilerconfig.Address(c.appCfg)
-	prm.Handler = httputil.Handler()
-
-	srv := httputil.New(prm,
-		httputil.WithShutdownTimeout(
-			profilerconfig.ShutdownTimeout(c.appCfg),
-		),
-	)
-
-	c.workers = append(c.workers, newWorkerFromFunc(func(context.Context) {
-		runAndLog(c, "profiler", false, func(c *cfg) {
-			fatalOnErr(srv.Serve())
-		})
-	}))
-
-	c.closers = append(c.closers, func() {
-		c.log.Debug("shutting down profiling service")
-
-		err := srv.Shutdown()
-		if err != nil {
-			c.log.Debug("could not shutdown pprof server",
-				zap.String("error", err.Error()),
-			)
-		}
-
-		c.log.Debug("profiling service has been stopped")
-	})
+	return c.dynamicConfiguration.pprof, updated
 }

cmd/frostfs-node/worker.go

@@ -4,31 +4,46 @@ import (
 	"context"
 )
 
-type worker interface {
-	Run(context.Context)
-}
-
-type workerFromFunc struct {
-	fn func(context.Context)
+type worker struct {
+	name string
+	fn   func(context.Context)
 }
 
 func newWorkerFromFunc(fn func(ctx context.Context)) worker {
-	return &workerFromFunc{
+	return worker{
 		fn: fn,
 	}
 }
 
-func (w *workerFromFunc) Run(ctx context.Context) {
-	w.fn(ctx)
-}
-
 func startWorkers(c *cfg) {
 	for _, wrk := range c.workers {
-		c.wg.Add(1)
-
-		go func(w worker) {
-			w.Run(c.ctx)
-			c.wg.Done()
-		}(wrk)
+		startWorker(c, wrk)
 	}
 }
+
+func startWorker(c *cfg, wrk worker) {
+	c.wg.Add(1)
+
+	go func(w worker) {
+		w.fn(c.ctx)
+		c.wg.Done()
+	}(wrk)
+}
+
+func delWorker(c *cfg, name string) {
+	for i, worker := range c.workers {
+		if worker.name == name {
+			c.workers = append(c.workers[:i], c.workers[i+1:]...)
+			return
+		}
+	}
+}
+
+func getWorker(c *cfg, name string) *worker {
+	for _, wrk := range c.workers {
+		if wrk.name == name {
+			return &wrk
+		}
+	}
+	return nil
+}

pkg/services/object/metrics.go

@@ -12,6 +12,7 @@ type (
 	MetricCollector struct {
 		next    ServiceServer
 		metrics MetricRegister
+		enabled bool
 	}
 
 	getStreamMetric struct {
@@ -48,96 +49,125 @@ type (
 	}
 )
 
-func NewMetricCollector(next ServiceServer, register MetricRegister) *MetricCollector {
+func NewMetricCollector(next ServiceServer, register MetricRegister, enabled bool) *MetricCollector {
 	return &MetricCollector{
 		next:    next,
 		metrics: register,
+		enabled: enabled,
 	}
 }
 
 func (m MetricCollector) Get(req *object.GetRequest, stream GetObjectStream) (err error) {
-	t := time.Now()
-	defer func() {
-		m.metrics.IncGetReqCounter(err == nil)
-		m.metrics.AddGetReqDuration(time.Since(t))
-	}()
-
-	err = m.next.Get(req, &getStreamMetric{
-		ServerStream: stream,
-		stream:       stream,
-		metrics:      m.metrics,
-	})
+	if m.enabled {
+		t := time.Now()
+		defer func() {
+			m.metrics.IncGetReqCounter(err == nil)
+			m.metrics.AddGetReqDuration(time.Since(t))
+		}()
+		err = m.next.Get(req, &getStreamMetric{
+			ServerStream: stream,
+			stream:       stream,
+			metrics:      m.metrics,
+		})
+	} else {
+		err = m.next.Get(req, stream)
+	}
 	return
 }
 
 func (m MetricCollector) Put(ctx context.Context) (PutObjectStream, error) {
-	t := time.Now()
+	if m.enabled {
+		t := time.Now()
 
-	stream, err := m.next.Put(ctx)
-	if err != nil {
-		return nil, err
+		stream, err := m.next.Put(ctx)
+		if err != nil {
+			return nil, err
+		}
+
+		return &putStreamMetric{
+			stream:  stream,
+			metrics: m.metrics,
+			start:   t,
+		}, nil
 	}
-
-	return &putStreamMetric{
-		stream:  stream,
-		metrics: m.metrics,
-		start:   t,
-	}, nil
+	return m.next.Put(ctx)
 }
 
 func (m MetricCollector) Head(ctx context.Context, request *object.HeadRequest) (*object.HeadResponse, error) {
-	t := time.Now()
+	if m.enabled {
+		t := time.Now()
 
-	res, err := m.next.Head(ctx, request)
+		res, err := m.next.Head(ctx, request)
 
-	m.metrics.IncHeadReqCounter(err == nil)
-	m.metrics.AddHeadReqDuration(time.Since(t))
+		m.metrics.IncHeadReqCounter(err == nil)
+		m.metrics.AddHeadReqDuration(time.Since(t))
 
-	return res, err
+		return res, err
+	}
+	return m.next.Head(ctx, request)
 }
 
 func (m MetricCollector) Search(req *object.SearchRequest, stream SearchStream) error {
-	t := time.Now()
+	if m.enabled {
+		t := time.Now()
 
-	err := m.next.Search(req, stream)
+		err := m.next.Search(req, stream)
 
-	m.metrics.IncSearchReqCounter(err == nil)
-	m.metrics.AddSearchReqDuration(time.Since(t))
+		m.metrics.IncSearchReqCounter(err == nil)
+		m.metrics.AddSearchReqDuration(time.Since(t))
 
-	return err
+		return err
+	}
+	return m.next.Search(req, stream)
 }
 
 func (m MetricCollector) Delete(ctx context.Context, request *object.DeleteRequest) (*object.DeleteResponse, error) {
-	t := time.Now()
+	if m.enabled {
+		t := time.Now()
 
-	res, err := m.next.Delete(ctx, request)
+		res, err := m.next.Delete(ctx, request)
 
-	m.metrics.IncDeleteReqCounter(err == nil)
-	m.metrics.AddDeleteReqDuration(time.Since(t))
-
-	return res, err
+		m.metrics.IncDeleteReqCounter(err == nil)
+		m.metrics.AddDeleteReqDuration(time.Since(t))
+		return res, err
+	}
+	return m.next.Delete(ctx, request)
 }
 
 func (m MetricCollector) GetRange(req *object.GetRangeRequest, stream GetObjectRangeStream) error {
-	t := time.Now()
+	if m.enabled {
+		t := time.Now()
 
-	err := m.next.GetRange(req, stream)
+		err := m.next.GetRange(req, stream)
 
-	m.metrics.IncRangeReqCounter(err == nil)
-	m.metrics.AddRangeReqDuration(time.Since(t))
+		m.metrics.IncRangeReqCounter(err == nil)
+		m.metrics.AddRangeReqDuration(time.Since(t))
 
-	return err
+		return err
+	}
+	return m.next.GetRange(req, stream)
 }
 
 func (m MetricCollector) GetRangeHash(ctx context.Context, request *object.GetRangeHashRequest) (*object.GetRangeHashResponse, error) {
-	t := time.Now()
+	if m.enabled {
+		t := time.Now()
 
-	res, err := m.next.GetRangeHash(ctx, request)
+		res, err := m.next.GetRangeHash(ctx, request)
 
-	m.metrics.IncRangeHashReqCounter(err == nil)
-	m.metrics.AddRangeHashReqDuration(time.Since(t))
+		m.metrics.IncRangeHashReqCounter(err == nil)
+		m.metrics.AddRangeHashReqDuration(time.Since(t))
 
-	return res, err
+		return res, err
+	}
+	return m.next.GetRangeHash(ctx, request)
+}
+
+func (m *MetricCollector) Enable() {
+	m.enabled = true
+}
+
+func (m *MetricCollector) Disable() {
+	m.enabled = false
 }
 
 func (s getStreamMetric) Send(resp *object.GetResponse) error {

pkg/util/http/server.go

@@ -6,12 +6,12 @@ import (
 	"time"
 )
 
-// Prm groups the required parameters of the Server's constructor.
+// HTTPSrvPrm groups the required parameters of the Server's constructor.
 //
 // All values must comply with the requirements imposed on them.
 // Passing incorrect parameter values will result in constructor
 // failure (error or panic depending on the implementation).
-type Prm struct {
+type HTTPSrvPrm struct {
 	// TCP address for the server to listen on.
 	//
 	// Must be a valid TCP address.
@@ -49,6 +49,15 @@ func panicOnValue(t, n string, v interface{}) {
 	panic(fmt.Sprintf(invalidValFmt, t, n, v, v))
 }
 
+func checkSrvPrm(addr string, handler http.Handler) {
+	switch {
+	case addr == "":
+		panicOnPrmValue("Address", addr)
+	case handler == nil:
+		panicOnPrmValue("Handler", handler)
+	}
+}
+
 // New creates a new instance of the Server.
 //
 // Panics if at least one value of the parameters is invalid.
@@ -58,13 +67,8 @@ func panicOnValue(t, n string, v interface{}) {
 //
 // The created Server does not require additional
 // initialization and is completely ready for work.
-func New(prm Prm, opts ...Option) *Server {
-	switch {
-	case prm.Address == "":
-		panicOnPrmValue("Address", prm.Address)
-	case prm.Handler == nil:
-		panicOnPrmValue("Handler", prm.Handler)
-	}
+func New(prm HTTPSrvPrm, opts ...Option) *Server {
+	checkSrvPrm(prm.Address, prm.Handler)
 
 	c := defaultCfg()
 
@@ -85,3 +89,14 @@ func New(prm Prm, opts ...Option) *Server {
 		},
 	}
 }
+
+// NewHTTPSrvPrm creates a new instance of the HTTPSrvPrm.
+//
+// Panics if at least one value of the parameters is invalid.
+func NewHTTPSrvPrm(addr string, handler http.Handler) *HTTPSrvPrm {
+	checkSrvPrm(addr, handler)
+	return &HTTPSrvPrm{
+		Address: addr,
+		Handler: handler,
+	}
+}