func (s *RBSuite) TestRebalancerLive(c *C) {
a, b := testutils.NewResponder("a"), testutils.NewResponder("b")
defer a.Close()
defer b.Close()
fwd, err := forward.New()
c.Assert(err, IsNil)
lb, err := New(fwd)
c.Assert(err, IsNil)
rb, err := NewRebalancer(lb, RebalancerBackoff(time.Millisecond), RebalancerClock(s.clock))
c.Assert(err, IsNil)
rb.UpsertServer(testutils.ParseURI(a.URL))
rb.UpsertServer(testutils.ParseURI(b.URL))
rb.UpsertServer(testutils.ParseURI("http://localhost:62345"))
proxy := httptest.NewServer(rb)
defer proxy.Close()
for i := 0; i < 1000; i += 1 {
testutils.Get(proxy.URL)
if i%10 == 0 {
s.clock.CurrentTime = s.clock.CurrentTime.Add(rb.backoffDuration + time.Second)
}
}
// load balancer changed weights
c.Assert(rb.servers[0].curWeight, Equals, FSMMaxWeight)
c.Assert(rb.servers[1].curWeight, Equals, FSMMaxWeight)
c.Assert(rb.servers[2].curWeight, Equals, 1)
}
func (s *RBSuite) TestRebalancerRemoveServer(c *C) {
a, b := testutils.NewResponder("a"), testutils.NewResponder("b")
defer a.Close()
defer b.Close()
fwd, err := forward.New()
c.Assert(err, IsNil)
lb, err := New(fwd)
c.Assert(err, IsNil)
rb, err := NewRebalancer(lb)
c.Assert(err, IsNil)
rb.UpsertServer(testutils.ParseURI(a.URL))
rb.UpsertServer(testutils.ParseURI(b.URL))
proxy := httptest.NewServer(rb)
defer proxy.Close()
c.Assert(seq(c, proxy.URL, 3), DeepEquals, []string{"a", "b", "a"})
c.Assert(rb.RemoveServer(testutils.ParseURI(a.URL)), IsNil)
c.Assert(seq(c, proxy.URL, 3), DeepEquals, []string{"b", "b", "b"})
}
func (s *RRSuite) TestWeighted(c *C) {
a := testutils.NewResponder("a")
defer a.Close()
b := testutils.NewResponder("b")
defer b.Close()
fwd, err := forward.New()
c.Assert(err, IsNil)
lb, err := New(fwd)
c.Assert(err, IsNil)
lb.UpsertServer(testutils.ParseURI(a.URL), Weight(3))
lb.UpsertServer(testutils.ParseURI(b.URL), Weight(2))
proxy := httptest.NewServer(lb)
defer proxy.Close()
c.Assert(seq(c, proxy.URL, 6), DeepEquals, []string{"a", "a", "b", "a", "b", "a"})
w, ok := lb.ServerWeight(testutils.ParseURI(a.URL))
c.Assert(w, Equals, 3)
c.Assert(ok, Equals, true)
w, ok = lb.ServerWeight(testutils.ParseURI(b.URL))
c.Assert(w, Equals, 2)
c.Assert(ok, Equals, true)
w, ok = lb.ServerWeight(testutils.ParseURI("http://caramba:4000"))
c.Assert(w, Equals, -1)
c.Assert(ok, Equals, false)
}
func (s *RRSuite) TestUpsertWeight(c *C) {
a := testutils.NewResponder("a")
defer a.Close()
b := testutils.NewResponder("b")
defer b.Close()
fwd, err := forward.New()
c.Assert(err, IsNil)
lb, err := New(fwd)
c.Assert(err, IsNil)
c.Assert(lb.UpsertServer(testutils.ParseURI(a.URL)), IsNil)
c.Assert(lb.UpsertServer(testutils.ParseURI(b.URL)), IsNil)
proxy := httptest.NewServer(lb)
defer proxy.Close()
c.Assert(seq(c, proxy.URL, 3), DeepEquals, []string{"a", "b", "a"})
c.Assert(lb.UpsertServer(testutils.ParseURI(b.URL), Weight(3)), IsNil)
c.Assert(seq(c, proxy.URL, 4), DeepEquals, []string{"b", "b", "a", "b"})
}
// Test scenario when increaing the weight on good endpoints made it worse
func (s *RBSuite) TestRebalancerCascading(c *C) {
a, b, d := testutils.NewResponder("a"), testutils.NewResponder("b"), testutils.NewResponder("d")
defer a.Close()
defer b.Close()
defer d.Close()
fwd, err := forward.New()
c.Assert(err, IsNil)
lb, err := New(fwd)
c.Assert(err, IsNil)
newMeter := func() (Meter, error) {
return &testMeter{}, nil
}
rb, err := NewRebalancer(lb, RebalancerMeter(newMeter), RebalancerClock(s.clock), RebalancerLogger(s.log))
c.Assert(err, IsNil)
rb.UpsertServer(testutils.ParseURI(a.URL))
rb.UpsertServer(testutils.ParseURI(b.URL))
rb.UpsertServer(testutils.ParseURI(d.URL))
rb.servers[0].meter.(*testMeter).rating = 0.3
proxy := httptest.NewServer(rb)
defer proxy.Close()
for i := 0; i < 6; i += 1 {
testutils.Get(proxy.URL)
testutils.Get(proxy.URL)
s.clock.CurrentTime = s.clock.CurrentTime.Add(rb.backoffDuration + time.Second)
}
// We have increased the load, and the situation became worse as the other servers started failing
c.Assert(rb.servers[0].curWeight, Equals, 1)
c.Assert(rb.servers[1].curWeight, Equals, FSMMaxWeight)
c.Assert(rb.servers[2].curWeight, Equals, FSMMaxWeight)
// server a is now recovering, the weights should go back to the original state
rb.servers[0].meter.(*testMeter).rating = 0.3
rb.servers[1].meter.(*testMeter).rating = 0.2
rb.servers[2].meter.(*testMeter).rating = 0.2
for i := 0; i < 6; i += 1 {
testutils.Get(proxy.URL)
testutils.Get(proxy.URL)
s.clock.CurrentTime = s.clock.CurrentTime.Add(rb.backoffDuration + time.Second)
}
// the algo reverted it back
c.Assert(rb.servers[0].curWeight, Equals, 1)
c.Assert(rb.servers[1].curWeight, Equals, 1)
c.Assert(rb.servers[2].curWeight, Equals, 1)
}
// Test scenario when one server goes down after what it recovers
func (s *RBSuite) TestRebalancerRecovery(c *C) {
a, b := testutils.NewResponder("a"), testutils.NewResponder("b")
defer a.Close()
defer b.Close()
fwd, err := forward.New()
c.Assert(err, IsNil)
lb, err := New(fwd)
c.Assert(err, IsNil)
newMeter := func() (Meter, error) {
return &testMeter{}, nil
}
rb, err := NewRebalancer(lb, RebalancerMeter(newMeter), RebalancerClock(s.clock), RebalancerLogger(s.log))
c.Assert(err, IsNil)
rb.UpsertServer(testutils.ParseURI(a.URL))
rb.UpsertServer(testutils.ParseURI(b.URL))
rb.servers[0].meter.(*testMeter).rating = 0.3
proxy := httptest.NewServer(rb)
defer proxy.Close()
for i := 0; i < 6; i += 1 {
testutils.Get(proxy.URL)
testutils.Get(proxy.URL)
s.clock.CurrentTime = s.clock.CurrentTime.Add(rb.backoffDuration + time.Second)
}
c.Assert(rb.servers[0].curWeight, Equals, 1)
c.Assert(rb.servers[1].curWeight, Equals, FSMMaxWeight)
c.Assert(lb.servers[0].weight, Equals, 1)
c.Assert(lb.servers[1].weight, Equals, FSMMaxWeight)
// server a is now recovering, the weights should go back to the original state
rb.servers[0].meter.(*testMeter).rating = 0
for i := 0; i < 6; i += 1 {
testutils.Get(proxy.URL)
testutils.Get(proxy.URL)
s.clock.CurrentTime = s.clock.CurrentTime.Add(rb.backoffDuration + time.Second)
}
c.Assert(rb.servers[0].curWeight, Equals, 1)
c.Assert(rb.servers[1].curWeight, Equals, 1)
// Make sure we have applied the weights to the inner load balancer
c.Assert(lb.servers[0].weight, Equals, 1)
c.Assert(lb.servers[1].weight, Equals, 1)
}
// Removing the server resets the state
func (s *RBSuite) TestRebalancerReset(c *C) {
a, b, d := testutils.NewResponder("a"), testutils.NewResponder("b"), testutils.NewResponder("d")
defer a.Close()
defer b.Close()
defer d.Close()
fwd, err := forward.New()
c.Assert(err, IsNil)
lb, err := New(fwd)
c.Assert(err, IsNil)
newMeter := func() (Meter, error) {
return &testMeter{}, nil
}
rb, err := NewRebalancer(lb, RebalancerMeter(newMeter), RebalancerClock(s.clock), RebalancerLogger(s.log))
c.Assert(err, IsNil)
rb.UpsertServer(testutils.ParseURI(a.URL))
rb.UpsertServer(testutils.ParseURI(b.URL))
rb.UpsertServer(testutils.ParseURI(d.URL))
rb.servers[0].meter.(*testMeter).rating = 0.3
rb.servers[1].meter.(*testMeter).rating = 0
rb.servers[2].meter.(*testMeter).rating = 0
proxy := httptest.NewServer(rb)
defer proxy.Close()
for i := 0; i < 6; i += 1 {
testutils.Get(proxy.URL)
testutils.Get(proxy.URL)
s.clock.CurrentTime = s.clock.CurrentTime.Add(rb.backoffDuration + time.Second)
}
// load balancer changed weights
c.Assert(rb.servers[0].curWeight, Equals, 1)
c.Assert(rb.servers[1].curWeight, Equals, FSMMaxWeight)
c.Assert(rb.servers[2].curWeight, Equals, FSMMaxWeight)
// Removing servers has reset the state
rb.RemoveServer(testutils.ParseURI(d.URL))
c.Assert(rb.servers[0].curWeight, Equals, 1)
c.Assert(rb.servers[1].curWeight, Equals, 1)
}
func (s *RBSuite) TestRebalancerNormalOperation(c *C) {
a, b := testutils.NewResponder("a"), testutils.NewResponder("b")
defer a.Close()
defer b.Close()
fwd, err := forward.New()
c.Assert(err, IsNil)
lb, err := New(fwd)
c.Assert(err, IsNil)
rb, err := NewRebalancer(lb)
c.Assert(err, IsNil)
rb.UpsertServer(testutils.ParseURI(a.URL))
c.Assert(rb.Servers()[0].String(), Equals, a.URL)
proxy := httptest.NewServer(rb)
defer proxy.Close()
c.Assert(seq(c, proxy.URL, 3), DeepEquals, []string{"a", "a", "a"})
}