Add kubernetes QPS and Burst limit configuration (#2899)

Added configurable kubernetes client limits burst and QPS
Default QPS 200 and burst 500. Configurable via helm chart values.

Signed-off-by: Sanket Sudake <sanketsudake@gmail.com>

pkg/crd/client.go

@@ -35,6 +35,11 @@ import (
 	"github.com/fission/fission/pkg/utils"
 )
 
+const (
+	EnvKubeClientQps   = "KUBE_CLIENT_QPS"
+	EnvKubeClientBurst = "KUBE_CLIENT_BURST"
+)
+
 type (
 	ClientGeneratorInterface interface {
 		GetRestConfig() (*rest.Config, error)
@@ -60,6 +65,20 @@ func (cg *ClientGenerator) getRestConfig() (*rest.Config, error) {
 	if err != nil {
 		return nil, err
 	}
+
+	qps, _ := utils.GetUIntValueFromEnv(EnvKubeClientQps)
+	burst, _ := utils.GetIntValueFromEnv(EnvKubeClientBurst)
+
+	// Set QPS and Burst to higher values to avoid throttling
+	if qps == 0 {
+		qps = 200
+	}
+	if burst == 0 {
+		burst = 500
+	}
+	cg.restConfig.QPS = float32(qps)
+	cg.restConfig.Burst = burst
+
 	return cg.restConfig, nil
 }
 

pkg/utils/utils.go

@@ -232,6 +232,18 @@ func GetUIntValueFromEnv(envVar string) (uint, error) {
 	return uint(value), nil
 }
 
+func GetIntValueFromEnv(envVar string) (int, error) {
+	s, err := GetStringValueFromEnv(envVar)
+	if err != nil {
+		return 0, err
+	}
+	value, err := strconv.Atoi(s)
+	if err != nil {
+		return 0, err
+	}
+	return value, nil
+}
+
 func FindFreePort() (int, error) {
 	listener, err := net.Listen("tcp", ":0")
 	if err != nil {

pkg/utils/utils_test.go

@@ -162,3 +162,48 @@ func TestGetUIntValueFromEnv(t *testing.T) {
 		})
 	}
 }
+
+func TestGetIntValueFromEnv(t *testing.T) {
+	varName := "TEST_VAR"
+	tests := []struct {
+		name    string
+		value   string
+		want    int
+		wantErr bool
+	}{
+		{
+			name:    "empty string case",
+			value:   "",
+			want:    0,
+			wantErr: true,
+		},
+		{
+			name:    "string case",
+			value:   "test string",
+			want:    0,
+			wantErr: true,
+		},
+		{
+			name:    "not int case",
+			value:   "-100",
+			want:    -100,
+			wantErr: false,
+		},
+		{
+			name:    "int case",
+			value:   "7",
+			want:    7,
+			wantErr: false,
+		}}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			os.Setenv(varName, tt.value)
+			got, err := GetIntValueFromEnv(varName)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("GetIntValueFromEnv() error = %v, wantErr %v, got %d", err, tt.wantErr, got)
+				return
+			}
+		})
+	}
+}