xds: remove Server.Initialize

Requiring a call to initialize to set a single field is not really substantially different
from having to set that field to a value.

agent/agent.go

@@ -655,8 +655,8 @@ func (a *Agent) listenAndServeGRPC() error {
 		ResolveToken:       a.resolveToken,
 		CheckFetcher:       a,
 		CfgFetcher:         a,
+		AuthCheckFrequency: xds.DefaultAuthCheckFrequency,
 	}
-	xdsServer.Initialize()
 
 	var err error
 	if a.config.HTTPSPort > 0 {

agent/xds/server.go

@@ -125,13 +125,6 @@ type Server struct {
 	CfgFetcher         ConfigFetcher
 }
 
-// Initialize will finish configuring the Server for first use.
-func (s *Server) Initialize() {
-	if s.AuthCheckFrequency == 0 {
-		s.AuthCheckFrequency = DefaultAuthCheckFrequency
-	}
-}
-
 // StreamAggregatedResources implements
 // envoydisco.AggregatedDiscoveryServiceServer. This is the ADS endpoint which is
 // the only xDS API we directly support for now.

agent/xds/server_test.go

@@ -102,7 +102,6 @@ func TestServer_StreamAggregatedResources_BasicProtocol(t *testing.T) {
 		CfgMgr:       mgr,
 		ResolveToken: aclResolve,
 	}
-	s.Initialize()
 
 	sid := structs.NewServiceID("web-sidecar-proxy", nil)
 
@@ -454,7 +453,6 @@ func TestServer_StreamAggregatedResources_ACLEnforcement(t *testing.T) {
 				CfgMgr:       mgr,
 				ResolveToken: aclResolve,
 			}
-			s.Initialize()
 
 			errCh := make(chan error, 1)
 			go func() {
@@ -528,7 +526,6 @@ func TestServer_StreamAggregatedResources_ACLTokenDeleted_StreamTerminatedDuring
 		ResolveToken:       aclResolve,
 		AuthCheckFrequency: 1 * time.Hour, // make sure this doesn't kick in
 	}
-	s.Initialize()
 
 	errCh := make(chan error, 1)
 	go func() {
@@ -622,7 +619,6 @@ func TestServer_StreamAggregatedResources_ACLTokenDeleted_StreamTerminatedInBack
 		ResolveToken:       aclResolve,
 		AuthCheckFrequency: 100 * time.Millisecond, // Make this short.
 	}
-	s.Initialize()
 
 	errCh := make(chan error, 1)
 	go func() {
@@ -707,7 +703,6 @@ func TestServer_StreamAggregatedResources_IngressEmptyResponse(t *testing.T) {
 		CfgMgr:       mgr,
 		ResolveToken: aclResolve,
 	}
-	s.Initialize()
 
 	sid := structs.NewServiceID("ingress-gateway", nil)