.

go/neo/client/client.go

@@ -126,27 +126,28 @@ func (c *Client) talkMaster1(ctx context.Context) (err error) {
 	log.Info(ctx, "identification accepted")
 	Mlink := Mconn.Link()
 
+	wg, ctx := errgroup.WithContext(ctx)
+
+	// XXX + close Mconn
 	defer xio.CloseWhenDone(ctx, Mlink)()
 
-	// XXX .nodeTab.Reset()
+	// launch master notifications receiver
+	wg.Go(func() error {
+		return c.recvMaster(ctx, Mlink)
+	})
 
-	rpt := neo.AnswerPartitionTable{}
-	err = Mlink.Ask1(&neo.AskPartitionTable{}, &rpt)
-	if err != nil {
-		// XXX
-	}
+	// launch process that "drives" master (initiates & tx requests)
+	wg.Go(func() error {
+		return c.ctlMaster(ctx, Mlink)
+	}()
 
-	pt := neo.PartTabFromDump(rpt.PTid, rpt.RowList)
-	// XXX pt -> c.node.PartTab ?
-	_ = pt
+	return wg.Wait()
 
-	rlastTxn := neo.AnswerLastTransaction{}
-	err = Mlink.Ask1(&neo.LastTransaction{}, &rlastTxn)
-	if err != nil {
-		// XXX
-	}
+}
 
-	// XXX rlastTxn.Tid -> c.lastTid
+// recvMaster receives and handles notifications from master
+func (c *Client) recvMaster(ctx context.Context, Mlink *neo.NodeLink) error {
+	// XXX .nodeTab.Reset()
 
 	for {
 		req, err := Mlink.Recv1()
@@ -175,6 +176,35 @@ func (c *Client) talkMaster1(ctx context.Context) (err error) {
 	}
 }
 
+func (c *Client) ctlMaster(ctx context.Context, Mlink *neo.NodeLink) error {
+	// ask M for PT
+	rpt := neo.AnswerPartitionTable{}
+	err = Mlink.Ask1(&neo.AskPartitionTable{}, &rpt)
+	if err != nil {
+		return err
+	}
+
+	// XXX lock
+	pt := neo.PartTabFromDump(rpt.PTid, rpt.RowList)
+	// XXX pt -> c.node.PartTab ?
+	_ = pt
+
+	// ask M about last_tid
+	rlastTxn := neo.AnswerLastTransaction{}
+	err = Mlink.Ask1(&neo.LastTransaction{}, &rlastTxn)
+	if err != nil {
+		return err
+	}
+
+	// XXX lock
+	// XXX rlastTxn.Tid -> c.lastTid
+
+	// XXX what next?
+	return nil
+
+	// TODO transaction control? -> better in original goroutines doing the txn (just share Mlink)
+}
+
 // --- user API calls ---
 
 func (c *Client) LastTid(ctx context.Context) (zodb.Tid, error) {

go/neo/neo.go

@@ -74,7 +74,7 @@ func (n *NodeCommon) Dial(ctx context.Context, peerType NodeType, addr string) (
 
 	defer xerr.Contextf(&err, "%s: request identification", link)
 	// close link on error return
-	// FIXME also close link on ctx cancel
+	// FIXME also close link on ctx cancel	-> xcontext.WhenDone()
 	defer func() {
 		if err != nil {
 			link.Close()
@@ -104,8 +104,9 @@ func (n *NodeCommon) Dial(ctx context.Context, peerType NodeType, addr string) (
 		return nil, nil, fmt.Errorf("accepted, but peer is not %v (identifies as %v)", peerType, accept.NodeType)
 	}
 
-	//accept.MyNodeUUID, link // XXX register .NodeTab? (or better LinkTab as NodeTab is driven by M)
-	//accept.YourNodeUUID	// XXX M can tell us to change UUID -> take in effect
+	// XXX accept.MyUUID, link // XXX register .NodeTab? (or better LinkTab as NodeTab is driven by M)
+	// XXX accept.YourUUID	// XXX M can tell us to change UUID -> take in effect
+	// XXX accept.NumPartitions, ... wrt n.node.PartTab
 
 	return conn, accept, nil
 }

go/xcommon/xcontext/xcontext.go

@@ -172,8 +172,8 @@ func Canceled(err error) bool {
 }
 
 
-// WhenDone arranges f to be called either when ctx is cancelled or surrounding
-// function returns.
+// WhenDone arranges for f to be called either when ctx is cancelled or
+// surrounding function returns.
 //
 // To work as intended it should be called under defer like this:
 //