put GCNotify behind an inerface

gc.go

@@ -0,0 +1,38 @@
+// Copyright 2017 Pilosa Corp.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package pilosa
+
+// GCNotifier represents an interface for garbage collection notificationss.
+type GCNotifier interface {
+	Close()
+	AfterGC() <-chan struct{}
+}
+
+func init() {
+	NopGCNotifier = &nopGCNotifier{}
+}
+
+// NopGCNotifier represents a GCNotifier that doesn't do anything.
+var NopGCNotifier GCNotifier
+
+type nopGCNotifier struct{}
+
+// Close is a no-op implemenetation of GCNotifier Close method.
+func (n *nopGCNotifier) Close() {}
+
+// AfterGC is a no-op implemenetation of GCNotifier AfterGC method.
+func (c *nopGCNotifier) AfterGC() <-chan struct{} {
+	return nil
+}

gcnotify/gcnotify.go

@@ -0,0 +1,44 @@
+// Copyright 2017 Pilosa Corp.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package gcnotify
+
+import (
+	"github.com/CAFxX/gcnotifier"
+	"github.com/pilosa/pilosa"
+)
+
+// Ensure ActiveGCNotifier implements interface.
+var _ pilosa.GCNotifier = &ActiveGCNotifier{}
+
+type ActiveGCNotifier struct {
+	gcn *gcnotifier.GCNotifier
+}
+
+// NewActiveGCNotifier creates an active GCNotifier.
+func NewActiveGCNotifier() *ActiveGCNotifier {
+	return &ActiveGCNotifier{
+		gcn: gcnotifier.New(),
+	}
+}
+
+// Close implements the GCNotifier interface.
+func (n *ActiveGCNotifier) Close() {
+	n.gcn.Close()
+}
+
+// AfterGC implements the GCNotifier interface.
+func (n *ActiveGCNotifier) AfterGC() <-chan struct{} {
+	return n.gcn.AfterGC()
+}

server.go

@@ -31,7 +31,6 @@ import (
 	"sync"
 	"time"
 
-	"github.com/CAFxX/gcnotifier"
 	"github.com/gogo/protobuf/proto"
 	"github.com/pilosa/pilosa/diagnostics"
 	"github.com/pilosa/pilosa/internal"
@@ -73,6 +72,8 @@ type Server struct {
 	Cluster     *Cluster
 	diagnostics *diagnostics.Diagnostics
 
+	GCNotifier GCNotifier
+
 	// Background monitoring intervals.
 	AntiEntropyInterval time.Duration
 	MetricInterval      time.Duration
@@ -103,6 +104,8 @@ func NewServer() *Server {
 
 		Network: "tcp",
 
+		GCNotifier: NopGCNotifier,
+
 		AntiEntropyInterval: DefaultAntiEntropyInterval,
 		MetricInterval:      0,
 		DiagnosticInterval:  0,
@@ -652,8 +655,7 @@ func (s *Server) monitorRuntime() {
 	ticker := time.NewTicker(s.MetricInterval)
 	defer ticker.Stop()
 
-	gcn := gcnotifier.New()
-	defer gcn.Close()
+	defer s.GCNotifier.Close()
 
 	s.Logger().Printf("runtime stats initializing (%s interval)", s.MetricInterval)
 
@@ -662,7 +664,7 @@ func (s *Server) monitorRuntime() {
 		select {
 		case <-s.closing:
 			return
-		case <-gcn.AfterGC():
+		case <-s.GCNotifier.AfterGC():
 			// GC just ran.
 			s.Holder.Stats.Count("garbage_collection", 1, 1.0)
 		case <-ticker.C:

server/server.go

@@ -33,6 +33,7 @@ import (
 	"crypto/tls"
 
 	"github.com/pilosa/pilosa"
+	"github.com/pilosa/pilosa/gcnotify"
 	"github.com/pilosa/pilosa/gossip"
 	"github.com/pilosa/pilosa/statsd"
 )
@@ -151,6 +152,7 @@ func (m *Command) SetupServer() error {
 	if m.Config.Metric.Diagnostics {
 		m.Server.DiagnosticInterval = time.Duration(DefaultDiagnosticsInterval)
 	}
+	m.Server.GCNotifier = gcnotify.NewActiveGCNotifier()
 	m.Server.Holder.Stats, err = NewStatsClient(m.Config.Metric.Service, m.Config.Metric.Host)
 	if err != nil {
 		return err