add canary-weight-total annotation (kubernetes#6338)

docs/user-guide/nginx-configuration/annotations.md

@@ -41,6 +41,7 @@ You can add these Kubernetes annotations to specific Ingress objects to customiz
 |[nginx.ingress.kubernetes.io/canary-by-header-pattern](#canary)|string|
 |[nginx.ingress.kubernetes.io/canary-by-cookie](#canary)|string|
 |[nginx.ingress.kubernetes.io/canary-weight](#canary)|number|
+|[nginx.ingress.kubernetes.io/canary-weight-total](#canary)|number|
 |[nginx.ingress.kubernetes.io/client-body-buffer-size](#client-body-buffer-size)|string|
 |[nginx.ingress.kubernetes.io/configuration-snippet](#configuration-snippet)|string|
 |[nginx.ingress.kubernetes.io/custom-http-errors](#custom-http-errors)|[]int|
@@ -138,7 +139,9 @@ In some cases, you may want to "canary" a new set of changes by sending a small
 
 * `nginx.ingress.kubernetes.io/canary-by-cookie`: The cookie to use for notifying the Ingress to route the request to the service specified in the Canary Ingress. When the cookie value is set to `always`, it will be routed to the canary. When the cookie is set to `never`, it will never be routed to the canary. For any other value, the cookie will be ignored and the request compared against the other canary rules by precedence.
 
-* `nginx.ingress.kubernetes.io/canary-weight`: The integer based (0 - 100) percent of random requests that should be routed to the service specified in the canary Ingress. A weight of 0 implies that no requests will be sent to the service in the Canary ingress by this canary rule. A weight of 100 means implies all requests will be sent to the alternative service specified in the Ingress.
+* `nginx.ingress.kubernetes.io/canary-weight`: The integer based (0 - <weight-total>) percent of random requests that should be routed to the service specified in the canary Ingress. A weight of 0 implies that no requests will be sent to the service in the Canary ingress by this canary rule. A weight of <weight-total> means implies all requests will be sent to the alternative service specified in the Ingress. `<weight-total>` defaults to 100, and can be increased via `nginx.ingress.kubernetes.io/canary-weight-total`.
+
+* `nginx.ingress.kubernetes.io/canary-weight-total`: The total weight of traffic. If unspecified, it defaults to 100.
 
 Canary rules are evaluated in order of precedence. Precedence is as follows:
 `canary-by-header -> canary-by-cookie -> canary-weight`

internal/ingress/annotations/canary/main.go

@@ -32,6 +32,7 @@ type canary struct {
 type Config struct {
 	Enabled       bool
 	Weight        int
+	WeightTotal   int
 	Header        string
 	HeaderValue   string
 	HeaderPattern string
@@ -59,6 +60,11 @@ func (c canary) Parse(ing *networking.Ingress) (interface{}, error) {
 		config.Weight = 0
 	}
 
+	config.WeightTotal, err = parser.GetIntAnnotation("canary-weight-total", ing)
+	if err != nil {
+		config.WeightTotal = 100
+	}
+
 	config.Header, err = parser.GetStringAnnotation("canary-by-header", ing)
 	if err != nil {
 		config.Header = ""

internal/ingress/controller/controller.go

@@ -910,6 +910,7 @@ func (n *NGINXController) createUpstreams(data []*ingress.Ingress, du *ingress.B
 				upstreams[defBackend].NoServer = true
 				upstreams[defBackend].TrafficShapingPolicy = ingress.TrafficShapingPolicy{
 					Weight:        anns.Canary.Weight,
+					WeightTotal:   anns.Canary.WeightTotal,
 					Header:        anns.Canary.Header,
 					HeaderValue:   anns.Canary.HeaderValue,
 					HeaderPattern: anns.Canary.HeaderPattern,

internal/ingress/types.go

@@ -111,10 +111,15 @@ type Backend struct {
 // alternative backend
 // +k8s:deepcopy-gen=true
 type TrafficShapingPolicy struct {
-	// Weight (0-100) of traffic to redirect to the backend.
-	// e.g. Weight 20 means 20% of traffic will be redirected to the backend and 80% will remain
-	// with the other backend. 0 weight will not send any traffic to this backend
+	// Weight (0-<WeightTotal>) of traffic to redirect to the backend.
+	// e.g. <WeightTotal> defaults to 100, weight 20 means 20% of traffic will be
+	// redirected to the backend and 80% will remain with the other backend. If
+	// <WeightTotal> is set to 1000, weight 2 means 0.2% of traffic will be
+	// redirected to the backend and 99.8% will remain with the other backend.
+	// 0 weight will not send any traffic to this backend
 	Weight int `json:"weight"`
+	// The total weight of traffic (>= 100). If unspecified, it defaults to 100.
+	WeightTotal int `json:"weightTotal"`
 	// Header on which to redirect requests to this backend
 	Header string `json:"header"`
 	// HeaderValue on which to redirect requests to this backend

rootfs/etc/nginx/lua/balancer.lua

@@ -259,7 +259,11 @@ local function route_to_alternative_balancer(balancer)
     end
   end
 
-  if math.random(100) <= traffic_shaping_policy.weight then
+  local weightTotal = 100
+  if traffic_shaping_policy.weightTotal ~= nil and traffic_shaping_policy.weightTotal > 100 then
+    weightTotal = traffic_shaping_policy.weightTotal
+  end
+  if math.random(weightTotal) <= traffic_shaping_policy.weight then
     return true
   end
 

rootfs/etc/nginx/lua/test/balancer_test.lua

@@ -203,6 +203,20 @@ describe("Balancer", function()
           balancer.sync_backend(backend)
           assert.equal(false, balancer.route_to_alternative_balancer(_primaryBalancer))
         end)
+
+        it("returns true when weight is 1000 and weight total is 1000", function()
+          backend.trafficShapingPolicy.weight = 1000
+          backend.trafficShapingPolicy.weightTotal = 1000
+          balancer.sync_backend(backend)
+          assert.equal(true, balancer.route_to_alternative_balancer(_primaryBalancer))
+        end)
+
+        it("returns false when weight is 0 and weight total is 1000", function()
+          backend.trafficShapingPolicy.weight = 1000
+          backend.trafficShapingPolicy.weightTotal = 1000
+          balancer.sync_backend(backend)
+          assert.equal(true, balancer.route_to_alternative_balancer(_primaryBalancer))
+        end)
       end)
 
       describe("canary by cookie", function()

test/e2e/annotations/canary.go

@@ -773,6 +773,39 @@ var _ = framework.DescribeAnnotation("canary-*", func() {
 				Contains(canaryService)
 		})
 
+		ginkgo.It("should route requests only to canary if canary weight is equal to canary weight total", func() {
+			host := "foo"
+			annotations := map[string]string{}
+
+			ing := framework.NewSingleIngress(host, "/", host,
+				f.Namespace, framework.EchoService, 80, annotations)
+			f.EnsureIngress(ing)
+
+			f.WaitForNginxServer(host,
+				func(server string) bool {
+					return strings.Contains(server, "server_name foo")
+				})
+
+			canaryIngName := fmt.Sprintf("%v-canary", host)
+			canaryAnnotations := map[string]string{
+				"nginx.ingress.kubernetes.io/canary":              "true",
+				"nginx.ingress.kubernetes.io/canary-weight":       "1000",
+				"nginx.ingress.kubernetes.io/canary-weight-total": "1000",
+			}
+
+			canaryIng := framework.NewSingleIngress(canaryIngName, "/", host,
+				f.Namespace, canaryService, 80, canaryAnnotations)
+			f.EnsureIngress(canaryIng)
+
+			f.HTTPTestClient().
+				GET("/").
+				WithHeader("Host", host).
+				Expect().
+				Status(http.StatusOK).
+				Body().
+				Contains(canaryService)
+		})
+
 		ginkgo.It("should route requests evenly split between mainline and canary if canary weight is 50", func() {
 			host := "foo"
 			annotations := map[string]string{}