feat: add basic dns client to kapinger (#859)

# Description

Simple nslookup on burst

## Related Issue



## Checklist

- [ ] I have read the [contributing
documentation](https://retina.sh/docs/contributing).
- [ ] I signed and signed-off the commits (`git commit -S -s ...`). See
[this
documentation](https://docs.github.com/en/authentication/managing-commit-signature-verification/about-commit-signature-verification)
on signing commits.
- [ ] I have correctly attributed the author(s) of the code.
- [ ] I have tested the changes locally.
- [ ] I have followed the project's style guidelines.
- [ ] I have updated the documentation, if necessary.
- [ ] I have added tests, if applicable.

## Screenshots (if applicable) or Testing Completed

Please add any relevant screenshots or GIFs to showcase the changes
made.

## Additional Notes

Add any additional notes or context about the pull request here.

---

Please refer to the [CONTRIBUTING.md](../CONTRIBUTING.md) file for more
information on how to contribute to this project.

Makefile

@@ -194,7 +194,7 @@ RETINA_OPERATOR_IMAGE			= $(IMAGE_NAMESPACE)/retina-operator
 RETINA_INTEGRATION_TEST_IMAGE	= $(IMAGE_NAMESPACE)/retina-integration-test
 RETINA_PROTO_IMAGE				= $(IMAGE_NAMESPACE)/retina-proto-gen
 RETINA_GO_GEN_IMAGE				= $(IMAGE_NAMESPACE)/retina-go-gen
-KAPINGER_IMAGE 					= $(IMAGE_NAMESPACE)/kapinger
+KAPINGER_IMAGE 					= kapinger
 
 skopeo-export: # util target to copy a container from containers-storage to the docker daemon.
 	skopeo copy \
@@ -307,6 +307,15 @@ retina-operator-image:  ## build the retina linux operator image.
 			APP_INSIGHTS_ID=$(APP_INSIGHTS_ID) \
 			CONTEXT_DIR=$(REPO_ROOT)
 
+kapinger-image: 
+	docker buildx build --builder retina --platform windows/amd64 --target windows-amd64 -t $(IMAGE_REGISTRY)/$(KAPINGER_IMAGE):$(TAG)-windows-amd64  ./hack/tools/kapinger/ --push
+	docker buildx build --builder retina --platform linux/amd64 --target linux-amd64 -t $(IMAGE_REGISTRY)/$(KAPINGER_IMAGE):$(TAG)-linux-amd64  ./hack/tools/kapinger/ --push
+	docker buildx build --builder retina --platform linux/arm64 --target linux-arm64 -t $(IMAGE_REGISTRY)/$(KAPINGER_IMAGE):$(TAG)-linux-arm64  ./hack/tools/kapinger/ --push
+	docker buildx imagetools create -t $(IMAGE_REGISTRY)/$(KAPINGER_IMAGE):$(TAG) \
+		$(IMAGE_REGISTRY)/$(KAPINGER_IMAGE):$(TAG)-windows-amd64 \
+		$(IMAGE_REGISTRY)/$(KAPINGER_IMAGE):$(TAG)-linux-amd64 \
+		$(IMAGE_REGISTRY)/$(KAPINGER_IMAGE):$(TAG)-linux-arm64
+
 proto-gen: ## generate protobuf code
 	docker build --platform=linux/amd64 \
 		-t $(IMAGE_REGISTRY)/$(RETINA_PROTO_IMAGE):$(RETINA_PLATFORM_TAG) \

hack/tools/kapinger/.dockerignore

@@ -0,0 +1 @@
+Dockerfile

hack/tools/kapinger/Dockerfile

@@ -1,12 +1,30 @@
-FROM mcr.microsoft.com/oss/go/microsoft/golang:1.22 AS builder
+FROM --platform=linux/amd64 mcr.microsoft.com/oss/go/microsoft/golang:1.22 AS builder
 
 WORKDIR /build
 ADD . .
 RUN go mod download 
 
+# Build for Linux
 RUN CGO_ENABLED=0 GOOS=linux go build -o kapinger .
 
-FROM scratch
-WORKDIR /build
+# Build for Windows
+RUN CGO_ENABLED=0 GOOS=windows go build -o kapinger.exe .
+
+# Build for ARM64 Linux
+RUN CGO_ENABLED=0 GOOS=linux GOARCH=arm64 go build -o kapinger-arm64 .
+
+FROM --platform=linux/amd64 scratch AS linux-amd64
+WORKDIR /app
 COPY --from=builder /build/kapinger .
 CMD ["./kapinger"]
+
+FROM --platform=windows/amd64 mcr.microsoft.com/windows/servercore:ltsc2022 AS windows-amd64
+WORKDIR /app
+COPY --from=builder /build/kapinger.exe .
+ENTRYPOINT [ "cmd.exe" ]
+CMD [ "/c", "kapinger.exe" ]
+
+FROM --platform=linux/arm64 scratch AS linux-arm64
+WORKDIR /app
+COPY --from=builder /build/kapinger-arm64 .
+CMD ["./kapinger-arm64"]

hack/tools/kapinger/clients/client.go

@@ -0,0 +1,9 @@
+package clients
+
+import (
+	"context"
+)
+
+type Client interface {
+	MakeRequests(ctx context.Context) error
+}

hack/tools/kapinger/clients/dns.go

@@ -0,0 +1,45 @@
+package clients
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"net"
+	"time"
+)
+
+type KapingerDNSClient struct {
+	volume   int
+	interval time.Duration
+}
+
+func NewKapingerDNSClient(volume int, interval time.Duration) *KapingerDNSClient {
+	return &KapingerDNSClient{
+		interval: time.Duration(interval),
+		volume:   volume,
+	}
+}
+
+func (k *KapingerDNSClient) MakeRequests(ctx context.Context) error {
+	ticker := time.NewTicker(k.interval)
+	for {
+		select {
+		case <-ctx.Done():
+			log.Printf("DNS client context done")
+			return nil
+		case <-ticker.C:
+			go func() {
+				for i := 0; i < k.volume; i++ {
+					domain := "retina.sh"
+
+					ips, err := net.LookupIP(domain)
+					if err != nil {
+						fmt.Printf("dns client: could not get IPs: %v\n", err)
+						return
+					}
+					log.Printf("dns client: resolved %s to %s\n", domain, ips)
+				}
+			}()
+		}
+	}
+}

hack/tools/kapinger/clients/http.go

@@ -28,12 +28,14 @@ type KapingerHTTPClient struct {
 	client        http.Client
 	clientset     *kubernetes.Clientset
 	labelselector string
-	ips           []string
+	urls          []string
 	port          int
 	targettype    TargetType
+	volume        int
+	interval      time.Duration
 }
 
-func NewKapingerHTTPClient(clientset *kubernetes.Clientset, labelselector string, httpPort int) (*KapingerHTTPClient, error) {
+func NewKapingerHTTPClient(clientset *kubernetes.Clientset, labelselector string, volume int, interval time.Duration, httpPort int) (*KapingerHTTPClient, error) {
 	k := KapingerHTTPClient{
 		client: http.Client{
 			Transport: &http.Transport{
@@ -44,6 +46,8 @@ func NewKapingerHTTPClient(clientset *kubernetes.Clientset, labelselector string
 		labelselector: labelselector,
 		clientset:     clientset,
 		port:          httpPort,
+		volume:        volume,
+		interval:      interval,
 	}
 
 	targettype := os.Getenv(envTargetType)
@@ -53,105 +57,114 @@ func NewKapingerHTTPClient(clientset *kubernetes.Clientset, labelselector string
 		k.targettype = Service
 	}
 
-	err := k.getIPS()
+	var err error
+	switch k.targettype {
+	case Service:
+		k.urls, err = k.getServiceURLs()
+		if err != nil {
+			return nil, fmt.Errorf("error getting service URLs: %w", err)
+		}
+
+	case Pod:
+		k.urls, err = k.getPodURLs()
+
+	default:
+		return nil, fmt.Errorf("env TARGET_TYPE must be \"service\" or \"pod\"")
+	}
 	if err != nil {
 		return nil, fmt.Errorf("error getting IPs: %w", err)
 	}
 
 	return &k, nil
 }
-func (k *KapingerHTTPClient) MakeRequests(ctx context.Context, volume int, interval time.Duration) error {
-	ticker := time.NewTicker(interval)
+
+func (k *KapingerHTTPClient) MakeRequests(ctx context.Context) error {
+	ticker := time.NewTicker(k.interval)
 	for {
 		select {
 		case <-ctx.Done():
 			log.Printf("HTTP client context done")
 			return nil
 		case <-ticker.C:
 			go func() {
-				for i := 0; i < volume; i++ {
-					err := k.makeRequest()
-					if err != nil {
-						log.Printf("error making request: %v", err)
+				for i := 0; i < k.volume; i++ {
+					for _, url := range k.urls {
+						body, err := k.makeRequest(ctx, url)
+						if err != nil {
+							log.Printf("error making request: %v", err)
+						} else {
+							log.Printf("response from %s: %s\n", url, string(body))
+						}
 					}
 				}
 			}()
 		}
 	}
 }
 
-func (k *KapingerHTTPClient) makeRequest() error {
-	for _, ip := range k.ips {
-		url := fmt.Sprintf("http://%s:%d", ip, k.port)
-		req, err := http.NewRequest("GET", url, nil)
-		if err != nil {
-			return err
-		}
-
-		// Set the "Connection" header to "close"
-		req.Header.Set("Connection", "close")
+func (k *KapingerHTTPClient) makeRequest(ctx context.Context, url string) ([]byte, error) {
+	req, err := http.NewRequestWithContext(ctx, "GET", url, http.NoBody)
+	if err != nil {
+		return nil, err
+	}
 
-		// Send the request
-		resp, err := k.client.Do(req)
-		if err != nil {
-			return err
-		}
-		defer resp.Body.Close()
+	// Set the "Connection" header to "close"
+	req.Header.Set("Connection", "close")
 
-		body, err := io.ReadAll(resp.Body)
-		if err != nil {
-			log.Fatalf("Error reading response body from %s: %v", url, err)
-			return err
-		}
-		log.Printf("Response from %s: %s\n", url, string(body))
+	// Send the request
+	resp, err := k.client.Do(req)
+	if err != nil {
+		return nil, err
 	}
-	return nil
-}
-
-func (k *KapingerHTTPClient) getIPS() error {
-	ips := []string{}
+	defer resp.Body.Close()
 
-	switch k.targettype {
-	case Service:
-		services, err := k.clientset.CoreV1().Services(corev1.NamespaceAll).List(context.Background(), metav1.ListOptions{
-			LabelSelector: k.labelselector,
-		})
-		if err != nil {
-			return fmt.Errorf("error getting services: %w", err)
-		}
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		log.Fatalf("Error reading response body from %s: %v", url, err)
+		return nil, err
+	}
 
-		// Extract the Service cluster IP addresses
+	return body, nil
+}
 
-		for _, svc := range services.Items {
-			ips = append(ips, svc.Spec.ClusterIP)
-		}
-		log.Println("using service IPs:", ips)
+func (k *KapingerHTTPClient) getServiceURLs() ([]string, error) {
+	urls := []string{}
+	services, err := k.clientset.CoreV1().Services(corev1.NamespaceAll).List(context.Background(), metav1.ListOptions{
+		LabelSelector: k.labelselector,
+	})
+	if err != nil {
+		return urls, fmt.Errorf("error getting services: %w", err)
+	}
 
-	case Pod:
-		err := waitForPodsRunning(k.clientset, k.labelselector)
-		if err != nil {
-			return fmt.Errorf("error waiting for pods to be in Running state: %w", err)
-		}
+	// Extract the Service cluster IP addresses
 
-		// Get all pods in the cluster with label app=agnhost
-		pods, err := k.clientset.CoreV1().Pods(corev1.NamespaceAll).List(context.Background(), metav1.ListOptions{
-			LabelSelector: k.labelselector,
-		})
-		if err != nil {
-			return fmt.Errorf("error getting pods: %w", err)
-		}
+	for svc := range services.Items {
+		urls = append(urls, fmt.Sprintf("http://%s.%s.svc.cluster.local:%d/", services.Items[svc].Name, services.Items[svc].Namespace, k.port))
+	}
+	log.Printf("using service URLs: %+v", urls)
+	return urls, nil
+}
 
-		for _, pod := range pods.Items {
-			ips = append(ips, pod.Status.PodIP)
-		}
+func (k *KapingerHTTPClient) getPodURLs() ([]string, error) {
+	urls := []string{}
+	err := waitForPodsRunning(k.clientset, k.labelselector)
+	if err != nil {
+		return nil, fmt.Errorf("error waiting for pods to be in Running state: %w", err)
+	}
 
-		log.Printf("using pod IPs: %v", ips)
-	default:
-		return fmt.Errorf("env TARGET_TYPE must be \"service\" or \"pod\"")
+	// Get all pods in the cluster with label app=agnhost
+	pods, err := k.clientset.CoreV1().Pods(corev1.NamespaceAll).List(context.Background(), metav1.ListOptions{
+		LabelSelector: k.labelselector,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("error getting pods: %w", err)
 	}
 
-	k.ips = ips
-	return nil
+	for _, pod := range pods.Items {
+		urls = append(urls, fmt.Sprintf("http://%s:%d", pod.Status.PodIP, k.port))
+	}
+	log.Printf("using pod URL's: %+v", urls)
+	return urls, nil
 }
 
 // waitForPodsRunning waits for all pods with the specified label to be in the Running phase

hack/tools/kapinger/go.mod

@@ -28,6 +28,7 @@ require (
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
 	golang.org/x/net v0.23.0 // indirect
 	golang.org/x/oauth2 v0.10.0 // indirect
+	golang.org/x/sync v0.8.0 // indirect
 	golang.org/x/sys v0.18.0 // indirect
 	golang.org/x/term v0.18.0 // indirect
 	golang.org/x/text v0.14.0 // indirect

hack/tools/kapinger/go.sum

@@ -91,6 +91,8 @@ golang.org/x/oauth2 v0.10.0/go.mod h1:kTpgurOux7LqtuxjuyZa4Gj2gdezIt/jQtGnNFfypQ
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20201020160332-67f06af15bc9/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.8.0 h1:3NFvSEYkUoMifnESzZl15y791HH1qU2xm6eCJU5ZPXQ=
+golang.org/x/sync v0.8.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=