Split implementations from generic code

core/pkg/ingress/annotations/ratelimit/main.go

@@ -0,0 +1,99 @@
+/*
+Copyright 2016 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package ratelimit
+
+import (
+	"errors"
+	"fmt"
+
+	"k8s.io/ingress/core/pkg/ingress/annotations/parser"
+
+	"k8s.io/kubernetes/pkg/apis/extensions"
+)
+
+const (
+	limitIP  = "ingress.kubernetes.io/limit-connections"
+	limitRPS = "ingress.kubernetes.io/limit-rps"
+
+	// allow 5 times the specified limit as burst
+	defBurst = 5
+
+	// 1MB -> 16 thousand 64-byte states or about 8 thousand 128-byte states
+	// default is 5MB
+	defSharedSize = 5
+)
+
+var (
+	// ErrInvalidRateLimit is returned when the annotation caontains invalid values
+	ErrInvalidRateLimit = errors.New("invalid rate limit value. Must be > 0")
+)
+
+// RateLimit returns rate limit configuration for an Ingress rule
+// Is possible to limit the number of connections per IP address or
+// connections per second.
+// Note: Is possible to specify both limits
+type RateLimit struct {
+	// Connections indicates a limit with the number of connections per IP address
+	Connections Zone
+	// RPS indicates a limit with the number of connections per second
+	RPS Zone
+}
+
+// Zone returns information about the NGINX rate limit (limit_req_zone)
+// http://nginx.org/en/docs/http/ngx_http_limit_req_module.html#limit_req_zone
+type Zone struct {
+	Name  string
+	Limit int
+	Burst int
+	// SharedSize amount of shared memory for the zone
+	SharedSize int
+}
+
+// ParseAnnotations parses the annotations contained in the ingress
+// rule used to rewrite the defined paths
+func ParseAnnotations(ing *extensions.Ingress) (*RateLimit, error) {
+	if ing.GetAnnotations() == nil {
+		return &RateLimit{}, parser.ErrMissingAnnotations
+	}
+
+	rps, _ := parser.GetIntAnnotation(limitRPS, ing)
+	conn, _ := parser.GetIntAnnotation(limitIP, ing)
+
+	if rps == 0 && conn == 0 {
+		return &RateLimit{
+			Connections: Zone{},
+			RPS:         Zone{},
+		}, ErrInvalidRateLimit
+	}
+
+	zoneName := fmt.Sprintf("%v_%v", ing.GetNamespace(), ing.GetName())
+
+	return &RateLimit{
+		Connections: Zone{
+			Name:       fmt.Sprintf("%v_conn", zoneName),
+			Limit:      conn,
+			Burst:      conn * defBurst,
+			SharedSize: defSharedSize,
+		},
+		RPS: Zone{
+			Name:       fmt.Sprintf("%v_rps", zoneName),
+			Limit:      rps,
+			Burst:      conn * defBurst,
+			SharedSize: defSharedSize,
+		},
+	}, nil
+}