.

go/neo/master.go

@@ -53,6 +53,8 @@ type Master struct {
 	ctlStop     chan ctlStop	// request to stop  cluster
 	ctlShutdown chan chan error	// request to shutdown cluster XXX with ctx too ?
 
+	wantToStart chan chan error	// main -> recovery
+
 	// channels from various workers to main driver
 	nodeCome     chan nodeCome	// node connected
 	nodeLeave    chan nodeLeave	// node disconnected
@@ -95,23 +97,68 @@ func NewMaster(clusterName string) *Master {
 // XXX NotifyNodeInformation to all nodes whenever nodetab changes
 
 // XXX -> Start(), Stop()
-/*
-func (m *Master) SetClusterState(state ClusterState) error {
+
+// Start requests cluster to eventually transition into running state
+// it returns an error if such transition is not currently possible (e.g. partition table is not operational)
+// it returns nil if the transition began.
+// NOTE upon successfull return cluster is not yet in running state - the transition will
+//      take time and could be also automatically aborted due to cluster environment change (e.g.
+//      a storage node goes down)
+func (m *Master) Start() error {
 	ch := make(chan error)
-	m.ctlState <- ctlState{state, ch}
+	m.ctlStart <- ctlStart{ch}
 	return <-ch
 }
-*/
 
-// run implements main master cluster management logic: node tracking, cluster	XXX -> only top-level
+// Stop requests cluster to eventually transition into recovery state
+// XXX should be always possible ?
+func (m *Master) Stop() error {
+	ch := make(chan error)
+	m.ctlStop <- ctlStop{ch}
+	return <-ch
+}
+
+// Shutdown requests all known nodes in the cluster to stop
+func (m *Master) Shutdown() error {
+	panic("TODO")
+}
+
+func (m *Master) setClusterState(state ClusterState) {
+	m.clusterState = state
+	// TODO notify subscribers
+}
+
+
+func (m *Master) xxx(ctx ...) {
+	var err error
+
+	for ctx.Err() == nil {
+		err = recovery(ctx)
+		if err != nil {
+			return // XXX
+		}
+
+		// successful recovery -> verify
+		err = verify(ctx)
+		if err != nil {
+			continue // -> recovery
+		}
+
+		// successful verify -> service
+		err = service(ctx)
+		if err != nil {
+			// XXX what about shutdown ?
+			continue // -> recovery
+		}
+	}
+}
+
+
+// run implements main master cluster management logic: node tracking, cluster
 // state updates, scheduling data movement between storage nodes etc
 func (m *Master) run(ctx context.Context) {
 
-	// // current function to ask/control a storage depending on current cluster state
-	// // + associated context covering all storage nodes
-	// // XXX + waitgroup ?
-	// storCtl := m.storCtlRecovery
-	// storCtlCtx, storCtlCancel := context.WithCancel(ctx)
+	go m.recovery(ctx)
 
 	for {
 		select {
@@ -128,18 +175,24 @@ func (m *Master) run(ctx context.Context) {
 				break
 			}
 
-			// check preconditions for start
-			if !m.partTab.OperationalWith(&m.nodeTab) {
-				// XXX err ctx
-				// TODO + how much % PT is covered
-				c.resp <- fmt.Errorf("start: non-operational partition table")
+			ch := make(chan error)
+			select {
+			case <-ctx.Done():
+				// XXX how to avoid checking this ctx.Done everywhere?
+				c.resp <- ctx.Err()
+				panic("TODO")
+
+			case m.wantToStart <- ch:
+			}
+			err := <-ch
+			c.resp <- err
+			if err != nil {
 				break
 			}
 
-			// XXX cancel/stop/wait for current recovery task
-			// XXX start starting task
-
-
+			// recovery said it is ok to start and finished - launch verification
+			m.setClusterState(ClusterVerifying)
+			go m.verify(ctx)
 
 		// command to stop cluster
 		case <-m.ctlStop:
@@ -147,40 +200,7 @@ func (m *Master) run(ctx context.Context) {
 
 		// command to shutdown
 		case <-m.ctlShutdown:
-
-/*
-		// node connects & requests identification
-		case n := <-m.nodeCome:
-			nodeInfo, ok := m.accept(n)
-
-			if !(ok && nodeInfo.NodeType == STORAGE) {
-				break
-			}
-
-			// new storage node joined cluster
-
-			// XXX consider .clusterState change
-
-			// launch current storage control work on the joined node
-			go storCtl(storCtlCtx, n.link)
-
-			// TODO consider adjusting partTab
-
-		// node disconnects
-		case _ = <-m.nodeLeave:
 			// TODO
-
-		// a storage node came through recovery - let's see whether
-		// ptid ↑ and if so we should take partition table from there
-		case r := <-m.storRecovery:
-			if r.partTab.ptid > m.partTab.ptid {
-				m.partTab = r.partTab
-				// XXX also transfer subscribers ?
-				// XXX -> during recovery no one must be subscribed to partTab
-			}
-
-			// XXX consider clusterState change
-*/
 		}
 	}
 
@@ -205,7 +225,7 @@ func (m *Master) recovery(ctx context.Context) {
 	defer rcancel()
 	inprogress := 0
 
-	// start recovery on all storages we are currently in touch
+	// start recovery on all storages we are currently in touch with
 	for _, stor := range m.nodeTab.StorageList() {
 		if stor.Info.NodeState > DOWN {	// XXX state cmp ok ?
 			inprogress++
@@ -216,10 +236,6 @@ func (m *Master) recovery(ctx context.Context) {
 loop:
 	for {
 		select {
-		case <-ctx.Done():
-			// XXX
-			break loop
-
 		case n := <-m.nodeCome:
 			node, ok := m.accept(n, /* XXX do not accept clients */)
 			if !ok {
@@ -234,7 +250,8 @@ loop:
 			m.nodeTab.UpdateLinkDown(n.link)
 			// XXX update something indicating cluster currently can be operational or not ?
 
-		// result of a storage recovery
+		// a storage node came through recovery - let's see whether
+		// ptid ↑ and if so we should take partition table from there
 		case r := <-recovery:
 			inprogress--
 
@@ -254,9 +271,11 @@ loop:
 
 			// XXX update something indicating cluster currently can be operational or not ?
 
-		// request from master: request "ok to start?" - if ok we reply ok and exit
+
+		// request from master: "I want to start - ok?" - if ok we reply ok and exit
 		// if not ok - we just reply not ok
-		case s := <-...:
+		//case s := <-m.wantToStart:
+		case c := <-m.ctlStart:
 			if m.partTab.OperationalWith(&m.nodeTab) {
 				// reply "ok to start" after whole recovery finishes
 
@@ -267,12 +286,19 @@ loop:
 
 				rcancel()
 				defer func() {
-					s.resp <- nil
+					s <- nil
 				}()
 				break loop
 			}
 
-			s.resp <- fmt.Errorf("cluster is non-operational")
+			s <- fmt.Errorf("start: cluster is non-operational")
+
+		case c := <-m.ctlStop:
+			c.resp <- nil // we are already recovering
+
+		case <-ctx.Done():
+			// XXX
+			break loop
 		}
 	}
 
@@ -363,9 +389,7 @@ func storCtlRecovery(ctx context.Context, link *NodeLink, res chan storRecovery)
 // verify is a process that drives cluster via verification phase
 //
 // prerequisite for start: .partTab is operational wrt .nodeTab
-//
-// XXX draft: Cluster Verify if []Stor is fixed
-func (m *Master) verify(ctx context.Context, storv []*NodeLink) error {
+func (m *Master) verify(ctx context.Context) error { //, storv []*NodeLink) error {
 	// XXX ask every storage for verify and wait for _all_ them to complete?
 
 	var err error
@@ -376,17 +400,20 @@ func (m *Master) verify(ctx context.Context, storv []*NodeLink) error {
 
 	// XXX do we need to reset m.lastOid / m.lastTid to 0 in the beginning?
 
-	for _, stor := range storv {
+	// start verification on all storages we are currently in touch with
+	for _, stor := range m.nodeTab.StorageList() {
 		inprogress++
-		go storCtlVerify(vctx, stor, verify)
+		go storCtlVerify(vctx, stor.Link, verify)
 	}
 
 loop:
 	for inprogress > 0 {
 		select {
-		case <-ctx.Done():
-			err = ctx.Err()
-			break loop
+		case n := <-m.nodeCome:
+			// TODO
+
+		case n := <-m.nodeLeave:
+			// TODO
 
 		case v := <-verify:
 			inprogress--
@@ -410,6 +437,19 @@ loop:
 					m.lastTid = v.lastTid
 				}
 			}
+
+
+		case c := <-m.ctlStart:
+			c.resp <- nil // we are already starting
+
+		case c := <-m.ctlStop:
+			c.resp <- nil // ok
+			err = fmt.Errorf("stop requested")
+			break loop
+
+		case <-ctx.Done():
+			err = ctx.Err()
+			break loop
 		}
 	}
 
@@ -484,14 +524,39 @@ func storCtlVerify(ctx context.Context, link *NodeLink, res chan storVerify) {
 
 // service is the process that drives cluster during running state
 //
-// XXX draft: Cluster Running if []Stor is fixed
-func (m *Master) service(ctx context.Context, storv []*NodeLink) {
-	// TODO
-}
+func (m *Master) service(ctx context.Context) {
 
-// XXX draft: Cluster Stopping if []Stor is fixed
-func (m *Master) stop(ctx context.Context, storv []*NodeLink) {
-	// TODO
+loop:
+	for {
+		select {
+		case n := <-m.nodeCome:
+			// TODO
+
+		case n := <-m.nodeLeave:
+			// TODO
+
+
+		// XXX what else ?	(-> txn control at least)
+
+		case c := <-m.ctlStart:
+			c.resp <- nil // we are already started
+
+		case c := <-m.ctlStop:
+			c.resp <- nil // ok
+			err = fmt.Errorf("stop requested")
+			break loop
+
+		case <-ctx.Done():
+			err = ctx.Err()
+			break loop
+		}
+	}
+
+	if err != nil {
+		// TODO
+	}
+
+	return err
 }
 
 // accept processes identification request of just connected node and either accepts or declines it