package peerstream import ( "context" "errors" "fmt" "time" "github.com/hashicorp/go-memdb" "github.com/hashicorp/consul/agent/cache" "github.com/hashicorp/consul/agent/structs" "github.com/hashicorp/consul/lib/retry" "github.com/hashicorp/consul/proto/pbservice" ) // This file contains direct state store functions that need additional // management to have them emit events. Ideally these would go through // streaming machinery instead to be cheaper. func (m *subscriptionManager) notifyExportedServicesForPeerID(ctx context.Context, state *subscriptionState, peerID string) { // Wait until this is subscribed-to. select { case <-m.serviceSubReady: case <-ctx.Done(): return } // syncSubscriptionsAndBlock ensures that the subscriptions to the subscription backend // match the list of services exported to the peer. m.syncViaBlockingQuery(ctx, "exported-services", func(ctx context.Context, store StateStore, ws memdb.WatchSet) (interface{}, error) { // Get exported services for peer id _, list, err := store.ExportedServicesForPeer(ws, peerID, m.config.Datacenter) if err != nil { return nil, fmt.Errorf("failed to watch exported services for peer %q: %w", peerID, err) } return list, nil }, subExportedServiceList, state.updateCh) } // TODO: add a new streaming subscription type to list-by-kind-and-partition since we're getting evictions func (m *subscriptionManager) notifyMeshGatewaysForPartition(ctx context.Context, state *subscriptionState, partition string) { // Wait until this is subscribed-to. select { case <-m.serviceSubReady: case <-ctx.Done(): return } m.syncViaBlockingQuery(ctx, "mesh-gateways", func(ctx context.Context, store StateStore, ws memdb.WatchSet) (interface{}, error) { // Fetch our current list of all mesh gateways. entMeta := structs.DefaultEnterpriseMetaInPartition(partition) idx, nodes, err := store.ServiceDump(ws, structs.ServiceKindMeshGateway, true, entMeta, structs.DefaultPeerKeyword) if err != nil { return nil, fmt.Errorf("failed to watch mesh gateways services for partition %q: %w", partition, err) } if idx == 0 { idx = 1 } // convert back to a protobuf flavor result := &pbservice.IndexedCheckServiceNodes{ Index: idx, Nodes: make([]*pbservice.CheckServiceNode, len(nodes)), } for i, csn := range nodes { result.Nodes[i] = pbservice.NewCheckServiceNodeFromStructs(&csn) } return result, nil }, subMeshGateway+partition, state.updateCh) } func (m *subscriptionManager) syncViaBlockingQuery( ctx context.Context, queryType string, queryFn func(ctx context.Context, store StateStore, ws memdb.WatchSet) (interface{}, error), correlationID string, updateCh chan<- cache.UpdateEvent, ) { waiter := &retry.Waiter{ MinFailures: 1, Factor: 500 * time.Millisecond, MaxWait: 60 * time.Second, Jitter: retry.NewJitter(100), } logger := m.logger if queryType != "" { logger = m.logger.With("queryType", queryType) } store := m.getStore() for ctx.Err() == nil { ws := memdb.NewWatchSet() ws.Add(store.AbandonCh()) ws.Add(ctx.Done()) if result, err := queryFn(ctx, store, ws); err != nil { // Return immediately if the context was cancelled. if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) { return } logger.Error("failed to sync from query", "error", err) waiter.Wait(ctx) } else { select { case <-ctx.Done(): return case updateCh <- cache.UpdateEvent{CorrelationID: correlationID, Result: result}: waiter.Reset() } // Block for any changes to the state store. ws.WatchCtx(ctx) } } }