[FAB-6558]Make metrics option configurable

This patchset make metrics option configurable
based core.yaml. Meanwhile refactor metrics
server create and start separate. Add a no-op
metrics implementation when metrics disabled
in config.

Change-Id: Ic4a1cc769cf3dd93a545a3cd1d938585708abf4a
Signed-off-by: grapebaba <281165273@qq.com>

common/metrics/server.go

@@ -0,0 +1,209 @@
+/*
+Copyright IBM Corp. All Rights Reserved.
+
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package metrics
+
+import (
+	"fmt"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"github.com/spf13/viper"
+	"github.com/uber-go/tally"
+)
+
+const (
+	namespace string = "hyperledger_fabric"
+
+	statsdReporterType = "statsd"
+	promReporterType   = "prom"
+
+	defaultReporterType = statsdReporterType
+	defaultInterval     = 1 * time.Second
+
+	defaultStatsdReporterFlushInterval = 2 * time.Second
+	defaultStatsdReporterFlushBytes    = 1432
+)
+
+var RootScope Scope
+var once sync.Once
+var started uint32
+
+// NewOpts create metrics options based config file
+func NewOpts() Opts {
+	opts := Opts{}
+	opts.Enabled = viper.GetBool("metrics.enabled")
+	if report := viper.GetString("metrics.reporter"); report != "" {
+		opts.Reporter = report
+	} else {
+		opts.Reporter = defaultReporterType
+	}
+	if interval := viper.GetDuration("metrics.interval"); interval > 0 {
+		opts.Interval = interval
+	} else {
+		opts.Interval = defaultInterval
+	}
+
+	if opts.Reporter == statsdReporterType {
+		statsdOpts := StatsdReporterOpts{}
+		statsdOpts.Address = viper.GetString("metrics.statsdReporter.address")
+		if flushInterval := viper.GetDuration("metrics.statsdReporter.flushInterval"); flushInterval > 0 {
+			statsdOpts.FlushInterval = flushInterval
+		} else {
+			statsdOpts.FlushInterval = defaultStatsdReporterFlushInterval
+		}
+		if flushBytes := viper.GetInt("metrics.statsdReporter.flushBytes"); flushBytes > 0 {
+			statsdOpts.FlushBytes = flushBytes
+		} else {
+			statsdOpts.FlushBytes = defaultStatsdReporterFlushBytes
+		}
+		opts.StatsdReporterOpts = statsdOpts
+	}
+
+	if opts.Reporter == promReporterType {
+		promOpts := PromReporterOpts{}
+		promOpts.ListenAddress = viper.GetString("metrics.promReporter.listenAddress")
+		opts.PromReporterOpts = promOpts
+	}
+
+	return opts
+}
+
+//Init initializes global root metrics scope instance, all callers can only use it to extend sub scope
+func Init(opts Opts) (err error) {
+	once.Do(func() {
+		RootScope, err = create(opts)
+	})
+
+	return
+}
+
+//Start starts metrics server
+func Start() error {
+	if atomic.CompareAndSwapUint32(&started, 0, 1) {
+		return RootScope.Start()
+	}
+	return nil
+}
+
+//Shutdown closes underlying resources used by metrics server
+func Shutdown() error {
+	if atomic.CompareAndSwapUint32(&started, 1, 0) {
+		err := RootScope.Close()
+		RootScope = nil
+		return err
+	}
+
+	return nil
+}
+
+type StatsdReporterOpts struct {
+	Address       string
+	FlushInterval time.Duration
+	FlushBytes    int
+}
+
+type PromReporterOpts struct {
+	ListenAddress string
+}
+
+type Opts struct {
+	Reporter           string
+	Interval           time.Duration
+	Enabled            bool
+	StatsdReporterOpts StatsdReporterOpts
+	PromReporterOpts   PromReporterOpts
+}
+
+type noOpCounter struct {
+}
+
+func (c *noOpCounter) Inc(v int64) {
+
+}
+
+type noOpGauge struct {
+}
+
+func (g *noOpGauge) Update(v float64) {
+
+}
+
+type noOpScope struct {
+	counter *noOpCounter
+	gauge   *noOpGauge
+}
+
+func (s *noOpScope) Counter(name string) Counter {
+	return s.counter
+}
+
+func (s *noOpScope) Gauge(name string) Gauge {
+	return s.gauge
+}
+
+func (s *noOpScope) Tagged(tags map[string]string) Scope {
+	return s
+}
+
+func (s *noOpScope) SubScope(prefix string) Scope {
+	return s
+}
+
+func (s *noOpScope) Close() error {
+	return nil
+}
+
+func (s *noOpScope) Start() error {
+	return nil
+}
+
+func newNoOpScope() Scope {
+	return &noOpScope{
+		counter: &noOpCounter{},
+		gauge:   &noOpGauge{},
+	}
+}
+
+func create(opts Opts) (rootScope Scope, e error) {
+	if !opts.Enabled {
+		rootScope = newNoOpScope()
+		return
+	} else {
+		if opts.Interval <= 0 {
+			e = fmt.Errorf("invalid Interval option %d", opts.Interval)
+			return
+		}
+
+		if opts.Reporter != statsdReporterType && opts.Reporter != promReporterType {
+			e = fmt.Errorf("not supported Reporter type %s", opts.Reporter)
+			return
+		}
+
+		var reporter tally.StatsReporter
+		var cachedReporter tally.CachedStatsReporter
+		if opts.Reporter == statsdReporterType {
+			reporter, e = newStatsdReporter(opts.StatsdReporterOpts)
+		}
+
+		if opts.Reporter == promReporterType {
+			cachedReporter, e = newPromReporter(opts.PromReporterOpts)
+		}
+
+		if e != nil {
+			return
+		}
+
+		rootScope = newRootScope(
+			tally.ScopeOptions{
+				Prefix:         namespace,
+				Reporter:       reporter,
+				CachedReporter: cachedReporter,
+			}, opts.Interval)
+		return
+	}
+}