[RFC] client: honor last transaction IDs

cache/cache.go

@@ -17,6 +17,7 @@ import (
 	"github.com/ovn-org/libovsdb/mapper"
 	"github.com/ovn-org/libovsdb/model"
 	"github.com/ovn-org/libovsdb/ovsdb"
+	"github.com/ovn-org/libovsdb/util"
 )
 
 const (
@@ -718,6 +719,42 @@ func (t *TableCache) Purge(dbModel model.DatabaseModel) {
 	}
 }
 
+// PurgeTable drops all data in the given table's cache and reinitializes it using the
+// provided database model
+func (t *TableCache) PurgeTable(dbModel model.DatabaseModel, name string) error {
+	return t.PurgeTableRows(dbModel, name, nil)
+}
+
+// PurgeTableRows drops all rows in the given table's cache that match the given conditions
+func (t *TableCache) PurgeTableRows(dbModel model.DatabaseModel, name string, conditions []ovsdb.Condition) error {
+	t.mutex.Lock()
+	defer t.mutex.Unlock()
+	t.dbModel = dbModel
+	tableTypes := t.dbModel.Types()
+	dataType, ok := tableTypes[name]
+	if !ok {
+		return fmt.Errorf("table %s not found", name)
+	}
+	if len(conditions) == 0 {
+		t.cache[name] = newRowCache(name, t.dbModel, dataType)
+		return nil
+	}
+
+	r := t.cache[name]
+	rows, err := r.RowsByCondition(conditions)
+	if err != nil {
+		return err
+	}
+	delErrors := []error{}
+	for uuid := range rows {
+		if err := r.Delete(uuid); err != nil {
+			delErrors = append(delErrors, fmt.Errorf("failed to delete %s: %w", uuid, err))
+		}
+	}
+
+	return util.CombineErrors(delErrors, "failed to delete rows")
+}
+
 // AddEventHandler registers the supplied EventHandler to receive cache events
 func (t *TableCache) AddEventHandler(handler EventHandler) {
 	t.eventProcessor.AddEventHandler(handler)

client/client.go

@@ -24,6 +24,7 @@ import (
 	"github.com/ovn-org/libovsdb/model"
 	"github.com/ovn-org/libovsdb/ovsdb"
 	"github.com/ovn-org/libovsdb/ovsdb/serverdb"
+	"github.com/ovn-org/libovsdb/util"
 )
 
 // Constants defined for libovsdb
@@ -260,15 +261,7 @@ func (o *ovsdbClient) connect(ctx context.Context, reconnect bool) error {
 	}
 
 	if !connected {
-		if len(connectErrors) == 1 {
-			return connectErrors[0]
-		}
-		var combined []string
-		for _, e := range connectErrors {
-			combined = append(combined, e.Error())
-		}
-
-		return fmt.Errorf("unable to connect to any endpoints: %s", strings.Join(combined, ". "))
+		return util.CombineErrors(connectErrors, "unable to connect to any endpoints")
 	}
 
 	// if we're reconnecting, re-start all the monitors
@@ -371,8 +364,6 @@ func (o *ovsdbClient) tryEndpoint(ctx context.Context, u *url.URL) (string, erro
 				return "", err
 			}
 			db.api = newAPI(db.cache, o.logger)
-		} else {
-			db.cache.Purge(db.model)
 		}
 		db.cacheMutex.Unlock()
 	}
@@ -809,6 +800,51 @@ func (o *ovsdbClient) Monitor(ctx context.Context, monitor *Monitor) (MonitorCoo
 	return cookie, o.monitor(ctx, cookie, false, monitor)
 }
 
+func (db *database) getMonitorTableConditions(tm TableMonitor) (*ovsdb.Condition, error) {
+	model, err := db.model.NewModel(tm.Table)
+	if err != nil {
+		return nil, err
+	}
+	info, err := db.model.NewModelInfo(model)
+	if err != nil {
+		return nil, err
+	}
+	return db.model.Mapper.NewCondition(info, tm.Condition.Field, tm.Condition.Function, tm.Condition.Value)
+}
+
+// purge removes all rows from the row cache that match the monitor
+func (o *ovsdbClient) purge(db *database, monitor *Monitor) {
+	if len(monitor.Tables) == 0 {
+		db.cache.Purge(db.model)
+		return
+	}
+
+	var err error
+	for _, tm := range monitor.Tables {
+		if monitor.Method == ovsdb.ConditionalMonitorSinceRPC {
+			var cond *ovsdb.Condition
+			cond, err = db.getMonitorTableConditions(tm)
+			if err != nil {
+				break
+			}
+			err = db.cache.PurgeTableRows(db.model, tm.Table, []ovsdb.Condition{*cond})
+			if err != nil {
+				break
+			}
+		} else {
+			err = db.cache.PurgeTable(db.model, tm.Table)
+			if err != nil {
+				break
+			}
+		}
+	}
+
+	if err != nil {
+		o.logger.V(3).Error(err, "failed to purge database")
+		db.cache.Purge(db.model)
+	}
+}
+
 //gocyclo:ignore
 // monitor must only be called with a lock on monitorsMutex
 func (o *ovsdbClient) monitor(ctx context.Context, cookie MonitorCookie, reconnecting bool, monitor *Monitor) error {
@@ -859,12 +895,7 @@ func (o *ovsdbClient) monitor(ctx context.Context, cookie MonitorCookie, reconne
 
 	var args []interface{}
 	if monitor.Method == ovsdb.ConditionalMonitorSinceRPC {
-		// FIXME: We should pass the monitor.LastTransactionID here
-		// But that would require delaying clearing the cache until
-		// after the monitors have been re-established - the logic
-		// would also need to be different for monitor and monitor_cond
-		// as we must always clear the cache in that instance
-		args = ovsdb.NewMonitorCondSinceArgs(dbName, cookie, requests, emptyUUID)
+		args = ovsdb.NewMonitorCondSinceArgs(dbName, cookie, requests, monitor.LastTransactionID)
 	} else {
 		args = ovsdb.NewMonitorArgs(dbName, cookie, requests)
 	}
@@ -873,18 +904,24 @@ func (o *ovsdbClient) monitor(ctx context.Context, cookie MonitorCookie, reconne
 
 	switch monitor.Method {
 	case ovsdb.MonitorRPC:
+		o.purge(db, monitor)
 		var reply ovsdb.TableUpdates
 		err = o.rpcClient.CallWithContext(ctx, monitor.Method, args, &reply)
 		tableUpdates = reply
 	case ovsdb.ConditionalMonitorRPC:
+		o.purge(db, monitor)
 		var reply ovsdb.TableUpdates2
 		err = o.rpcClient.CallWithContext(ctx, monitor.Method, args, &reply)
 		tableUpdates = reply
 	case ovsdb.ConditionalMonitorSinceRPC:
 		var reply ovsdb.MonitorCondSinceReply
 		err = o.rpcClient.CallWithContext(ctx, monitor.Method, args, &reply)
-		if err == nil && reply.Found {
-			monitor.LastTransactionID = reply.LastTransactionID
+		if err == nil {
+			if reply.Found {
+				monitor.LastTransactionID = reply.LastTransactionID
+			} else {
+				o.purge(db, monitor)
+			}
 		}
 		tableUpdates = reply.Updates
 	default:

util/errors.go

@@ -0,0 +1,20 @@
+package util
+
+import (
+	"fmt"
+	"strings"
+)
+
+func CombineErrors(errors []error, msg string) error {
+	if len(errors) == 0 {
+		return nil
+	} else if len(errors) == 1 {
+		return errors[0]
+	}
+
+	var combined []string
+	for _, e := range errors {
+		combined = append(combined, e.Error())
+	}
+	return fmt.Errorf("%s: %s", msg, strings.Join(combined, ". "))
+}