[SREP-1559] feat: check that when used, proxy url starts with http and do proxy hostname dns lookup to confirm connectivity

pkg/cli/config/config.go

@@ -3,6 +3,7 @@ package config
 import (
 	"context"
 	"fmt"
+	"net"
 	"net/http"
 	"net/url"
 	"os"
@@ -222,6 +223,8 @@ func GetBackplaneConfiguration() (bpConfig BackplaneConfiguration, err error) {
 	return bpConfig, nil
 }
 
+var lookupHost = net.LookupHost
+
 var testProxy = func(ctx context.Context, testURL string, proxyURL url.URL) error {
 	// Try call the test URL via the proxy
 	client := &http.Client{
@@ -410,6 +413,15 @@ func (config *BackplaneConfiguration) testHTTPRequestToBackplaneAPI() (bool, err
 		if err != nil {
 			return false, err
 		}
+		scheme := proxyURL.Scheme
+		if scheme != "http" && scheme != "https" {
+			return false, fmt.Errorf("proxy URL scheme must be http or https, got: %s", scheme)
+		}
+		hostname := proxyURL.Hostname()
+		_, err = lookupHost(hostname)
+		if err != nil {
+			return false, fmt.Errorf("DNS lookup failed for proxy hostname '%s': %v (check network connectivity or VPN if required)", hostname, err)
+		}		
 		http.DefaultTransport = &http.Transport{Proxy: http.ProxyURL(proxyURL)}
 	}
 

pkg/cli/config/config_test.go

@@ -7,6 +7,7 @@ import (
 	"net/http/httptest"
 	"net/url"
 	"os"
+	"strings"
 	"testing"
 
 	"github.com/spf13/viper"
@@ -85,6 +86,89 @@ func TestGetBackplaneConnection(t *testing.T) {
 			t.Failed()
 		}
 	})
+
+	t.Run("should pass for valid http proxy URL", func(t *testing.T) {
+		proxyURL := "http://www.example.com"
+		config := BackplaneConfiguration{URL: "https://api.example.com", ProxyURL: &proxyURL}
+		_, err := config.testHTTPRequestToBackplaneAPI()
+
+		// Should not get scheme validation error (DNS lookup error is expected)
+		if err != nil && strings.Contains(err.Error(), "proxy URL scheme must be http or https") {
+			t.Errorf("unexpected scheme validation error: %v", err)
+		}
+	})
+
+	t.Run("should pass for valid https proxy URL", func(t *testing.T) {
+		proxyURL := "https://www.example.com"
+		config := BackplaneConfiguration{URL: "https://api.example.com", ProxyURL: &proxyURL}
+		_, err := config.testHTTPRequestToBackplaneAPI()
+
+		// Should not get scheme validation error (DNS lookup error is expected)
+		if err != nil && strings.Contains(err.Error(), "proxy URL scheme must be http or https") {
+			t.Errorf("unexpected scheme validation error: %v", err)
+		}
+	})
+
+	t.Run("should fail for proxy URL without scheme", func(t *testing.T) {
+		proxyURL := "www.example.com"
+		config := BackplaneConfiguration{URL: "https://api.example.com", ProxyURL: &proxyURL}
+		_, err := config.testHTTPRequestToBackplaneAPI()
+
+		if err == nil {
+			t.Errorf("expected error but got none")
+		} else if !strings.Contains(err.Error(), "proxy URL scheme must be http or https, got:") {
+			t.Errorf("expected scheme validation error, got: %s", err.Error())
+		}
+	})
+
+	t.Run("should fail for ftp proxy URL", func(t *testing.T) {
+		proxyURL := "ftp://www.example.com"
+		config := BackplaneConfiguration{URL: "https://api.example.com", ProxyURL: &proxyURL}
+		_, err := config.testHTTPRequestToBackplaneAPI()
+
+		if err == nil {
+			t.Errorf("expected error but got none")
+		} else if !strings.Contains(err.Error(), "proxy URL scheme must be http or https, got: ftp") {
+			t.Errorf("expected scheme validation error for ftp, got: %s", err.Error())
+		}
+	})
+
+	t.Run("should fail on DNS lookup error", func(t *testing.T) {
+		// Mock DNS lookup to return an error
+		originalLookupHost := lookupHost
+		lookupHost = func(hostname string) ([]string, error) {
+			return nil, fmt.Errorf("DNS resolution failed")
+		}
+		defer func() { lookupHost = originalLookupHost }()
+
+		proxyURL := "https://proxy.example.com"
+		config := BackplaneConfiguration{URL: "https://api.example.com", ProxyURL: &proxyURL}
+		_, err := config.testHTTPRequestToBackplaneAPI()
+
+		if err == nil {
+			t.Errorf("expected DNS lookup error but got none")
+		} else if !strings.Contains(err.Error(), "DNS lookup failed for proxy hostname") {
+			t.Errorf("expected DNS lookup error, got: %s", err.Error())
+		}
+	})
+
+	t.Run("should pass on successful DNS lookup", func(t *testing.T) {
+		// Mock DNS lookup to succeed
+		originalLookupHost := lookupHost
+		lookupHost = func(hostname string) ([]string, error) {
+			return []string{"192.168.1.1"}, nil
+		}
+		defer func() { lookupHost = originalLookupHost }()
+
+		proxyURL := "https://proxy.example.com"
+		config := BackplaneConfiguration{URL: "https://api.example.com", ProxyURL: &proxyURL}
+		_, err := config.testHTTPRequestToBackplaneAPI()
+
+		// Should not get DNS lookup error (HTTP request error is expected)
+		if err != nil && strings.Contains(err.Error(), "DNS lookup failed for proxy hostname") {
+			t.Errorf("unexpected DNS lookup error: %v", err)
+		}
+	})
 }
 
 func TestBackplaneConfiguration_getFirstWorkingProxyURL(t *testing.T) {