Add agent

cmd/spoke-agent/main.go

@@ -0,0 +1,107 @@
+package main
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"encoding/json"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"os"
+	"time"
+)
+
+func main() {
+	logger := log.New(os.Stdout, "main: ", log.LstdFlags|log.Lshortfile)
+
+	client, err := HubClient()
+	if err != nil {
+		logger.Fatal(err)
+	}
+
+	registered := false
+	for !registered {
+		state := getCurrentState(client, logger)
+		switch state {
+		case "pending_approval":
+			logger.Println("waiting for approval")
+		case "registered":
+			registered = true
+			logger.Println("application registered!")
+		default:
+			logger.Println("retrying")
+
+		}
+		time.Sleep(3 * time.Second)
+	}
+
+}
+
+func HubClient() (*http.Client, error) {
+	caFile, err := os.Open("./certs/ca.pem")
+	if err != nil {
+		return nil, fmt.Errorf("failed to open ca cert: %w", err)
+	}
+	caCert, err := io.ReadAll(caFile)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read the ca cert: %w", err)
+	}
+
+	pool := x509.NewCertPool()
+	pool.AppendCertsFromPEM(caCert)
+
+	certPath := "./certs/app1.pem"
+	keyPath := "./certs/app1-key.pem"
+
+	cert, err := tls.LoadX509KeyPair(certPath, keyPath)
+	if err != nil {
+		return nil, fmt.Errorf("failed to load keypair: %w", err)
+	}
+
+	client := &http.Client{
+		Transport: &http.Transport{
+			TLSClientConfig: &tls.Config{
+				RootCAs:      pool,
+				Certificates: []tls.Certificate{cert},
+			},
+		},
+	}
+
+	return client, nil
+}
+
+func getCurrentState(client *http.Client, logger *log.Logger) string {
+	resp, err := client.Post("https://example.net:3001/register", "application/json", nil)
+	if err != nil {
+		logger.Fatalf("registration failed: %v", err)
+	}
+
+	if resp.StatusCode > 399 {
+		logger.Printf("ERROR: getCurrentState: failed to get status [%d]", resp.StatusCode)
+		return ""
+	}
+
+	out := map[string]string{}
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		log.Printf("ERROR: getCurrentState: parsing response body: %v", err)
+		return ""
+	}
+
+	err = json.Unmarshal(body, &out)
+	if err != nil {
+		log.Printf("ERROR: getCurrentState: failed to unmarshal response: %s '%s'", err, body)
+		return ""
+	}
+
+	switch resp.StatusCode {
+	case http.StatusCreated:
+		logger.Printf("successfully started application registration")
+		return "pending_approval"
+	case http.StatusOK:
+		return out["status"]
+	default:
+		return ""
+	}
+}