Allowing setting minReplicas for IG router. (kserve#2679)

Also added some logging for IG router to log step execution time.

Signed-off-by: rachitchauhan43 <[email protected]>

cmd/router/main.go

@@ -41,6 +41,8 @@ import (
 var log = logf.Log.WithName("InferenceGraphRouter")
 
 func callService(serviceUrl string, input []byte, headers http.Header) ([]byte, error) {
+	defer timeTrack(time.Now(), "step", serviceUrl)
+	log.Info("Entering callService", "url", serviceUrl)
 	req, err := http.NewRequest("POST", serviceUrl, bytes.NewBuffer(input))
 	for _, h := range headersToPropagate {
 		if values, ok := headers[h]; ok {
@@ -90,13 +92,13 @@ func pickupRouteByCondition(input []byte, routes []v1alpha1.InferenceStep) *v1al
 	return nil
 }
 
-func timeTrack(start time.Time, name string) {
+func timeTrack(start time.Time, nodeOrStep string, name string) {
 	elapsed := time.Since(start)
-	log.Info("elapsed time", "node", name, "time", elapsed)
+	log.Info("elapsed time", nodeOrStep, name, "time", elapsed)
 }
 
 func routeStep(nodeName string, graph v1alpha1.InferenceGraphSpec, input []byte, headers http.Header) ([]byte, error) {
-	defer timeTrack(time.Now(), nodeName)
+	defer timeTrack(time.Now(), "node", nodeName)
 	currentNode := graph.Nodes[nodeName]
 
 	if currentNode.RouterType == v1alpha1.Splitter {
@@ -195,12 +197,16 @@ func graphHandler(w http.ResponseWriter, req *http.Request) {
 
 var (
 	jsonGraph          = flag.String("graph-json", "", "serialized json graph def")
-	headersToPropagate = strings.Split(os.Getenv(constants.RouterHeadersPropagateEnvVar), ",")
+	headersToPropagate []string
 )
 
 func main() {
 	flag.Parse()
 	logf.SetLogger(zap.New())
+	if headersToPropagateEnvVar, ok := os.LookupEnv(constants.RouterHeadersPropagateEnvVar); ok {
+		log.Info("These headers will be propagated by the router to all the steps.", "headersToPropagateEnvVar", headersToPropagateEnvVar)
+		headersToPropagate = strings.Split(headersToPropagateEnvVar, ",")
+	}
 	inferenceGraph = &v1alpha1.InferenceGraphSpec{}
 	err := json.Unmarshal([]byte(*jsonGraph), inferenceGraph)
 	if err != nil {

cmd/router/main_test.go

@@ -9,9 +9,15 @@ import (
 	"knative.dev/pkg/apis"
 	"net/http"
 	"net/http/httptest"
+	logf "sigs.k8s.io/controller-runtime/pkg/log"
+	"sigs.k8s.io/controller-runtime/pkg/log/zap"
 	"testing"
 )
 
+func init() {
+	logf.SetLogger(zap.New())
+}
+
 func TestSimpleModelChainer(t *testing.T) {
 	// Start a local HTTP server
 	model1 := httptest.NewServer(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {