Implement rate limit

docs/content/configuration.md

@@ -69,3 +69,17 @@ The circuit breaker protects your system from stacking requests to unhealthy ser
 When your system is healthy, the circuit is closed (normal operations). When your system becomes unhealthy, the circuit opens, and requests are no longer forwarded (but handled by a fallback mechanism).
 
 All configuration options are available [here](https://docs.traefik.io/v2.0/middlewares/circuitbreaker/#configuration-options)
+
+### Rate Limit
+
+Rate limiting can be enabled by using the following annotations:
+
+```yaml
+maesh.containo.us/ratelimit-average: "100"
+maesh.containo.us/ratelimit-burst: "200"
+```
+
+These annotation sets average and burst requests per second limit for the service.
+Please note that this value is a string, and needs to be quoted.
+
+Further details about the rate limiting can be found [here](https://docs.traefik.io/v2.0/middlewares/ratelimit/#configuration-options)

internal/k8s/constants.go

@@ -17,6 +17,10 @@ const (
 	AnnotationRetryAttempts = baseAnnotation + "retry-attempts"
 	// AnnotationCircuitBreakerExpression circuit breaker expression annotation.
 	AnnotationCircuitBreakerExpression = baseAnnotation + "circuit-breaker-expression"
+	// AnnotationRateLimitAverage sets the average value for rate limiting.
+	AnnotationRateLimitAverage = baseAnnotation + "ratelimit-average"
+	// AnnotationRateLimitBurst sets the burst value for rate limiting.
+	AnnotationRateLimitBurst = baseAnnotation + "ratelimit-burst"
 
 	// ServiceTypeHTTP HTTP service type.
 	ServiceTypeHTTP string = "http"

internal/providers/kubernetes/provider.go

@@ -174,13 +174,15 @@ func (p *Provider) BuildConfig() (*dynamic.Configuration, error) {
 func (p *Provider) buildHTTPMiddlewares(annotations map[string]string) *dynamic.Middleware {
 	circuitBreaker := buildCircuitBreakerMiddleware(annotations)
 	retry := buildRetryMiddleware(annotations)
+	rateLimit := buildRateLimitMiddleware(annotations)
 
-	if circuitBreaker == nil && retry == nil {
+	if circuitBreaker == nil && retry == nil && rateLimit == nil {
 		return nil
 	}
 
 	return &dynamic.Middleware{
 		CircuitBreaker: circuitBreaker,
+		RateLimit:      rateLimit,
 		Retry:          retry,
 	}
 }
@@ -215,6 +217,29 @@ func buildRetryMiddleware(annotations map[string]string) *dynamic.Retry {
 	return nil
 }
 
+func buildRateLimitMiddleware(annotations map[string]string) *dynamic.RateLimit {
+	if annotations[k8s.AnnotationRateLimitAverage] != "" || annotations[k8s.AnnotationRateLimitBurst] != "" {
+		rlAverage, err := strconv.Atoi(annotations[k8s.AnnotationRateLimitAverage])
+		if err != nil {
+			log.Errorf("Could not parse rateLimit average annotation: %v", err)
+		}
+
+		rlBurst, err := strconv.Atoi(annotations[k8s.AnnotationRateLimitBurst])
+		if err != nil {
+			log.Errorf("Could not parse rateLimit burst annotation: %v", err)
+		}
+
+		if rlAverage > 0 && rlBurst > 1 {
+			return &dynamic.RateLimit{
+				Average: int64(rlAverage),
+				Burst:   int64(rlBurst),
+			}
+		}
+	}
+
+	return nil
+}
+
 func (p *Provider) getMeshPort(serviceName, serviceNamespace string, servicePort int32) int {
 	for port, v := range p.tcpStateTable.Table {
 		if v.Name == serviceName && v.Namespace == serviceNamespace && v.Port == servicePort {

internal/providers/kubernetes/provider_test.go

@@ -554,6 +554,35 @@ func TestBuildHTTPMiddlewares(t *testing.T) {
 			},
 			expected: nil,
 		},
+		{
+			desc: "parseable rate limit",
+			annotations: map[string]string{
+				k8s.AnnotationRateLimitAverage: "100",
+				k8s.AnnotationRateLimitBurst:   "200",
+			},
+			expected: &dynamic.Middleware{
+				RateLimit: &dynamic.RateLimit{
+					Average: 100,
+					Burst:   200,
+				},
+			},
+		},
+		{
+			desc: "empty rate limit",
+			annotations: map[string]string{
+				k8s.AnnotationRateLimitAverage: "",
+				k8s.AnnotationRateLimitBurst:   "",
+			},
+			expected: nil,
+		},
+		{
+			desc: "unparseable rate limit",
+			annotations: map[string]string{
+				k8s.AnnotationRateLimitAverage: "foo",
+				k8s.AnnotationRateLimitBurst:   "bar",
+			},
+			expected: nil,
+		},
 	}
 
 	for _, test := range testCases {