address comments

pkg/io/starter.go

@@ -0,0 +1,20 @@
+// Copyright (c) 2018 The Jaeger Authors.
+//
+// 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 io
+
+// Starter is the interface that wraps the basic Start() method.
+type Starter interface {
+	Start() error
+}

plugin/sampling/strategystore/adaptive/calculationstrategy/interface.go → plugin/sampling/internal/calculationstrategy/interface.go

@@ -19,10 +19,10 @@ type ProbabilityCalculator interface {
 	Calculate(targetQPS, curQPS, prevProbability float64) (newProbability float64)
 }
 
-// Func wraps a function of appropriate signature and makes a ProbabilityCalculator from it.
-type Func func(targetQPS, curQPS, prevProbability float64) (newProbability float64)
+// Calculate wraps a function of appropriate signature and makes a ProbabilityCalculator from it.
+type Calculate func(targetQPS, curQPS, prevProbability float64) (newProbability float64)
 
 // Calculate implements Calculator interface.
-func (f Func) Calculate(targetQPS, curQPS, prevProbability float64) float64 {
-	return f(targetQPS, curQPS, prevProbability)
+func (c Calculate) Calculate(targetQPS, curQPS, prevProbability float64) float64 {
+	return c(targetQPS, curQPS, prevProbability)
 }

plugin/sampling/strategystore/adaptive/calculationstrategy/interface_test.go → plugin/sampling/internal/calculationstrategy/interface_test.go

@@ -20,8 +20,8 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func TestFunc(t *testing.T) {
-	c := Func(func(targetQPS, qps, oldProbability float64) float64 {
+func TestCalculate(t *testing.T) {
+	c := Calculate(func(targetQPS, qps, oldProbability float64) float64 {
 		return targetQPS
 	})
 	val := 1.0

plugin/sampling/strategystore/adaptive/calculationstrategy/percentage_increase_capped_calculator_test.go → plugin/sampling/internal/calculationstrategy/percentage_increase_capped_calculator_test.go

@@ -20,7 +20,7 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func TestCalculate(t *testing.T) {
+func TestPercentageIncreaseCappedCalculator(t *testing.T) {
 	calculator := NewPercentageIncreaseCappedCalculator(0)
 	tests := []struct {
 		targetQPS           float64

plugin/sampling/strategystore/adaptive/internal/leader_election.go → plugin/sampling/internal/leaderelection/leader_election.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package internal
+package leaderelection
 
 import (
 	"sync"
@@ -31,7 +31,6 @@ var (
 // ElectionParticipant partakes in leader election to become leader.
 type ElectionParticipant interface {
 	IsLeader() bool
-	Start()
 }
 
 type electionParticipant struct {
@@ -54,17 +53,18 @@ type ElectionParticipantOptions struct {
 func NewElectionParticipant(lock dl.Lock, resourceName string, options ElectionParticipantOptions) ElectionParticipant {
 	return &electionParticipant{
 		ElectionParticipantOptions: options,
-		lock:         lock,
-		resourceName: resourceName,
-		isLeader:     atomic.NewBool(false),
-		closeChan:    make(chan struct{}),
+		lock:                       lock,
+		resourceName:               resourceName,
+		isLeader:                   atomic.NewBool(false),
+		closeChan:                  make(chan struct{}),
 	}
 }
 
 // Start runs a background thread which attempts to acquire the leader lock.
-func (p *electionParticipant) Start() {
+func (p *electionParticipant) Start() error {
 	p.wg.Add(1)
 	go p.runAcquireLockLoop()
+	return nil
 }
 
 // Close implements io.Closer.

plugin/sampling/strategystore/adaptive/internal/leader_election_test.go → plugin/sampling/internal/leaderelection/leader_election_test.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package internal
+package leaderelection
 
 import (
 	"errors"
@@ -26,6 +26,7 @@ import (
 	"go.uber.org/atomic"
 
 	lmocks "github.com/jaegertracing/jaeger/pkg/distributedlock/mocks"
+	jio "github.com/jaegertracing/jaeger/pkg/io"
 	"github.com/jaegertracing/jaeger/pkg/testutils"
 )
 
@@ -63,7 +64,7 @@ func TestAcquireLock(t *testing.T) {
 				ElectionParticipantOptions: ElectionParticipantOptions{
 					LeaderLeaseRefreshInterval:   leaderInterval,
 					FollowerLeaseRefreshInterval: followerInterval,
-					Logger: logger,
+					Logger:                       logger,
 				},
 				lock:         mockLock,
 				resourceName: "sampling_lock",
@@ -85,14 +86,14 @@ func TestRunAcquireLockLoop_followerOnly(t *testing.T) {
 	p := NewElectionParticipant(mockLock, "sampling_lock", ElectionParticipantOptions{
 		LeaderLeaseRefreshInterval:   time.Millisecond,
 		FollowerLeaseRefreshInterval: 5 * time.Millisecond,
-		Logger: logger,
+		Logger:                       logger,
 	},
 	)
 
 	defer func() {
 		assert.NoError(t, p.(io.Closer).Close())
 	}()
-	go p.Start()
+	go p.(jio.Starter).Start()
 
 	expectedErrorMsg := "Failed to acquire lock"
 	for i := 0; i < 1000; i++ {