Make transactions block when using WithReconnect

When creating a client using WithReconnect any requested Transact method
will block if the client is currently disconnected, and wait until it is
reconnected to execute the transaction (within a given context).

Signed-off-by: Tim Rozet <trozet@redhat.com>

client/client.go

@@ -675,10 +675,31 @@ func (o *ovsdbClient) listDbs(ctx context.Context) ([]string, error) {
 // RFC 7047 : transact
 func (o *ovsdbClient) Transact(ctx context.Context, operation ...ovsdb.Operation) ([]ovsdb.OperationResult, error) {
 	o.rpcMutex.Lock()
-	defer o.rpcMutex.Unlock()
 	if o.rpcClient == nil {
-		return nil, ErrNotConnected
+		o.rpcMutex.Unlock()
+		if o.options.reconnect {
+			o.logger.V(5).Info("blocking transaction until reconnected", "operations",
+				fmt.Sprintf("%+v", operation))
+			ticker := time.NewTicker(50 * time.Millisecond)
+			defer ticker.Stop()
+			for {
+				select {
+				case <-ctx.Done():
+					return nil, fmt.Errorf("%w: while awaiting reconnection", ctx.Err())
+				case <-ticker.C:
+					o.rpcMutex.Lock()
+					if o.rpcClient != nil {
+						break
+					}
+					o.rpcMutex.Unlock()
+				}
+			}
+		} else {
+			return nil, ErrNotConnected
+		}
 	}
+	defer o.rpcMutex.Unlock()
+
 	return o.transact(ctx, o.primaryDBName, operation...)
 }
 

client/options.go

@@ -97,7 +97,9 @@ func WithLeaderOnly(leaderOnly bool) Option {
 // WithReconnect tells the client to automatically reconnect when
 // disconnected. The timeout is used to construct the context on
 // each call to Connect, while backoff dictates the backoff
-// algorithm to use
+// algorithm to use. Using WithReconnect implies that
+// requested transactions will block until the client has fully reconnected,
+// rather than immediately returning an error if there is no connection.
 func WithReconnect(timeout time.Duration, backoff backoff.BackOff) Option {
 	return func(o *options) error {
 		o.reconnect = true