package pacer
import (
"errors"
"sync"
"testing"
"time"
"github.com/stretchr/testify/assert"
)
func TestNew(t *testing.T) {
const expectedRetries = 7
const expectedConnections = 9
p := New(RetriesOption(expectedRetries), MaxConnectionsOption(expectedConnections))
if d, ok := p.calculator.(*Default); ok {
assert.Equal(t, 10*time.Millisecond, d.minSleep)
assert.Equal(t, 2*time.Second, d.maxSleep)
assert.Equal(t, d.minSleep, p.state.SleepTime)
assert.Equal(t, uint(2), d.decayConstant)
assert.Equal(t, uint(1), d.attackConstant)
} else {
t.Errorf("calculator")
}
assert.Equal(t, expectedRetries, p.retries)
assert.Equal(t, 1, cap(p.pacer))
assert.Equal(t, 1, len(p.pacer))
assert.Equal(t, expectedConnections, p.maxConnections)
assert.Equal(t, expectedConnections, cap(p.connTokens))
assert.Equal(t, 0, p.state.ConsecutiveRetries)
}
func TestMaxConnections(t *testing.T) {
p := New()
p.SetMaxConnections(20)
assert.Equal(t, 20, p.maxConnections)
assert.Equal(t, 20, cap(p.connTokens))
p.SetMaxConnections(0)
assert.Equal(t, 0, p.maxConnections)
assert.Nil(t, p.connTokens)
}
func TestDecay(t *testing.T) {
c := NewDefault(MinSleep(1*time.Microsecond), MaxSleep(1*time.Second))
for _, test := range []struct {
in State
attackConstant uint
want time.Duration
}{
{State{SleepTime: 8 * time.Millisecond}, 1, 4 * time.Millisecond},
{State{SleepTime: 1 * time.Millisecond}, 0, 1 * time.Microsecond},
{State{SleepTime: 1 * time.Millisecond}, 2, (3 * time.Millisecond) / 4},
{State{SleepTime: 1 * time.Millisecond}, 3, (7 * time.Millisecond) / 8},
} {
c.decayConstant = test.attackConstant
got := c.Calculate(test.in)
assert.Equal(t, test.want, got, "test: %+v", test)
}
}
func TestAttack(t *testing.T) {
c := NewDefault(MinSleep(1*time.Microsecond), MaxSleep(1*time.Second))
for _, test := range []struct {
in State
attackConstant uint
want time.Duration
}{
{State{SleepTime: 1 * time.Millisecond, ConsecutiveRetries: 1}, 1, 2 * time.Millisecond},
{State{SleepTime: 1 * time.Millisecond, ConsecutiveRetries: 1}, 0, 1 * time.Second},
{State{SleepTime: 1 * time.Millisecond, ConsecutiveRetries: 1}, 2, (4 * time.Millisecond) / 3},
{State{SleepTime: 1 * time.Millisecond, ConsecutiveRetries: 1}, 3, (8 * time.Millisecond) / 7},
} {
c.attackConstant = test.attackConstant
got := c.Calculate(test.in)
assert.Equal(t, test.want, got, "test: %+v", test)
}
}
func TestSetRetries(t *testing.T) {
p := New()
p.SetRetries(18)
assert.Equal(t, 18, p.retries)
}
// emptyTokens empties the pacer of all its tokens
func emptyTokens(p *Pacer) {
for len(p.pacer) != 0 {
<-p.pacer
}
for len(p.connTokens) != 0 {
<-p.connTokens
}
}
// waitForPace waits for duration for the pace to arrive
// returns the time that it arrived or a zero time
func waitForPace(p *Pacer, duration time.Duration) (when time.Time) {
select {
case <-time.After(duration):
return
case <-p.pacer:
return time.Now()
}
}
func TestBeginCall(t *testing.T) {
p := New(MaxConnectionsOption(10), CalculatorOption(NewDefault(MinSleep(1*time.Millisecond))))
emptyTokens(p)
go p.beginCall()
if !waitForPace(p, 10*time.Millisecond).IsZero() {
t.Errorf("beginSleep fired too early #1")
}
startTime := time.Now()
p.pacer <- struct{}{}
time.Sleep(1 * time.Millisecond)
connTime := time.Now()
p.connTokens <- struct{}{}
time.Sleep(1 * time.Millisecond)
paceTime := waitForPace(p, 1000*time.Millisecond)
if paceTime.IsZero() {
t.Errorf("beginSleep didn't fire")
} else if paceTime.Sub(startTime) < 0 {
t.Errorf("pace arrived before returning pace token")
} else if paceTime.Sub(connTime) < 0 {
t.Errorf("pace arrived before sending conn token")
}
}
func TestBeginCallZeroConnections(t *testing.T) {
p := New(MaxConnectionsOption(0), CalculatorOption(NewDefault(MinSleep(1*time.Millisecond))))
emptyTokens(p)
go p.beginCall()
if !waitForPace(p, 10*time.Millisecond).IsZero() {
t.Errorf("beginSleep fired too early #1")
}
startTime := time.Now()
p.pacer <- struct{}{}
time.Sleep(1 * time.Millisecond)
paceTime := waitForPace(p, 1000*time.Millisecond)
if paceTime.IsZero() {
t.Errorf("beginSleep didn't fire")
} else if paceTime.Sub(startTime) < 0 {
t.Errorf("pace arrived before returning pace token")
}
}
func TestDefaultPacer(t *testing.T) {
c := NewDefault(MinSleep(1*time.Millisecond), MaxSleep(1*time.Second), DecayConstant(2))
for _, test := range []struct {
state State
want time.Duration
}{
{State{SleepTime: 1 * time.Millisecond, ConsecutiveRetries: 1}, 2 * time.Millisecond},
{State{SleepTime: 1 * time.Second, ConsecutiveRetries: 1}, 1 * time.Second},
{State{SleepTime: (3 * time.Second) / 4, ConsecutiveRetries: 1}, 1 * time.Second},
{State{SleepTime: 1 * time.Second}, 750 * time.Millisecond},
{State{SleepTime: 1000 * time.Microsecond}, 1 * time.Millisecond},
{State{SleepTime: 1200 * time.Microsecond}, 1 * time.Millisecond},
} {
got := c.Calculate(test.state)
assert.Equal(t, test.want, got, "test: %+v", test)
}
}
func TestAzureIMDSPacer(t *testing.T) {
c := NewAzureIMDS()
for _, test := range []struct {
state State
want time.Duration
}{
{State{SleepTime: 0, ConsecutiveRetries: 0}, 0},
{State{SleepTime: 0, ConsecutiveRetries: 1}, 2 * time.Second},
{State{SleepTime: 2 * time.Second, ConsecutiveRetries: 2}, 6 * time.Second},
{State{SleepTime: 6 * time.Second, ConsecutiveRetries: 3}, 14 * time.Second},
{State{SleepTime: 14 * time.Second, ConsecutiveRetries: 4}, 30 * time.Second},
} {
got := c.Calculate(test.state)
assert.Equal(t, test.want, got, "test: %+v", test)
}
}
func TestGoogleDrivePacer(t *testing.T) {
// Do lots of times because of the random number!
for _, test := range []struct {
state State
want time.Duration
}{
{State{SleepTime: 1 * time.Millisecond}, 0},
{State{SleepTime: 10 * time.Millisecond}, 0},
{State{SleepTime: 1 * time.Second, ConsecutiveRetries: 1}, 1*time.Second + 500*time.Millisecond},
{State{SleepTime: 1 * time.Second, ConsecutiveRetries: 2}, 2*time.Second + 500*time.Millisecond},
{State{SleepTime: 1 * time.Second, ConsecutiveRetries: 3}, 4*time.Second + 500*time.Millisecond},
{State{SleepTime: 1 * time.Second, ConsecutiveRetries: 4}, 8*time.Second + 500*time.Millisecond},
{State{SleepTime: 1 * time.Second, ConsecutiveRetries: 5}, 16*time.Second + 500*time.Millisecond},
{State{SleepTime: 1 * time.Second, ConsecutiveRetries: 6}, 16*time.Second + 500*time.Millisecond},
{State{SleepTime: 1 * time.Second, ConsecutiveRetries: 7}, 16*time.Second + 500*time.Millisecond},
} {
const n = 1000
var sum time.Duration
// measure average time over n cycles
for i := 0; i < n; i++ {
c := NewGoogleDrive(MinSleep(1 * time.Millisecond))
sum += c.Calculate(test.state)
}
got := sum / n
assert.False(t, got < (test.want*9)/10 || got > (test.want*11)/10, "test: %+v, got: %v", test, got)
}
const minSleep = 2 * time.Millisecond
for _, test := range []struct {
calls int
want int
}{
{1, 0},
{9, 0},
{10, 0},
{11, 1},
{12, 2},
} {
c := NewGoogleDrive(MinSleep(minSleep), Burst(10))
count := 0
for i := 0; i < test.calls; i++ {
sleep := c.Calculate(State{})
if sleep != 0 {
count++
}
}
assert.Equalf(t, test.want, count, "test: %+v, got: %v", test, count)
}
}
func TestS3Pacer(t *testing.T) {
c := NewS3(MinSleep(10*time.Millisecond), MaxSleep(1*time.Second), DecayConstant(2))
for _, test := range []struct {
state State
want time.Duration
}{
{State{SleepTime: 0, ConsecutiveRetries: 1}, 10 * time.Millisecond}, //Things were going ok, we failed once, back off to minSleep
{State{SleepTime: 10 * time.Millisecond, ConsecutiveRetries: 1}, 20 * time.Millisecond}, //Another fail, double the backoff
{State{SleepTime: 10 * time.Millisecond}, 0}, //Things start going ok when we're at minSleep; should result in no sleep
{State{SleepTime: 12 * time.Millisecond}, 0}, //*near* minsleep and going ok, decay would take below minSleep, should go to 0
{State{SleepTime: 0}, 0}, //Things have been going ok; not retrying should keep sleep at 0
{State{SleepTime: 1 * time.Second, ConsecutiveRetries: 1}, 1 * time.Second}, //Check maxSleep is enforced
{State{SleepTime: (3 * time.Second) / 4, ConsecutiveRetries: 1}, 1 * time.Second}, //Check attack heading to maxSleep doesn't exceed maxSleep
{State{SleepTime: 1 * time.Second}, 750 * time.Millisecond}, //Check decay from maxSleep
{State{SleepTime: 48 * time.Millisecond}, 36 * time.Millisecond}, //Check simple decay above minSleep
} {
got := c.Calculate(test.state)
assert.Equal(t, test.want, got, "test: %+v", test)
}
}
func TestEndCall(t *testing.T) {
p := New(MaxConnectionsOption(5))
emptyTokens(p)
p.state.ConsecutiveRetries = 1
p.endCall(true, nil)
assert.Equal(t, 1, len(p.connTokens))
assert.Equal(t, 2, p.state.ConsecutiveRetries)
}
func TestEndCallZeroConnections(t *testing.T) {
p := New(MaxConnectionsOption(0))
emptyTokens(p)
p.state.ConsecutiveRetries = 1
p.endCall(false, nil)
assert.Equal(t, 0, len(p.connTokens))
assert.Equal(t, 0, p.state.ConsecutiveRetries)
}
var errFoo = errors.New("foo")
type dummyPaced struct {
retry bool
called int
wait *sync.Cond
}
func (dp *dummyPaced) fn() (bool, error) {
if dp.wait != nil {
dp.wait.L.Lock()
dp.called++
dp.wait.Wait()
dp.wait.L.Unlock()
} else {
dp.called++
}
return dp.retry, errFoo
}
func TestCallFixed(t *testing.T) {
p := New(CalculatorOption(NewDefault(MinSleep(1*time.Millisecond), MaxSleep(2*time.Millisecond))))
dp := &dummyPaced{retry: false}
err := p.call(dp.fn, 10)
assert.Equal(t, 1, dp.called)
assert.Equal(t, errFoo, err)
}
func Test_callRetry(t *testing.T) {
p := New(CalculatorOption(NewDefault(MinSleep(1*time.Millisecond), MaxSleep(2*time.Millisecond))))
dp := &dummyPaced{retry: true}
err := p.call(dp.fn, 10)
assert.Equal(t, 10, dp.called)
assert.Equal(t, errFoo, err)
}
func TestCall(t *testing.T) {
p := New(RetriesOption(20), CalculatorOption(NewDefault(MinSleep(1*time.Millisecond), MaxSleep(2*time.Millisecond))))
dp := &dummyPaced{retry: true}
err := p.Call(dp.fn)
assert.Equal(t, 20, dp.called)
assert.Equal(t, errFoo, err)
}
func TestCallParallel(t *testing.T) {
p := New(MaxConnectionsOption(3), RetriesOption(1), CalculatorOption(NewDefault(MinSleep(100*time.Microsecond), MaxSleep(1*time.Millisecond))))
wait := sync.NewCond(&sync.Mutex{})
funcs := make([]*dummyPaced, 5)
for i := range funcs {
dp := &dummyPaced{wait: wait}
funcs[i] = dp
go func() {
assert.Equal(t, errFoo, p.CallNoRetry(dp.fn))
}()
}
time.Sleep(250 * time.Millisecond)
called := 0
wait.L.Lock()
for _, dp := range funcs {
called += dp.called
}
wait.L.Unlock()
assert.Equal(t, 3, called)
wait.Broadcast()
time.Sleep(250 * time.Millisecond)
called = 0
wait.L.Lock()
for _, dp := range funcs {
called += dp.called
}
wait.L.Unlock()
assert.Equal(t, 5, called)
wait.Broadcast()
}