traefik/pkg/server/service/loadbalancer/wrr/wrr_test.go

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package wrr
import (
"context"
"net/http"
"net/http/httptest"
"testing"
"github.com/stretchr/testify/assert"
"github.com/traefik/traefik/v2/pkg/config/dynamic"
)
func Int(v int) *int { return &v }
type responseRecorder struct {
*httptest.ResponseRecorder
save map[string]int
sequence []string
status []int
}
func (r *responseRecorder) WriteHeader(statusCode int) {
r.save[r.Header().Get("server")]++
r.sequence = append(r.sequence, r.Header().Get("server"))
r.status = append(r.status, statusCode)
r.ResponseRecorder.WriteHeader(statusCode)
}
func TestBalancer(t *testing.T) {
balancer := New(nil, nil)
balancer.AddService("first", http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
rw.Header().Set("server", "first")
rw.WriteHeader(http.StatusOK)
}), Int(3))
balancer.AddService("second", http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
rw.Header().Set("server", "second")
rw.WriteHeader(http.StatusOK)
}), Int(1))
recorder := &responseRecorder{ResponseRecorder: httptest.NewRecorder(), save: map[string]int{}}
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for range 4 {
balancer.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/", nil))
}
assert.Equal(t, 3, recorder.save["first"])
assert.Equal(t, 1, recorder.save["second"])
}
func TestBalancerNoService(t *testing.T) {
balancer := New(nil, nil)
recorder := httptest.NewRecorder()
balancer.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/", nil))
assert.Equal(t, http.StatusInternalServerError, recorder.Result().StatusCode)
}
func TestBalancerOneServerZeroWeight(t *testing.T) {
balancer := New(nil, nil)
balancer.AddService("first", http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
rw.Header().Set("server", "first")
rw.WriteHeader(http.StatusOK)
}), Int(1))
balancer.AddService("second", http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {}), Int(0))
recorder := &responseRecorder{ResponseRecorder: httptest.NewRecorder(), save: map[string]int{}}
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for range 3 {
balancer.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/", nil))
}
assert.Equal(t, 3, recorder.save["first"])
}
type key string
const serviceName key = "serviceName"
func TestBalancerNoServiceUp(t *testing.T) {
balancer := New(nil, nil)
balancer.AddService("first", http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
rw.WriteHeader(http.StatusInternalServerError)
}), Int(1))
balancer.AddService("second", http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
rw.WriteHeader(http.StatusInternalServerError)
}), Int(1))
balancer.SetStatus(context.WithValue(context.Background(), serviceName, "parent"), "first", false)
balancer.SetStatus(context.WithValue(context.Background(), serviceName, "parent"), "second", false)
recorder := httptest.NewRecorder()
balancer.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/", nil))
assert.Equal(t, http.StatusServiceUnavailable, recorder.Result().StatusCode)
}
func TestBalancerOneServerDown(t *testing.T) {
balancer := New(nil, nil)
balancer.AddService("first", http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
rw.Header().Set("server", "first")
rw.WriteHeader(http.StatusOK)
}), Int(1))
balancer.AddService("second", http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
rw.WriteHeader(http.StatusInternalServerError)
}), Int(1))
balancer.SetStatus(context.WithValue(context.Background(), serviceName, "parent"), "second", false)
recorder := &responseRecorder{ResponseRecorder: httptest.NewRecorder(), save: map[string]int{}}
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for range 3 {
balancer.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/", nil))
}
assert.Equal(t, 3, recorder.save["first"])
}
func TestBalancerDownThenUp(t *testing.T) {
balancer := New(nil, nil)
balancer.AddService("first", http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
rw.Header().Set("server", "first")
rw.WriteHeader(http.StatusOK)
}), Int(1))
balancer.AddService("second", http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
rw.Header().Set("server", "second")
rw.WriteHeader(http.StatusOK)
}), Int(1))
balancer.SetStatus(context.WithValue(context.Background(), serviceName, "parent"), "second", false)
recorder := &responseRecorder{ResponseRecorder: httptest.NewRecorder(), save: map[string]int{}}
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for range 3 {
balancer.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/", nil))
}
assert.Equal(t, 3, recorder.save["first"])
balancer.SetStatus(context.WithValue(context.Background(), serviceName, "parent"), "second", true)
recorder = &responseRecorder{ResponseRecorder: httptest.NewRecorder(), save: map[string]int{}}
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for range 2 {
balancer.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/", nil))
}
assert.Equal(t, 1, recorder.save["first"])
assert.Equal(t, 1, recorder.save["second"])
}
func TestBalancerPropagate(t *testing.T) {
balancer1 := New(nil, &dynamic.HealthCheck{})
balancer1.AddService("first", http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
rw.Header().Set("server", "first")
rw.WriteHeader(http.StatusOK)
}), Int(1))
balancer1.AddService("second", http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
rw.Header().Set("server", "second")
rw.WriteHeader(http.StatusOK)
}), Int(1))
balancer2 := New(nil, &dynamic.HealthCheck{})
balancer2.AddService("third", http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
rw.Header().Set("server", "third")
rw.WriteHeader(http.StatusOK)
}), Int(1))
balancer2.AddService("fourth", http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
rw.Header().Set("server", "fourth")
rw.WriteHeader(http.StatusOK)
}), Int(1))
topBalancer := New(nil, &dynamic.HealthCheck{})
topBalancer.AddService("balancer1", balancer1, Int(1))
_ = balancer1.RegisterStatusUpdater(func(up bool) {
topBalancer.SetStatus(context.WithValue(context.Background(), serviceName, "top"), "balancer1", up)
// TODO(mpl): if test gets flaky, add channel or something here to signal that
// propagation is done, and wait on it before sending request.
})
topBalancer.AddService("balancer2", balancer2, Int(1))
_ = balancer2.RegisterStatusUpdater(func(up bool) {
topBalancer.SetStatus(context.WithValue(context.Background(), serviceName, "top"), "balancer2", up)
})
recorder := &responseRecorder{ResponseRecorder: httptest.NewRecorder(), save: map[string]int{}}
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for range 8 {
topBalancer.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/", nil))
}
assert.Equal(t, 2, recorder.save["first"])
assert.Equal(t, 2, recorder.save["second"])
assert.Equal(t, 2, recorder.save["third"])
assert.Equal(t, 2, recorder.save["fourth"])
wantStatus := []int{200, 200, 200, 200, 200, 200, 200, 200}
assert.Equal(t, wantStatus, recorder.status)
// fourth gets downed, but balancer2 still up since third is still up.
balancer2.SetStatus(context.WithValue(context.Background(), serviceName, "top"), "fourth", false)
recorder = &responseRecorder{ResponseRecorder: httptest.NewRecorder(), save: map[string]int{}}
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for range 8 {
topBalancer.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/", nil))
}
assert.Equal(t, 2, recorder.save["first"])
assert.Equal(t, 2, recorder.save["second"])
assert.Equal(t, 4, recorder.save["third"])
assert.Equal(t, 0, recorder.save["fourth"])
wantStatus = []int{200, 200, 200, 200, 200, 200, 200, 200}
assert.Equal(t, wantStatus, recorder.status)
// third gets downed, and the propagation triggers balancer2 to be marked as
// down as well for topBalancer.
balancer2.SetStatus(context.WithValue(context.Background(), serviceName, "top"), "third", false)
recorder = &responseRecorder{ResponseRecorder: httptest.NewRecorder(), save: map[string]int{}}
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for range 8 {
topBalancer.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/", nil))
}
assert.Equal(t, 4, recorder.save["first"])
assert.Equal(t, 4, recorder.save["second"])
assert.Equal(t, 0, recorder.save["third"])
assert.Equal(t, 0, recorder.save["fourth"])
wantStatus = []int{200, 200, 200, 200, 200, 200, 200, 200}
assert.Equal(t, wantStatus, recorder.status)
}
func TestBalancerAllServersZeroWeight(t *testing.T) {
balancer := New(nil, nil)
balancer.AddService("test", http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {}), Int(0))
balancer.AddService("test2", http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {}), Int(0))
recorder := httptest.NewRecorder()
balancer.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/", nil))
assert.Equal(t, http.StatusInternalServerError, recorder.Result().StatusCode)
}
func TestSticky(t *testing.T) {
balancer := New(&dynamic.Sticky{
Cookie: &dynamic.Cookie{Name: "test"},
}, nil)
balancer.AddService("first", http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
rw.Header().Set("server", "first")
rw.WriteHeader(http.StatusOK)
}), Int(1))
balancer.AddService("second", http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
rw.Header().Set("server", "second")
rw.WriteHeader(http.StatusOK)
}), Int(2))
recorder := &responseRecorder{ResponseRecorder: httptest.NewRecorder(), save: map[string]int{}}
req := httptest.NewRequest(http.MethodGet, "/", nil)
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for range 3 {
for _, cookie := range recorder.Result().Cookies() {
assert.NotContains(t, "test=first", cookie.Value)
assert.NotContains(t, "test=second", cookie.Value)
req.AddCookie(cookie)
}
recorder.ResponseRecorder = httptest.NewRecorder()
balancer.ServeHTTP(recorder, req)
}
assert.Equal(t, 0, recorder.save["first"])
assert.Equal(t, 3, recorder.save["second"])
}
func TestSticky_FallBack(t *testing.T) {
balancer := New(&dynamic.Sticky{
Cookie: &dynamic.Cookie{Name: "test"},
}, nil)
balancer.AddService("first", http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
rw.Header().Set("server", "first")
rw.WriteHeader(http.StatusOK)
}), Int(1))
balancer.AddService("second", http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
rw.Header().Set("server", "second")
rw.WriteHeader(http.StatusOK)
}), Int(2))
recorder := &responseRecorder{ResponseRecorder: httptest.NewRecorder(), save: map[string]int{}}
req := httptest.NewRequest(http.MethodGet, "/", nil)
req.AddCookie(&http.Cookie{Name: "test", Value: "second"})
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for range 3 {
recorder.ResponseRecorder = httptest.NewRecorder()
balancer.ServeHTTP(recorder, req)
}
assert.Equal(t, 0, recorder.save["first"])
assert.Equal(t, 3, recorder.save["second"])
}
// TestBalancerBias makes sure that the WRR algorithm spreads elements evenly right from the start,
// and that it does not "over-favor" the high-weighted ones with a biased start-up regime.
func TestBalancerBias(t *testing.T) {
balancer := New(nil, nil)
balancer.AddService("first", http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
rw.Header().Set("server", "A")
rw.WriteHeader(http.StatusOK)
}), Int(11))
balancer.AddService("second", http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
rw.Header().Set("server", "B")
rw.WriteHeader(http.StatusOK)
}), Int(3))
recorder := &responseRecorder{ResponseRecorder: httptest.NewRecorder(), save: map[string]int{}}
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for range 14 {
balancer.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/", nil))
}
wantSequence := []string{"A", "A", "A", "B", "A", "A", "A", "A", "B", "A", "A", "A", "B", "A"}
assert.Equal(t, wantSequence, recorder.sequence)
}