[feat] ability to customize kube client qps (#101)

* [feat] ability to customize kube client qps

Signed-off-by: Derek Brown <6845676+DerekTBrown@users.noreply.github.com>

* fix log line type

Signed-off-by: Derek Brown <6845676+DerekTBrown@users.noreply.github.com>

---------

Signed-off-by: Derek Brown <6845676+DerekTBrown@users.noreply.github.com>

Author: DerekTBrown

docs/features/cli-options.md

@@ -0,0 +1,16 @@
+# CLI Options
+
+## Increasing Kubernetes API Server Request QPS and Burst
+The `kubeClientQPS` and `kubeClientBurst` options configure the behavior of the Kubernetes client. These
+values may need to be increased if you operate Argo Rollouts in a large cluster.  These values can be specified
+using the `args` block of the plugin configuration:
+
+```yaml
+  trafficRouterPlugins:
+    trafficRouterPlugins: |-
+      - name: "argoproj-labs/gatewayAPI"
+        location: "https://github.com/argoproj-labs/rollouts-plugin-trafficrouter-gatewayapi/releases/download/v0.4.0/gatewayapi-plugin-linux-amd64"
+        args:
+        - "-kubeClientQPS=40"
+        - "-kubeClientBurst=80"
+```

main.go

@@ -1,6 +1,8 @@
 package main
 
 import (
+	"flag"
+
 	"github.com/argoproj-labs/rollouts-plugin-trafficrouter-gatewayapi/internal/utils"
 	"github.com/argoproj-labs/rollouts-plugin-trafficrouter-gatewayapi/pkg/plugin"
 
@@ -19,12 +21,24 @@ var handshakeConfig = goPlugin.HandshakeConfig{
 }
 
 func main() {
+	// Define and parse flags for your command line options:
+	kubeClientQPS := flag.Int("kubeClientQPS", 5, "The QPS to use for the Kubernetes client.")
+	kubeClientBurst := flag.Int("kubeClientBurst", 10, "The Burst to use for the Kubernetes client.")
+	flag.Parse()
+
+	// Create the plugin implementation, injecting command line options:
 	rpcPluginImp := &plugin.RpcPlugin{
+		CommandLineOpts: plugin.CommandLineOpts{
+			KubeClientQPS:   float32(*kubeClientQPS),
+			KubeClientBurst: *kubeClientBurst,
+		},
 		LogCtx: utils.SetupLog(),
 	}
+
 	pluginMap := map[string]goPlugin.Plugin{
 		"RpcTrafficRouterPlugin": &rolloutsPlugin.RpcTrafficRouterPlugin{Impl: rpcPluginImp},
 	}
+
 	goPlugin.Serve(&goPlugin.ServeConfig{
 		HandshakeConfig: handshakeConfig,
 		Plugins:         pluginMap,

pkg/plugin/plugin.go

@@ -4,13 +4,14 @@ import (
 	"encoding/json"
 	"fmt"
 
-	"github.com/argoproj-labs/rollouts-plugin-trafficrouter-gatewayapi/internal/defaults"
-	"github.com/argoproj-labs/rollouts-plugin-trafficrouter-gatewayapi/internal/utils"
 	"github.com/argoproj/argo-rollouts/pkg/apis/rollouts/v1alpha1"
 	pluginTypes "github.com/argoproj/argo-rollouts/utils/plugin/types"
 	"github.com/go-playground/validator/v10"
 	"k8s.io/client-go/kubernetes"
 	gatewayApiClientset "sigs.k8s.io/gateway-api/pkg/client/clientset/versioned"
+
+	"github.com/argoproj-labs/rollouts-plugin-trafficrouter-gatewayapi/internal/defaults"
+	"github.com/argoproj-labs/rollouts-plugin-trafficrouter-gatewayapi/internal/utils"
 )
 
 const (
@@ -19,6 +20,8 @@ const (
 )
 
 func (r *RpcPlugin) InitPlugin() pluginTypes.RpcError {
+	log := utils.SetupLog()
+
 	if r.IsTest {
 		return pluginTypes.RpcError{}
 	}
@@ -28,6 +31,17 @@ func (r *RpcPlugin) InitPlugin() pluginTypes.RpcError {
 			ErrorString: err.Error(),
 		}
 	}
+
+	// Configure command-line overrides for the Kubernetes client:
+	if r.CommandLineOpts.KubeClientQPS != 0 {
+		log.Infof("KubeClientQPS set to: %f", r.CommandLineOpts.KubeClientQPS)
+		kubeConfig.QPS = r.CommandLineOpts.KubeClientQPS
+	}
+	if r.CommandLineOpts.KubeClientBurst != 0 {
+		log.Infof("KubeClientBurst set to: %d", r.CommandLineOpts.KubeClientBurst)
+		kubeConfig.Burst = r.CommandLineOpts.KubeClientBurst
+	}
+
 	gatewayAPIClientset, err := gatewayApiClientset.NewForConfig(kubeConfig)
 	if err != nil {
 		return pluginTypes.RpcError{

pkg/plugin/types.go

@@ -13,7 +13,13 @@ import (
 	gatewayApiClientv1alpha2 "sigs.k8s.io/gateway-api/pkg/client/clientset/versioned/typed/apis/v1alpha2"
 )
 
+type CommandLineOpts struct {
+	KubeClientQPS   float32
+	KubeClientBurst int
+}
+
 type RpcPlugin struct {
+	CommandLineOpts      CommandLineOpts
 	HTTPRouteClient      gatewayApiClientv1.HTTPRouteInterface
 	TCPRouteClient       gatewayApiClientv1alpha2.TCPRouteInterface
 	GRPCRouteClient      gatewayApiClientv1.GRPCRouteInterface