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package instance
import (
"context"
"fmt"
"io"
"reflect"
"testing"
"time"
"github.com/go-kit/kit/endpoint"
"github.com/go-kit/kit/sd"
"github.com/go-kit/log"
)
var _ sd.Instancer = (*Cache)(nil) // API check
// The test verifies the following:
// registering causes initial notification of the current state
// instances are sorted
// different update causes new notification
// identical notifications cause no updates
// no updates after de-registering
func TestCache(t *testing.T) {
e1 := sd.Event{Instances: []string{"y", "x"}} // not sorted
e2 := sd.Event{Instances: []string{"c", "a", "b"}}
cache := NewCache()
if want, have := 0, len(cache.State().Instances); want != have {
t.Fatalf("want %v instances, have %v", want, have)
}
cache.Update(e1) // sets initial state
if want, have := 2, len(cache.State().Instances); want != have {
t.Fatalf("want %v instances, have %v", want, have)
}
r1 := make(chan sd.Event)
go cache.Register(r1)
expectUpdate(t, r1, []string{"x", "y"})
go cache.Update(e2) // different set
expectUpdate(t, r1, []string{"a", "b", "c"})
cache.Deregister(r1)
close(r1)
}
func expectUpdate(t *testing.T, r chan sd.Event, expect []string) {
select {
case e := <-r:
if want, have := expect, e.Instances; !reflect.DeepEqual(want, have) {
t.Fatalf("want: %v, have: %v", want, have)
}
case <-time.After(time.Second):
t.Fatalf("did not receive expected update %v", expect)
}
}
func TestRegistry(t *testing.T) {
reg := make(registry)
c1 := make(chan sd.Event, 1)
c2 := make(chan sd.Event, 1)
reg.register(c1)
reg.register(c2)
// validate that both channels receive the update
reg.broadcast(sd.Event{Instances: []string{"x", "y"}})
if want, have := []string{"x", "y"}, (<-c1).Instances; !reflect.DeepEqual(want, have) {
t.Fatalf("want: %v, have: %v", want, have)
}
if want, have := []string{"x", "y"}, (<-c2).Instances; !reflect.DeepEqual(want, have) {
t.Fatalf("want: %v, have: %v", want, have)
}
reg.deregister(c1)
reg.deregister(c2)
close(c1)
close(c2)
// if deregister didn't work, broadcast would panic on closed channels
reg.broadcast(sd.Event{Instances: []string{"x", "y"}})
}
// This test is meant to be run with the race detector enabled: -race.
// It ensures that every registered observer receives a copy
// of sd.Event.Instances because observers can directly modify the field.
// For example, endpointCache calls sort.Strings() on sd.Event.Instances.
func TestDataRace(t *testing.T) {
instances := make([]string, 0)
// the number of iterations here maters because we need sort.Strings to
// perform a Swap in doPivot -> medianOfThree to cause a data race.
for i := 1; i < 1000; i++ {
instances = append(instances, fmt.Sprintf("%v", i))
}
e1 := sd.Event{Instances: instances}
cache := NewCache()
cache.Update(e1)
nullEndpoint := func(_ context.Context, _ interface{}) (interface{}, error) {
return nil, nil
}
nullFactory := func(instance string) (endpoint.Endpoint, io.Closer, error) {
return nullEndpoint, nil, nil
}
logger := log.Logger(log.LoggerFunc(func(keyvals ...interface{}) error {
return nil
}))
sd.NewEndpointer(cache, nullFactory, logger)
sd.NewEndpointer(cache, nullFactory, logger)
}
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