ce7cb702218693d08ea6d83464d2457c9250027c

services/oci-l4-relay-wan-controller/recovery.go

@@ -0,0 +1,52 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"time"
+)
+
+func waitForWireGuard(ctx context.Context, endpoint string, timeout time.Duration) error {
+	ctx, cancel := context.WithTimeout(ctx, timeout)
+	defer cancel()
+	transport := &http.Transport{}
+	defer transport.CloseIdleConnections()
+	client := &http.Client{
+		Transport: transport,
+		Timeout:   5 * time.Second,
+		CheckRedirect: func(_ *http.Request, _ []*http.Request) error {
+			return http.ErrUseLastResponse
+		},
+	}
+	ticker := time.NewTicker(2 * time.Second)
+	defer ticker.Stop()
+	for {
+		if err := probeWireGuard(ctx, client, endpoint); err == nil {
+			return nil
+		} else {
+			select {
+			case <-ctx.Done():
+				return fmt.Errorf("%w: %v", ctx.Err(), err)
+			case <-ticker.C:
+			}
+		}
+	}
+}
+
+func probeWireGuard(ctx context.Context, client *http.Client, endpoint string) error {
+	request, err := http.NewRequestWithContext(ctx, http.MethodGet, endpoint, nil)
+	if err != nil {
+		return err
+	}
+	response, err := client.Do(request)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = response.Body.Close() }()
+	// The relay proxy fetches this response live from the OCI WireGuard address.
+	if response.StatusCode != http.StatusOK {
+		return fmt.Errorf("WireGuard endpoint returned HTTP %d", response.StatusCode)
+	}
+	return nil
+}