// Sync processes a synchrounous request and returns the response and error.
func (h *hive) Sync(ctx context.Context, req interface{}) (res interface{},
err error) {
id := uint64(rand.Int63())
ch := make(chan syncRes, 1)
// We should run this in parallel in case we are blocked on h.syncCh.
go func() {
sc := syncReqAndChan{
req: syncReq{ID: id, Data: req},
ch: ch,
}
select {
case h.syncCh <- sc:
case <-ctx.Done():
}
}()
select {
case r := <-ch:
if r.Err != nil {
return nil, errors.New(r.Err.Error())
}
return r.Data, nil
case <-ctx.Done():
return nil, ctx.Err()
}
}
// Ack acknowledges a task in the queue.
func (c *Client) Ack(ctx context.Context, queue string, task server.TaskID) (
err error) {
_, call := c.GoAck(queue, task, nil)
select {
case res := <-call:
return res.Error
case <-ctx.Done():
return ctx.Err()
}
}
func (n *MultiNode) waitElection(ctx context.Context, group uint64) {
ch := make(chan struct{})
n.pmu.Lock()
n.pendingElects[group] = append(n.pendingElects[group], ch)
n.pmu.Unlock()
select {
case <-ch:
case <-ctx.Done():
case <-n.done:
}
}
// DeQ dequeues a task from the given queue. It returns the task or an error.
func (c *Client) DeQ(ctx context.Context, queue string) (task server.Task,
err error) {
_, call := c.GoDeQ(queue, nil)
select {
case res := <-call:
if res.Error != nil {
return server.Task{}, res.Error
}
return res.Data.(server.Task), nil
case <-ctx.Done():
return server.Task{}, ctx.Err()
}
}
// EnQ enqueues a task with the given body in the queue. It returns the
// task's id or an error.
func (c *Client) EnQ(ctx context.Context, queue string, body []byte) (
id server.TaskID, err error) {
_, call := c.GoEnQ(queue, body, nil)
select {
case res := <-call:
if res.Error != nil {
return 0, res.Error
}
return res.Data.(server.TaskID), res.Error
case <-ctx.Done():
return 0, ctx.Err()
}
}
// StepBatch steps all messages in the batch. Context is used for enqueuing the
// batch and timeout is used as the maximum wait time when stepping messages
// in the batch.
func (n *MultiNode) StepBatch(ctx context.Context, batch Batch,
timeout time.Duration) error {
bt := batchTimeout{
batch: batch,
timeout: timeout,
}
select {
case n.recvc <- bt:
return nil
case <-ctx.Done():
return ctx.Err()
}
}
func (mn *multiNode) step(ctx context.Context, m multiMessage) error {
ch := mn.recvc
if m.msg.Type == pb.MsgProp {
ch = mn.propc
}
select {
case ch <- m:
return nil
case <-ctx.Done():
return ctx.Err()
case <-mn.done:
return ErrStopped
}
}
// Step advances the state machine using msgs. The ctx.Err() will be returned,
// if any.
func (n *node) step(ctx context.Context, m pb.Message) error {
ch := n.recvc
if m.Type == pb.MsgProp {
ch = n.propc
}
select {
case ch <- m:
return nil
case <-ctx.Done():
return ctx.Err()
case <-n.done:
return ErrStopped
}
}
func (n *MultiNode) Exists(ctx context.Context, gid uint64) (ok bool) {
ch := make(chan groupResponse, 1)
n.groupc <- groupRequest{
reqType: groupRequestStatus,
group: &group{id: gid},
ch: ch,
}
select {
case res := <-ch:
return res.err == nil
case <-ctx.Done():
return false
case <-n.done:
return false
}
}
func (n *MultiNode) processConfChange(ctx context.Context, group uint64,
cc raftpb.ConfChange, gn GroupNode) error {
if group == 0 || gn.Node == 0 || gn.Group != group {
glog.Fatalf("invalid group node: %v", gn)
}
id := n.genID()
req := Request{Data: gn}
var err error
cc.Context, err = n.encReq(id, req)
if err != nil {
return err
}
ch := n.line.wait(id, req)
d, err := cc.Marshal()
if err != nil {
return err
}
select {
case n.propc <- multiMessage{
group: group,
msg: raftpb.Message{
Type: raftpb.MsgProp,
Entries: []raftpb.Entry{{Type: raftpb.EntryConfChange, Data: d}},
},
}:
case <-ctx.Done():
n.line.cancel(id)
return ctx.Err()
case <-n.done:
return ErrStopped
}
select {
case res := <-ch:
return res.Err
case <-ctx.Done():
n.line.cancel(id)
return ctx.Err()
case <-n.done:
return ErrStopped
}
}
// Propose proposes the request and returns the response. This method blocks and
// returns either when the ctx is cancelled or the raft node returns a response.
func (n *MultiNode) Propose(ctx context.Context, group uint64,
req interface{}) (res interface{}, err error) {
id := n.genID()
r := Request{
Data: req,
}
d, err := n.encReq(id, r)
if err != nil {
return nil, err
}
glog.V(2).Infof("%v waits on raft request %v", n, id)
ch := n.line.wait(id, r)
mm := multiMessage{group,
raftpb.Message{
Type: raftpb.MsgProp,
Entries: []raftpb.Entry{{Data: d}},
}}
select {
case n.propc <- mm:
case <-ctx.Done():
n.line.cancel(id)
return nil, ctx.Err()
case <-n.done:
return nil, ErrStopped
}
select {
case res := <-ch:
glog.V(2).Infof("%v wakes up for raft request %v", n, id)
return res.Data, res.Err
case <-ctx.Done():
n.line.cancel(id)
return nil, ctx.Err()
case <-n.done:
return nil, ErrStopped
}
}
func (n *MultiNode) CreateGroup(ctx context.Context, cfg GroupConfig) error {
glog.V(2).Infof("creating a new group %v (%v) on node %v (%v) with peers %v",
cfg.ID, cfg.Name, n.id, n.name, cfg.Peers)
rs, ds, _, lei, _, err := OpenStorage(cfg.ID, cfg.DataDir, cfg.StateMachine)
if err != nil {
glog.Fatalf("cannot open storage: %v", err)
}
snap, err := rs.Snapshot()
if err != nil {
glog.Errorf("error in storage snapshot: %v", err)
return err
}
n.gen.StartFrom((lei + cfg.SnapCount) << 8) // To avoid conflicts.
c := &etcdraft.Config{
ID: cfg.ID,
ElectionTick: cfg.ElectionTicks,
HeartbeatTick: cfg.HeartbeatTicks,
Storage: rs,
MaxSizePerMsg: cfg.MaxMsgSize,
MaxInflightMsgs: cfg.MaxInFlights,
// TODO(soheil): Figure this one out:
// Applied: lsi,
}
g := &group{
node: n,
id: cfg.ID,
name: cfg.Name,
stateMachine: cfg.StateMachine,
raftStorage: rs,
diskStorage: ds,
applyc: make(chan etcdraft.Ready, cfg.SnapCount),
savec: make(chan readySaved, 1),
fsyncTime: cfg.FsyncTick,
snapCount: cfg.SnapCount,
snapped: snap.Metadata.Index,
applied: snap.Metadata.Index,
confState: snap.Metadata.ConfState,
stopc: make(chan struct{}),
applierDone: make(chan struct{}),
saverDone: make(chan struct{}),
}
ch := make(chan groupResponse, 1)
n.groupc <- groupRequest{
reqType: groupRequestCreate,
group: g,
config: c,
peers: cfg.Peers,
ch: ch,
}
select {
case res := <-ch:
return res.err
case <-ctx.Done():
return ctx.Err()
case <-n.done:
return ErrStopped
}
}