Refactor itopo initialization (#3661)

Most of the initializers used default values. Changing to
a config struct makes the itopo package easier to refactor.

acceptance/topo_sd_reload/testdata/topology_reload.json

@@ -73,7 +73,6 @@
     }
   },
   "ColibriService": {},
-  "DiscoveryService": {},
   "Attributes": [
     "authoritative",
     "core",

go/border/brconf/conf.go

@@ -83,7 +83,7 @@ func (cfg *BRConf) loadTopo(id string) error {
 	return nil
 }
 
-// initTopo initializesthe entries related to topo in the config.
+// initTopo initializes the entries related to topo in the config.
 func (cfg *BRConf) initTopo(id string, topo topology.Topology) error {
 	cfg.Topo = topo
 	cfg.IA = cfg.Topo.IA()

go/border/setup.go

@@ -69,10 +69,16 @@ func (r *Router) setup() error {
 		return err
 	}
 	// Initialize itopo.
-	itopo.Init(r.Id, proto.ServiceType_br, itopo.Callbacks{})
-	if _, _, err := itopo.SetStatic(conf.Topo); err != nil {
+	itopo.Init(
+		&itopo.Config{
+			ID:  r.Id,
+			Svc: proto.ServiceType_br,
+		},
+	)
+	if err := itopo.Update(conf.Topo); err != nil {
 		return err
 	}
+	conf.Topo = itopo.Get()
 	// Setup new context.
 	if err = r.setupCtxFromConfig(conf); err != nil {
 		return err
@@ -120,13 +126,13 @@ func (r *Router) setupCtxFromConfig(config *brconf.BRConf) error {
 	// We want to keep in sync itopo and the context that is set.
 	// We attempt to set the context with the topology that will be current
 	// after setting itopo. If setting itopo fails in the end, we rollback the context.
-	tx, err := itopo.BeginSetStatic(config.Topo.Writable())
+	tx, err := itopo.BeginUpdate(config.Topo.Writable())
 	if err != nil {
 		return err
 	}
 	// Set config to use the appropriate topology. The returned topology is
 	// not necessarily the same as config.Topo. It can be another static topology.
-	newConf, err := brconf.WithNewTopo(r.Id, topology.FromRWTopology(tx.Get()), config)
+	newConf, err := brconf.WithNewTopo(r.Id, tx.Get(), config)
 	if err != nil {
 		return err
 	}
@@ -138,7 +144,7 @@ func (r *Router) setupCtxFromConfig(config *brconf.BRConf) error {
 func (r *Router) setupCtxFromStatic(topo *topology.RWTopology) (bool, error) {
 	r.setCtxMtx.Lock()
 	defer r.setCtxMtx.Unlock()
-	tx, err := itopo.BeginSetStatic(topo)
+	tx, err := itopo.BeginUpdate(topo)
 	return r.setupCtxFromTopoUpdate(tx, err)
 }
 
@@ -151,7 +157,7 @@ func (r *Router) setupCtxFromTopoUpdate(tx itopo.Transaction, err error) (bool,
 		return false, nil
 	}
 	log.Trace("====> Setting up new context from topology update")
-	newConf, err := brconf.WithNewTopo(r.Id, topology.FromRWTopology(tx.Get()), rctx.Get().Conf)
+	newConf, err := brconf.WithNewTopo(r.Id, tx.Get(), rctx.Get().Conf)
 	if err != nil {
 		return false, err
 	}

go/cs/main.go

@@ -715,13 +715,18 @@ func setup() error {
 	if err := cfg.Validate(); err != nil {
 		return common.NewBasicError("Unable to validate config", err)
 	}
-	clbks := itopo.Callbacks{UpdateStatic: handleTopoUpdate}
-	// Use CS for monolith for now
-	itopo.Init(cfg.General.ID, proto.ServiceType_cs, clbks)
 	topo, err := topology.FromJSONFile(cfg.General.Topology)
 	if err != nil {
 		return common.NewBasicError("Unable to load topology", err)
 	}
+	// Use CS for monolith for now
+	itopo.Init(
+		&itopo.Config{
+			ID:        cfg.General.ID,
+			Svc:       proto.ServiceType_cs,
+			Callbacks: itopo.Callbacks{OnUpdate: handleTopoUpdate},
+		},
+	)
 	return initTopo(topo)
 }
 
@@ -733,7 +738,7 @@ func handleTopoUpdate() {
 }
 
 func initTopo(topo topology.Topology) error {
-	if _, _, err := itopo.SetStatic(topo); err != nil {
+	if err := itopo.Update(topo); err != nil {
 		return serrors.WrapStr("Unable to set initial static topology", err)
 	}
 	infraenv.InitInfraEnvironment(cfg.General.Topology)

go/lib/env/env.go

@@ -201,7 +201,7 @@ func ReloadTopology(topologyPath string) {
 		log.Error("Unable to reload topology", "err", err)
 		return
 	}
-	if _, _, err := itopo.SetStatic(topo); err != nil {
+	if err := itopo.Update(topo); err != nil {
 		log.Error("Unable to set topology", "err", err)
 		return
 	}

go/lib/infra/modules/itopo/doc.go

@@ -12,126 +12,20 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-/*
-Package itopo stores the static and dynamic topology. Client packages
-that grab a reference with Get are guaranteed to receive a stable
-snapshot of the topology. The returned value is the topology that is
-currently active.
-
-There are two types of topologies, the static and the dynamic topology.
-For more information see lib/discovery.
-
-Initialization
-
-The package must be initialized with Init. In subsequent updates through
-SetStatic or SetDynamic, the new topology is checked whether it is
-compatible with the previous version. The rules differ between services.
-
-If the dynamic topology is set, the initializing client should start
-the periodic cleaner to evict expired dynamic topologies.
-
-Updates
-
-The update of the topology is only valid if a set of constraints is
-met. The constraints differ between dynamic and static topology, and
-also between the initialized service type.
-
-In a static topology update, when the diff is empty, the static
-topology is only updated if it expires later than the current static.
-Otherwise, SetStatic succeeds and indicates that the in-memory copy
-has not been updated.
-
-A static topology update can force the dynamic topology to be dropped,
-if it does no longer meet the constraints.
-
-Constraints
-
-The topology is split into five parts. An update is valid under the
-constraints, if the constraints for each part are met.
-
-Immutable:
-This part may not differ from the initial static topology.
-
-Mutable:
-This part may differ from the initial static topology. It may also
-differ between the currently active static and dynamic topology.
-
-Semi-Mutable:
-This part may differ between static topology versions. However, it
-may not differ between the current dynamic and static topology.
-If an update to the static topology modifies this part, the dynamic
-topology is dropped.
-
-Time:
-This part is ignored when validating the constraints. It is used
-to determine if a topology shall be updated if there are no
-differences in the other parts.
-
-Ignored:
-This part is always ignored.
-
-Default Topology Split
-
-The topology file for default initialization (calling Init) is split
-into immutable, mutable, time and ignored.
-
- ISD_AS                Immutable
- Core                  Immutable
- Overlay               Immutable
- MTU                   Immutable
-
- Service Entries       Mutable
- BorderRouter Entries  Mutable
-
- Timestamp             Time
- TTL                   Time
-
- TimestampHuman        Ignored
-
-Service Topology Split
-
-The topology file for services is split into immutable, mutable,
-time and ignored.
-
- ISD_AS                Immutable
- Core                  Immutable
- Overlay               Immutable
- MTU                   Immutable
- OwnSvcType[OwnID]     Immutable // The service entry for the initialized element.
-
- Service Entries       Mutable   // Except OwnSvcType[OwnID].
- BorderRouter Entries  Mutable
-
- Timestamp             Time
- TTL                   Time
-
- TimestampHuman        Ignored
-
-Border Router Topology Split
-
-The topology file for border routers is split into immutable,
-semi-mutable, mutable, time and ignored.
-
- ISD_AS                              Immutable
- Core                                Immutable
- Overlay                             Immutable
- MTU                                 Immutable
- BorderRouters[OwnId][InternalAddrs] Immutable    // Internal address of initialized router.
- BorderRouters[OwnId][CtrlAddr]      Immutable    // Control address of initialized router.
-
- BorderRouters[OwnId][Interfaces]    Semi-Mutable // Interfaces of initialized router.
-
- Service Entries       Mutable
- BorderRouter Entries  Mutable                    // Except BorderRouters[OwnId].
-
- Timestamp             Time
- TTL                   Time
-
- TimestampHuman        Ignored
-
-Callbacks
-
-The client package can register callbacks to be notified about
-certain events.
-*/
+// Package itopo stores topology state and manages topology updates for an application.
+//
+// The package must be initialized with Init. In subsequent updates through Update, the new
+// topology is checked whether it is compatible with the previous version. The rules differ between
+// services.
+//
+// Updates
+//
+// The update of the topology is only valid if a set of constraints is met. The constraints differ
+// between the initialized service types.
+//
+// In a topology update, when the diff is empty, the topology is only updated if it
+// expires later than the current topology. Otherwise, Update succeeds and indicates that the
+// in-memory copy has not been updated.
+//
+// The client package can register callbacks to be notified about certain events.
 package itopo