feat: add retry flag

internal/app/app.go

@@ -1,6 +1,9 @@
 package app
 
 import (
+	"math/rand"
+	"time"
+
 	"github.com/miekg/dns"
 	"github.com/mr-karan/doggo/pkg/models"
 	"github.com/mr-karan/doggo/pkg/resolvers"
@@ -33,3 +36,20 @@ func New(logger *logf.Logger, buildVersion string) App {
 	}
 	return app
 }
+
+// Attempts a DNS Lookup with retries for a given Question.
+func (app *App) LookupWithRetry(attempts int, resolver resolvers.Resolver, ques dns.Question) (resolvers.Response, error) {
+	resp, err := resolver.Lookup(ques)
+	if err != nil {
+		// Retry lookup.
+		attempts--
+		if attempts > 0 {
+			// Add some random delay.
+			time.Sleep(time.Millisecond*300 + (time.Duration(rand.Int63n(int64(time.Millisecond*100))))/2)
+			app.Logger.Debug("retrying lookup")
+			return app.LookupWithRetry(attempts, resolver, ques)
+		}
+		return resolvers.Response{}, err
+	}
+	return resp, nil
+}