[#493] Refactor serving of prometheus and pprof services

Rename `util/profiler` package to `httputil` and refactor it:

  * simplify utility HTTP server;

  * make more generic server's parameters in order to remove `viper.Viper`
    dependency;

  * use single constructor for creating the pprof and prometheus servers;

  * replace `enabled` config value with empty-check of the network address.

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

cmd/neofs-ir/defaults.go

@@ -32,13 +32,9 @@ func newConfig(path string) (*viper.Viper, error) {
 func defaultConfiguration(cfg *viper.Viper) {
 	cfg.SetDefault("logger.level", "info")
 
-	cfg.SetDefault("pprof.enabled", false)
-	cfg.SetDefault("pprof.address", ":6060")
-	cfg.SetDefault("pprof.shutdown_ttl", "30s")
+	cfg.SetDefault("profiler.shutdown_timeout", "30s")
 
-	cfg.SetDefault("metrics.enabled", false)
-	cfg.SetDefault("metrics.address", ":9090")
-	cfg.SetDefault("metrics.shutdown_ttl", "30s")
+	cfg.SetDefault("metrics.shutdown_timeout", "30s")
 
 	cfg.SetDefault("without_mainnet", false)
 	cfg.SetDefault("without_notary", false)

cmd/neofs-ir/main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"flag"
 	"fmt"
+	"net/http"
 	"os"
 	"strings"
 
@@ -10,8 +11,9 @@ import (
 	"github.com/nspcc-dev/neofs-node/misc"
 	"github.com/nspcc-dev/neofs-node/pkg/innerring"
 	"github.com/nspcc-dev/neofs-node/pkg/util/grace"
+	httputil "github.com/nspcc-dev/neofs-node/pkg/util/http"
 	"github.com/nspcc-dev/neofs-node/pkg/util/logger"
-	"github.com/nspcc-dev/neofs-node/pkg/util/profiler"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"go.uber.org/zap"
 )
 
@@ -57,8 +59,33 @@ func main() {
 	ctx := grace.NewGracefulContext(log)
 	intErr := make(chan error) // internal inner ring errors
 
-	pprof := profiler.NewProfiler(log, cfg)
-	prometheus := profiler.NewMetrics(log, cfg)
+	var httpServers []*httputil.Server
+
+	for _, item := range []struct {
+		cfgPrefix string
+		handler   func() http.Handler
+	}{
+		{"profiler", httputil.Handler},
+		{"metrics", promhttp.Handler},
+	} {
+		addr := cfg.GetString(item.cfgPrefix + ".address")
+		if addr == "" {
+			continue
+		}
+
+		var prm httputil.Prm
+
+		prm.Address = addr
+		prm.Handler = item.handler()
+
+		httpServers = append(httpServers,
+			httputil.New(prm,
+				httputil.WithShutdownTimeout(
+					cfg.GetDuration(item.cfgPrefix+".shutdown_timeout"),
+				),
+			),
+		)
+	}
 
 	innerRing, err := innerring.New(ctx, log, cfg)
 	if err != nil {
@@ -75,16 +102,12 @@ func main() {
 		return
 	}
 
-	// start pprof if enabled
-	if pprof != nil {
-		pprof.Start(ctx)
-		defer pprof.Stop()
-	}
-
-	// start prometheus if enabled
-	if prometheus != nil {
-		prometheus.Start(ctx)
-		defer prometheus.Stop()
+	// start HTTP servers
+	for i := range httpServers {
+		srv := httpServers[i]
+		go func() {
+			exitErr(srv.Serve())
+		}()
 	}
 
 	// start inner ring
@@ -108,6 +131,20 @@ func main() {
 
 	innerRing.Stop()
 
+	// shut down HTTP servers
+	for i := range httpServers {
+		srv := httpServers[i]
+
+		go func() {
+			err := srv.Shutdown()
+			if err != nil {
+				log.Debug("could not shutdown HTTP server",
+					zap.String("error", err.Error()),
+				)
+			}
+		}()
+	}
+
 	log.Info("application stopped")
 }
 

cmd/neofs-node/config.go

@@ -40,7 +40,6 @@ import (
 	"github.com/nspcc-dev/neofs-node/pkg/services/util/response"
 	util2 "github.com/nspcc-dev/neofs-node/pkg/util"
 	"github.com/nspcc-dev/neofs-node/pkg/util/logger"
-	"github.com/nspcc-dev/neofs-node/pkg/util/profiler"
 	"github.com/panjf2000/ants/v2"
 	"github.com/pkg/errors"
 	"github.com/spf13/viper"
@@ -55,13 +54,12 @@ const (
 	cfgLogLevel = "logger.level"
 
 	// pprof keys
-	cfgProfilerEnable = "pprof.enabled"
-	cfgProfilerAddr   = "pprof.address"
-	cfgProfilerTTL    = "pprof.shutdown_ttl"
+	cfgProfilerAddr            = "profiler.address"
+	cfgProfilerShutdownTimeout = "profiler.shutdown_timeout"
 
 	// metrics keys
-	cfgMetricsEnable = "metrics.enabled"
 	cfgMetricsAddr            = "metrics.address"
+	cfgMetricsShutdownTimeout = "metrics.shutdown_timeout"
 
 	// config keys for cfgNodeInfo
 	cfgNodeKey             = "node.key"
@@ -203,10 +201,6 @@ type cfg struct {
 
 	cfgObject cfgObject
 
-	profiler profiler.Profiler
-
-	metricsServer profiler.Metrics
-
 	metricsCollector *metrics.StorageMetrics
 
 	workers []worker
@@ -438,7 +432,7 @@ func initCfg(path string) *cfg {
 		},
 	}
 
-	if viperCfg.GetBool(cfgMetricsEnable) {
+	if c.viper.GetString(cfgMetricsAddr) != "" {
 		c.metricsCollector = metrics.NewStorageMetrics()
 	}
 
@@ -496,12 +490,9 @@ func defaultConfiguration(v *viper.Viper) {
 
 	v.SetDefault(cfgLogLevel, "info")
 
-	v.SetDefault(cfgProfilerEnable, false)
-	v.SetDefault(cfgProfilerAddr, ":6060")
-	v.SetDefault(cfgProfilerTTL, "30s")
+	v.SetDefault(cfgProfilerShutdownTimeout, "30s")
 
-	v.SetDefault(cfgMetricsEnable, false)
-	v.SetDefault(cfgMetricsAddr, ":9090")
+	v.SetDefault(cfgMetricsShutdownTimeout, "30s")
 
 	v.SetDefault(cfgGCQueueSize, 1000)
 	v.SetDefault(cfgGCQueueTick, "5s")

cmd/neofs-node/main.go

@@ -60,12 +60,10 @@ func initApp(c *cfg) {
 }
 
 func bootUp(c *cfg) {
-	serveProfiler(c)
 	serveGRPC(c)
 	bootstrapNode(c)
 	startWorkers(c)
 	startBlockTimers(c)
-	serveMetrics(c)
 }
 
 func wait(c *cfg) {

cmd/neofs-node/metrics.go

@@ -1,17 +1,40 @@
 package main
 
 import (
-	"github.com/nspcc-dev/neofs-node/pkg/util/profiler"
+	"context"
+
+	httputil "github.com/nspcc-dev/neofs-node/pkg/util/http"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"go.uber.org/zap"
 )
 
 func initMetrics(c *cfg) {
-	if c.metricsCollector != nil {
-		c.metricsServer = profiler.NewMetrics(c.log, c.viper)
+	addr := c.viper.GetString(cfgMetricsAddr)
+	if addr == "" {
+		return
 	}
-}
 
-func serveMetrics(c *cfg) {
-	if c.metricsServer != nil {
-		c.metricsServer.Start(c.ctx)
+	var prm httputil.Prm
+
+	prm.Address = addr
+	prm.Handler = promhttp.Handler()
+
+	srv := httputil.New(prm,
+		httputil.WithShutdownTimeout(
+			c.viper.GetDuration(cfgMetricsShutdownTimeout),
+		),
+	)
+
+	c.workers = append(c.workers, newWorkerFromFunc(func(context.Context) {
+		fatalOnErr(srv.Serve())
+	}))
+
+	c.closers = append(c.closers, func() {
+		err := srv.Shutdown()
+		if err != nil {
+			c.log.Debug("could not shutdown metrics server",
+				zap.String("error", err.Error()),
+			)
 		}
+	})
 }

cmd/neofs-node/pprof.go

@@ -1,15 +1,39 @@
 package main
 
 import (
-	"github.com/nspcc-dev/neofs-node/pkg/util/profiler"
+	"context"
+
+	httputil "github.com/nspcc-dev/neofs-node/pkg/util/http"
+	"go.uber.org/zap"
 )
 
 func initProfiler(c *cfg) {
-	c.profiler = profiler.NewProfiler(c.log, c.viper)
-}
-
-func serveProfiler(c *cfg) {
-	if c.profiler != nil {
-		c.profiler.Start(c.ctx)
+	addr := c.viper.GetString(cfgProfilerAddr)
+	if addr == "" {
+		return
 	}
+
+	var prm httputil.Prm
+
+	prm.Address = addr
+	prm.Handler = httputil.Handler()
+
+	srv := httputil.New(prm,
+		httputil.WithShutdownTimeout(
+			c.viper.GetDuration(cfgProfilerShutdownTimeout),
+		),
+	)
+
+	c.workers = append(c.workers, newWorkerFromFunc(func(context.Context) {
+		fatalOnErr(srv.Serve())
+	}))
+
+	c.closers = append(c.closers, func() {
+		err := srv.Shutdown()
+		if err != nil {
+			c.log.Debug("could not shutdown pprof server",
+				zap.String("error", err.Error()),
+			)
+		}
+	})
 }

pkg/util/http/calls.go

@@ -0,0 +1,44 @@
+package httputil
+
+import (
+	"context"
+	"net/http"
+
+	"github.com/pkg/errors"
+)
+
+// Serve listens and serves internal HTTP server.
+//
+// Returns any error returned by internal server
+// except http.ErrServerClosed.
+//
+// After Shutdown call, Serve has no effect and
+// returned error is always nil.
+func (x *Server) Serve() error {
+	err := x.srv.ListenAndServe()
+
+	// http.ErrServerClosed is returned on server shutdown
+	// so we ignore this error.
+	if err != nil && errors.Is(err, http.ErrServerClosed) {
+		err = nil
+	}
+
+	return err
+}
+
+// Shutdown gracefully shuts down internal HTTP server.
+//
+// Shutdown is called with context which expires after
+// configured timeout.
+//
+// Once Shutdown has been called on a server, it may not be reused;
+// future calls to Serve method will have no effect.
+func (x *Server) Shutdown() error {
+	ctx, cancel := context.WithTimeout(context.Background(), x.shutdownTimeout)
+
+	err := x.srv.Shutdown(ctx)
+
+	cancel()
+
+	return err
+}

pkg/util/http/opts.go

@@ -0,0 +1,26 @@
+package httputil
+
+import (
+	"time"
+)
+
+// Option sets an optional parameter of Server.
+type Option func(*cfg)
+
+type cfg struct {
+	shutdownTimeout time.Duration
+}
+
+func defaultCfg() *cfg {
+	return &cfg{
+		shutdownTimeout: 15 * time.Second,
+	}
+}
+
+// WithShutdownTimeout returns option to set shutdown timeout
+// of the internal HTTP server.
+func WithShutdownTimeout(dur time.Duration) Option {
+	return func(c *cfg) {
+		c.shutdownTimeout = dur
+	}
+}

pkg/util/http/pprof.go

@@ -0,0 +1,16 @@
+package httputil
+
+import (
+	"net/http"
+	"net/http/pprof"
+)
+
+// initializes pprof package in order to
+// register Prometheus handlers on http.DefaultServeMux.
+var _ = pprof.Handler("")
+
+// Handler returns http.Handler for the
+// Prometheus metrics collector.
+func Handler() http.Handler {
+	return http.DefaultServeMux
+}

pkg/util/http/server.go

@@ -0,0 +1,87 @@
+package httputil
+
+import (
+	"fmt"
+	"net/http"
+	"time"
+)
+
+// Prm 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 {
+	// TCP address for the server to listen on.
+	//
+	// Must be a valid TCP address.
+	Address string
+
+	// Must not be nil.
+	Handler http.Handler
+}
+
+// Server represents a wrapper over http.Server
+// that provides interface to start and stop
+// listening routine.
+//
+// For correct operation, Server must be created
+// using the constructor (New) based on the required parameters
+// and optional components. After successful creation,
+// Server is immediately ready to work through API.
+type Server struct {
+	shutdownTimeout time.Duration
+
+	srv *http.Server
+}
+
+const invalidValFmt = "invalid %s %s (%T): %v"
+
+func panicOnPrmValue(n string, v interface{}) {
+	panicOnValue("parameter", n, v)
+}
+
+func panicOnOptValue(n string, v interface{}) {
+	panicOnValue("option", n, v)
+}
+
+func panicOnValue(t, n string, v interface{}) {
+	panic(fmt.Sprintf(invalidValFmt, t, n, v, v))
+}
+
+// New creates a new instance of the Server.
+//
+// Panics if at least one value of the parameters is invalid.
+//
+// Panics if at least one of next optinal parameters is invalid:
+//  * shutdown timeout is non-positive.
+//
+// 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)
+	}
+
+	c := defaultCfg()
+
+	for _, o := range opts {
+		o(c)
+	}
+
+	switch {
+	case c.shutdownTimeout <= 0:
+		panicOnOptValue("shutdown timeout", c.shutdownTimeout)
+	}
+
+	return &Server{
+		shutdownTimeout: c.shutdownTimeout,
+		srv: &http.Server{
+			Addr:    prm.Address,
+			Handler: prm.Handler,
+		},
+	}
+}

pkg/util/profiler/http.go

@@ -1,114 +0,0 @@
-package profiler
-
-import (
-	"context"
-	"net/http"
-	"sync/atomic"
-	"time"
-
-	"github.com/spf13/viper"
-	"go.uber.org/zap"
-)
-
-type (
-	httpParams struct {
-		Key     string
-		Viper   *viper.Viper
-		Logger  *zap.Logger
-		Handler http.Handler
-	}
-
-	httpServer struct {
-		name        string
-		started     *int32
-		logger      *zap.Logger
-		shutdownTTL time.Duration
-		server      server
-	}
-)
-
-func (h *httpServer) Start(ctx context.Context) {
-	if h == nil {
-		return
-	}
-
-	if !atomic.CompareAndSwapInt32(h.started, 0, 1) {
-		h.logger.Info("http: already started",
-			zap.String("server", h.name))
-		return
-	}
-
-	go func() {
-		if err := h.server.serve(ctx); err != nil {
-			if err != http.ErrServerClosed {
-				h.logger.Error("http: could not start server",
-					zap.Error(err))
-			}
-		}
-	}()
-}
-
-func (h *httpServer) Stop() {
-	if h == nil {
-		return
-	}
-
-	if !atomic.CompareAndSwapInt32(h.started, 1, 0) {
-		h.logger.Info("http: already stopped",
-			zap.String("server", h.name))
-		return
-	}
-
-	ctx, cancel := context.WithTimeout(context.Background(), h.shutdownTTL)
-	defer cancel()
-
-	h.logger.Debug("http: try to stop server",
-		zap.String("server", h.name))
-
-	if err := h.server.shutdown(ctx); err != nil {
-		h.logger.Error("http: could not stop server",
-			zap.Error(err))
-	}
-}
-
-const defaultShutdownTTL = 30 * time.Second
-
-func newHTTPServer(p httpParams) *httpServer {
-	var (
-		address  string
-		shutdown time.Duration
-	)
-
-	if address = p.Viper.GetString(p.Key + ".address"); address == "" {
-		p.Logger.Info("Empty bind address, skip",
-			zap.String("server", p.Key))
-		return nil
-	}
-	if p.Handler == nil {
-		p.Logger.Info("Empty handler, skip",
-			zap.String("server", p.Key))
-		return nil
-	}
-
-	p.Logger.Info("Create http.Server",
-		zap.String("server", p.Key),
-		zap.String("address", address))
-
-	if shutdown = p.Viper.GetDuration(p.Key + ".shutdown_ttl"); shutdown <= 0 {
-		shutdown = defaultShutdownTTL
-	}
-
-	return &httpServer{
-		name:        p.Key,
-		started:     new(int32),
-		logger:      p.Logger,
-		shutdownTTL: shutdown,
-		server: newServer(params{
-			Address: address,
-			Name:    p.Key,
-			Config:  p.Viper,
-			Logger:  p.Logger,
-			Handler: p.Handler,
-		}),
-	}
-}

pkg/util/profiler/metrics.go

@@ -1,32 +0,0 @@
-package profiler
-
-import (
-	"context"
-
-	"github.com/prometheus/client_golang/prometheus/promhttp"
-	"github.com/spf13/viper"
-	"go.uber.org/zap"
-)
-
-// Metrics is an interface of metric tool.
-type Metrics interface {
-	Start(ctx context.Context)
-	Stop()
-}
-
-const metricsKey = "metrics"
-
-// NewMetrics is a metric tool's constructor.
-func NewMetrics(l *zap.Logger, v *viper.Viper) Metrics {
-	if !v.GetBool(metricsKey + ".enabled") {
-		l.Debug("metrics server disabled")
-		return nil
-	}
-
-	return newHTTPServer(httpParams{
-		Key:     metricsKey,
-		Viper:   v,
-		Logger:  l,
-		Handler: promhttp.Handler(),
-	})
-}

pkg/util/profiler/pprof.go

@@ -1,44 +0,0 @@
-package profiler
-
-import (
-	"context"
-	"expvar"
-	"net/http"
-	"net/http/pprof"
-
-	"github.com/spf13/viper"
-	"go.uber.org/zap"
-)
-
-// Profiler is an interface of profiler.
-type Profiler interface {
-	Start(ctx context.Context)
-	Stop()
-}
-
-const profilerKey = "pprof"
-
-// NewProfiler is a profiler's constructor.
-func NewProfiler(l *zap.Logger, v *viper.Viper) Profiler {
-	if !v.GetBool(profilerKey + ".enabled") {
-		l.Debug("pprof server disabled")
-		return nil
-	}
-
-	mux := http.NewServeMux()
-
-	mux.Handle("/debug/vars", expvar.Handler())
-
-	mux.HandleFunc("/debug/pprof/", pprof.Index)
-	mux.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
-	mux.HandleFunc("/debug/pprof/profile", pprof.Profile)
-	mux.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
-	mux.HandleFunc("/debug/pprof/trace", pprof.Trace)
-
-	return newHTTPServer(httpParams{
-		Key:     profilerKey,
-		Viper:   v,
-		Logger:  l,
-		Handler: mux,
-	})
-}

pkg/util/profiler/server.go

@@ -1,62 +0,0 @@
-package profiler
-
-import (
-	"context"
-	"net/http"
-
-	"github.com/spf13/viper"
-	"go.uber.org/zap"
-)
-
-type (
-	// Server is an interface of server.
-	server interface {
-		serve(ctx context.Context) error
-		shutdown(ctx context.Context) error
-	}
-
-	contextServer struct {
-		logger *zap.Logger
-		server *http.Server
-	}
-
-	params struct {
-		Address string
-		Name    string
-		Config  *viper.Viper
-		Logger  *zap.Logger
-		Handler http.Handler
-	}
-)
-
-func newServer(p params) server {
-	return &contextServer{
-		logger: p.Logger,
-		server: &http.Server{
-			Addr:              p.Address,
-			Handler:           p.Handler,
-			ReadTimeout:       p.Config.GetDuration(p.Name + ".read_timeout"),
-			ReadHeaderTimeout: p.Config.GetDuration(p.Name + ".read_header_timeout"),
-			WriteTimeout:      p.Config.GetDuration(p.Name + ".write_timeout"),
-			IdleTimeout:       p.Config.GetDuration(p.Name + ".idle_timeout"),
-			MaxHeaderBytes:    p.Config.GetInt(p.Name + ".max_header_bytes"),
-		},
-	}
-}
-
-func (cs *contextServer) serve(ctx context.Context) error {
-	go func() {
-		<-ctx.Done()
-
-		if err := cs.server.Close(); err != nil {
-			cs.logger.Info("something went wrong",
-				zap.Error(err))
-		}
-	}()
-
-	return cs.server.ListenAndServe()
-}
-
-func (cs *contextServer) shutdown(ctx context.Context) error {
-	return cs.server.Shutdown(ctx)
-}