Avoid nil pointer exception when Ingress has no Backends (#578)

Author: Delyan Raychev

pkg/appgw/certificates.go

@@ -38,7 +38,7 @@ func (c *appGwConfigBuilder) getSslCertificates(cbCtx *ConfigBuilderContext) *[]
 		sslCertificates = append(sslCertificates, c.newCert(secretID, cert))
 	}
 
-	if cbCtx.EnvVariables.EnableBrownfieldDeployment {
+	if cbCtx.EnvVariables.EnableBrownfieldDeployment && c.appGw.SslCertificates != nil {
 		// MergePools would produce unique list of pools based on Name. Blacklisted pools, which have the same name
 		// as a managed pool would be overwritten.
 		sslCertificates = brownfield.MergeCerts(*c.appGw.SslCertificates, sslCertificates)

pkg/appgw/validators.go

@@ -50,6 +50,9 @@ func validateServiceDefinition(eventRecorder record.EventRecorder, config *n.App
 				continue
 			}
 			for pathIdx := range rule.HTTP.Paths {
+				if ingress.Spec.Backend == nil {
+					continue
+				}
 				path := &rule.HTTP.Paths[pathIdx]
 				backendIDs[generateBackendID(ingress, rule, path, &path.Backend)] = nil
 			}