go/runtime/registry/host: Remove obsolete RONL versions from aggregate

go/runtime/host/multi/multi.go

@@ -7,6 +7,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"slices"
 	"sync"
 
 	"github.com/cenkalti/backoff/v4"
@@ -343,13 +344,27 @@ func (agg *Aggregate) Component(id component.ID) (host.Runtime, bool) {
 	return nil, false
 }
 
-// GetVersion retrieves the runtime host for the specified version.
-func (agg *Aggregate) GetVersion(version version.Version) (host.Runtime, error) {
+// Versions returns a sorted list of all versions in the aggregate.
+func (agg *Aggregate) Versions() []version.Version {
 	agg.l.RLock()
 	defer agg.l.RUnlock()
 
-	host := agg.hosts[version]
-	if host == nil {
+	versions := make([]version.Version, 0, len(agg.hosts))
+	for v := range agg.hosts {
+		versions = append(versions, v)
+	}
+
+	slices.SortFunc(versions, version.Version.Cmp)
+	return versions
+}
+
+// Version retrieves the runtime host for the specified version.
+func (agg *Aggregate) Version(version version.Version) (host.Runtime, error) {
+	agg.l.RLock()
+	defer agg.l.RUnlock()
+
+	host, ok := agg.hosts[version]
+	if !ok {
 		return nil, ErrNoSuchVersion
 	}
 	// Only allow fetching either the active or next versions.
@@ -379,9 +394,7 @@ func (agg *Aggregate) AddVersion(version version.Version, rt host.Runtime) error
 	agg.l.Lock()
 	defer agg.l.Unlock()
 
-	agg.logger.Info("adding version",
-		"version", version,
-	)
+	agg.logger.Info("adding version", "version", version)
 
 	if id := rt.ID(); id != agg.id {
 		return fmt.Errorf("runtime/host/multi: runtime mismatch: got '%s', expected '%s'", id, agg.id)
@@ -393,9 +406,7 @@ func (agg *Aggregate) AddVersion(version version.Version, rt host.Runtime) error
 
 	agg.hosts[version] = newAggregateHost(rt, version)
 
-	agg.logger.Info("version added",
-		"version", version,
-	)
+	agg.logger.Info("version added", "version", version)
 
 	if agg.running {
 		agg.startActiveLocked()
@@ -405,6 +416,32 @@ func (agg *Aggregate) AddVersion(version version.Version, rt host.Runtime) error
 	return nil
 }
 
+// RemoveVersion removes the specified version from the aggregate.
+//
+// A version cannot be removed if it is currently running, meaning it
+// is marked as the active version or the next version.
+func (agg *Aggregate) RemoveVersion(version version.Version) error {
+	agg.l.Lock()
+	defer agg.l.Unlock()
+
+	agg.logger.Info("removing version", "version", version)
+
+	if _, ok := agg.hosts[version]; !ok {
+		return ErrNoSuchVersion
+	}
+	if agg.activeVersion != nil && version == *agg.activeVersion {
+		return fmt.Errorf("runtime/host/multi: cannot remove active version '%s'", version)
+	}
+	if agg.nextVersion != nil && version == *agg.nextVersion {
+		return fmt.Errorf("runtime/host/multi: cannot remove next version '%s'", version)
+	}
+	delete(agg.hosts, version)
+
+	agg.logger.Info("version removed", "version", version)
+
+	return nil
+}
+
 // SetVersion updates the active and next runtime versions.
 //
 // If the aggregate is not running, this function simply updates the versions.

go/runtime/registry/host.go

@@ -11,6 +11,7 @@ import (
 	"github.com/oasisprotocol/oasis-core/go/runtime/bundle/component"
 	"github.com/oasisprotocol/oasis-core/go/runtime/host"
 	"github.com/oasisprotocol/oasis-core/go/runtime/host/composite"
+	"github.com/oasisprotocol/oasis-core/go/runtime/host/multi"
 	"github.com/oasisprotocol/oasis-core/go/runtime/host/protocol"
 )
 
@@ -126,7 +127,7 @@ func (n *RuntimeHostNode) GetHostedRuntimeCapabilityTEEForVersion(version versio
 	if !ok {
 		return nil, fmt.Errorf("failed to get RONL component runtime host")
 	}
-	rt, err := comp.GetVersion(version)
+	rt, err := comp.Version(version)
 	if err != nil {
 		return nil, err
 	}
@@ -138,22 +139,37 @@ func (n *RuntimeHostNode) SetHostedRuntimeVersion(active *version.Version, next
 	n.mu.Lock()
 	defer n.mu.Unlock()
 
+	pruneVersions := func(comp *multi.Aggregate, lowest version.Version) {
+		for _, v := range comp.Versions() {
+			if !v.Less(lowest) {
+				return
+			}
+			_ = comp.RemoveVersion(v)
+		}
+	}
+
 	for id, comp := range n.host.Components() {
-		latest, ok := n.rofls[id]
-		if !ok {
+		switch latest, ok := n.rofls[id]; ok {
+		case false:
+			// RONL components should honor versioning.
 			comp.SetVersion(active, next)
-			continue
-		}
 
-		// ROFL components should start when the RONL component starts and
-		// should upgrade immediately when a new version becomes available.
-		switch {
-		case active == nil && next == nil:
-			comp.SetVersion(nil, nil)
-		case active == nil && next != nil:
-			comp.SetVersion(nil, &latest)
-		default:
-			comp.SetVersion(&latest, nil)
+			if active != nil {
+				pruneVersions(comp, *active)
+			}
+		case true:
+			// ROFL components should start when the RONL component starts and
+			// should upgrade immediately when a new version becomes available.
+			switch {
+			case active == nil && next == nil:
+				comp.SetVersion(nil, nil)
+			case active == nil && next != nil:
+				comp.SetVersion(nil, &latest)
+			default:
+				comp.SetVersion(&latest, nil)
+			}
+
+			pruneVersions(comp, latest)
 		}
 	}
 }