本文整理汇总了Golang中github.com/heems/bssim/Godeps/_workspace/src/golang.org/x/net/context.Context类的典型用法代码示例。如果您正苦于以下问题:Golang Context类的具体用法?Golang Context怎么用?Golang Context使用的例子?那么恭喜您, 这里精选的类代码示例或许可以为您提供帮助。
在下文中一共展示了Context类的20个代码示例,这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞,您的评价将有助于我们的系统推荐出更棒的Golang代码示例。
示例1: providerConnector
// connects to providers for the given keys
func (bs *Bitswap) providerConnector(parent context.Context) {
defer log.Info("bitswap client worker shutting down...")
for {
log.Event(parent, "Bitswap.ProviderConnector.Loop")
select {
case req := <-bs.findKeys:
keys := req.keys
if len(keys) == 0 {
log.Warning("Received batch request for zero blocks")
continue
}
log.Event(parent, "Bitswap.ProviderConnector.Work", eventlog.LoggableMap{"Keys": keys})
// NB: Optimization. Assumes that providers of key[0] are likely to
// be able to provide for all keys. This currently holds true in most
// every situation. Later, this assumption may not hold as true.
child, cancel := context.WithTimeout(req.ctx, providerRequestTimeout)
providers := bs.network.FindProvidersAsync(child, keys[0], maxProvidersPerRequest)
for p := range providers {
go bs.network.ConnectTo(req.ctx, p)
}
cancel()
case <-parent.Done():
return
}
}
}
开发者ID:rht,项目名称:bssim,代码行数:30,代码来源:workers.go
示例2: process
func (cq *ChanQueue) process(ctx context.Context) {
// construct the channels here to be able to use them bidirectionally
enqChan := make(chan peer.ID)
deqChan := make(chan peer.ID)
cq.EnqChan = enqChan
cq.DeqChan = deqChan
go func() {
log.Debug("processing")
defer log.Debug("closed")
defer close(deqChan)
var next peer.ID
var item peer.ID
var more bool
for {
if cq.Queue.Len() == 0 {
// log.Debug("wait for enqueue")
select {
case next, more = <-enqChan:
if !more {
return
}
// log.Debug("got", next)
case <-ctx.Done():
return
}
} else {
next = cq.Queue.Dequeue()
// log.Debug("peek", next)
}
select {
case item, more = <-enqChan:
if !more {
if cq.Queue.Len() > 0 {
return // we're done done.
}
enqChan = nil // closed, so no use.
}
// log.Debug("got", item)
cq.Queue.Enqueue(item)
cq.Queue.Enqueue(next) // order may have changed.
next = ""
case deqChan <- next:
// log.Debug("dequeued", next)
next = ""
case <-ctx.Done():
return
}
}
}()
}
开发者ID:rht,项目名称:bssim,代码行数:60,代码来源:sync.go
示例3: rebroadcastWorker
func (bs *Bitswap) rebroadcastWorker(parent context.Context) {
ctx, cancel := context.WithCancel(parent)
defer cancel()
broadcastSignal := time.NewTicker(rebroadcastDelay.Get())
defer broadcastSignal.Stop()
tick := time.NewTicker(10 * time.Second)
defer tick.Stop()
for {
log.Event(ctx, "Bitswap.Rebroadcast.idle")
select {
case <-tick.C:
n := bs.wm.wl.Len()
if n > 0 {
log.Debug(n, "keys in bitswap wantlist")
}
case <-broadcastSignal.C: // resend unfulfilled wantlist keys
log.Event(ctx, "Bitswap.Rebroadcast.active")
entries := bs.wm.wl.Entries()
if len(entries) > 0 {
bs.connectToProviders(ctx, entries)
}
case <-parent.Done():
return
}
}
}
开发者ID:rht,项目名称:bssim,代码行数:29,代码来源:workers.go
示例4: GetBlocks
// GetBlocks returns a channel where the caller may receive blocks that
// correspond to the provided |keys|. Returns an error if BitSwap is unable to
// begin this request within the deadline enforced by the context.
//
// NB: Your request remains open until the context expires. To conserve
// resources, provide a context with a reasonably short deadline (ie. not one
// that lasts throughout the lifetime of the server)
func (bs *Bitswap) GetBlocks(ctx context.Context, keys []key.Key) (<-chan *blocks.Block, error) {
select {
case <-bs.process.Closing():
return nil, errors.New("bitswap is closed")
default:
}
promise := bs.notifications.Subscribe(ctx, keys...)
for _, k := range keys {
log.Event(ctx, "Bitswap.GetBlockRequest.Start", &k)
}
bs.wm.WantBlocks(keys)
req := &blockRequest{
keys: keys,
ctx: ctx,
}
select {
case bs.findKeys <- req:
return promise, nil
case <-ctx.Done():
return nil, ctx.Err()
}
}
开发者ID:rht,项目名称:bssim,代码行数:32,代码来源:bitswap.go
示例5: GetBlocks
// GetBlocks gets a list of blocks asynchronously and returns through
// the returned channel.
// NB: No guarantees are made about order.
func (s *BlockService) GetBlocks(ctx context.Context, ks []key.Key) <-chan *blocks.Block {
out := make(chan *blocks.Block, 0)
go func() {
defer close(out)
var misses []key.Key
for _, k := range ks {
hit, err := s.Blockstore.Get(k)
if err != nil {
misses = append(misses, k)
continue
}
log.Debug("Blockservice: Got data in datastore.")
select {
case out <- hit:
case <-ctx.Done():
return
}
}
rblocks, err := s.Exchange.GetBlocks(ctx, misses)
if err != nil {
log.Debugf("Error with GetBlocks: %s", err)
return
}
for b := range rblocks {
select {
case out <- b:
case <-ctx.Done():
return
}
}
}()
return out
}
开发者ID:rht,项目名称:bssim,代码行数:38,代码来源:blockservice.go
示例6: Subscribe
// Subscribe returns a channel of blocks for the given |keys|. |blockChannel|
// is closed if the |ctx| times out or is cancelled, or after sending len(keys)
// blocks.
func (ps *impl) Subscribe(ctx context.Context, keys ...key.Key) <-chan *blocks.Block {
blocksCh := make(chan *blocks.Block, len(keys))
valuesCh := make(chan interface{}, len(keys)) // provide our own channel to control buffer, prevent blocking
if len(keys) == 0 {
close(blocksCh)
return blocksCh
}
ps.wrapped.AddSubOnceEach(valuesCh, toStrings(keys)...)
go func() {
defer close(blocksCh)
defer ps.wrapped.Unsub(valuesCh) // with a len(keys) buffer, this is an optimization
for {
select {
case <-ctx.Done():
return
case val, ok := <-valuesCh:
if !ok {
return
}
block, ok := val.(*blocks.Block)
if !ok {
return
}
select {
case <-ctx.Done():
return
case blocksCh <- block: // continue
}
}
}
}()
return blocksCh
}
开发者ID:rht,项目名称:bssim,代码行数:38,代码来源:notifications.go
示例7: GetBlocks
func (e *offlineExchange) GetBlocks(ctx context.Context, ks []key.Key) (<-chan *blocks.Block, error) {
out := make(chan *blocks.Block, 0)
go func() {
defer close(out)
var misses []key.Key
for _, k := range ks {
hit, err := e.bs.Get(k)
if err != nil {
misses = append(misses, k)
// a long line of misses should abort when context is cancelled.
select {
// TODO case send misses down channel
case <-ctx.Done():
return
default:
continue
}
}
select {
case out <- hit:
case <-ctx.Done():
return
}
}
}()
return out, nil
}
开发者ID:rht,项目名称:bssim,代码行数:27,代码来源:offline.go
示例8: provideCollector
func (bs *Bitswap) provideCollector(ctx context.Context) {
defer close(bs.provideKeys)
var toProvide []key.Key
var nextKey key.Key
var keysOut chan key.Key
for {
select {
case blk, ok := <-bs.newBlocks:
if !ok {
log.Debug("newBlocks channel closed")
return
}
if keysOut == nil {
nextKey = blk.Key()
keysOut = bs.provideKeys
} else {
toProvide = append(toProvide, blk.Key())
}
case keysOut <- nextKey:
if len(toProvide) > 0 {
nextKey = toProvide[0]
toProvide = toProvide[1:]
} else {
keysOut = nil
}
case <-ctx.Done():
return
}
}
}
开发者ID:rht,项目名称:bssim,代码行数:31,代码来源:workers.go
示例9: LogError
// LogError logs the error to the owner of the context.
//
// If this context was created with ContextWithErrorLog, then this method
// passes the error to context creator over an unbuffered channel.
//
// If this context was created by other means, this method is a no-op.
func LogError(ctx context.Context, err error) {
v := ctx.Value(errLogKey)
errs, ok := v.(privateChanType)
if !ok {
return
}
errs <- err
}
开发者ID:rht,项目名称:bssim,代码行数:14,代码来源:context.go
示例10: gatedDialAttempt
// gatedDialAttempt is an attempt to dial a node. It is gated by the swarm's
// dial synchronization systems: dialsync and dialbackoff.
func (s *Swarm) gatedDialAttempt(ctx context.Context, p peer.ID) (*Conn, error) {
var logdial = lgbl.Dial("swarm", s.LocalPeer(), p, nil, nil)
defer log.EventBegin(ctx, "swarmDialAttemptSync", logdial).Done()
// check if we already have an open connection first
conn := s.bestConnectionToPeer(p)
if conn != nil {
return conn, nil
}
// check if there's an ongoing dial to this peer
if ok, wait := s.dsync.Lock(p); ok {
// ok, we have been charged to dial! let's do it.
// if it succeeds, dial will add the conn to the swarm itself.
defer log.EventBegin(ctx, "swarmDialAttemptStart", logdial).Done()
ctxT, cancel := context.WithTimeout(ctx, s.dialT)
conn, err := s.dial(ctxT, p)
cancel()
s.dsync.Unlock(p)
log.Debugf("dial end %s", conn)
if err != nil {
log.Event(ctx, "swarmDialBackoffAdd", logdial)
s.backf.AddBackoff(p) // let others know to backoff
// ok, we failed. try again. (if loop is done, our error is output)
return nil, fmt.Errorf("dial attempt failed: %s", err)
}
log.Event(ctx, "swarmDialBackoffClear", logdial)
s.backf.Clear(p) // okay, no longer need to backoff
return conn, nil
} else {
// we did not dial. we must wait for someone else to dial.
// check whether we should backoff first...
if s.backf.Backoff(p) {
log.Event(ctx, "swarmDialBackoff", logdial)
return nil, ErrDialBackoff
}
defer log.EventBegin(ctx, "swarmDialWait", logdial).Done()
select {
case <-wait: // wait for that other dial to finish.
// see if it worked, OR we got an incoming dial in the meantime...
conn := s.bestConnectionToPeer(p)
if conn != nil {
return conn, nil
}
return nil, ErrDialFailed
case <-ctx.Done(): // or we may have to bail...
return nil, ctx.Err()
}
}
}
开发者ID:rht,项目名称:bssim,代码行数:58,代码来源:swarm_dial.go
示例11: MetadataFromContext
func MetadataFromContext(ctx context.Context) (Metadata, error) {
value := ctx.Value(metadataKey)
if value != nil {
metadata, ok := value.(Metadata)
if ok {
return metadata, nil
}
}
return nil, errors.New("context contains no metadata")
}
开发者ID:rht,项目名称:bssim,代码行数:10,代码来源:context.go
示例12: AddProvider
func (pm *ProviderManager) AddProvider(ctx context.Context, k key.Key, val peer.ID) {
prov := &addProv{
k: k,
val: val,
}
select {
case pm.newprovs <- prov:
case <-ctx.Done():
}
}
开发者ID:rht,项目名称:bssim,代码行数:10,代码来源:providers.go
示例13: WithContextAndTeardown
// WithContextAndTeardown is a helper function to set teardown at initiation
// of WithContext
func WithContextAndTeardown(ctx context.Context, tf goprocess.TeardownFunc) goprocess.Process {
if ctx == nil {
panic("nil Context")
}
p := goprocess.WithTeardown(tf)
go func() {
<-ctx.Done()
p.Close()
}()
return p
}
开发者ID:rht,项目名称:bssim,代码行数:13,代码来源:context.go
示例14: runQueue
func (mq *msgQueue) runQueue(ctx context.Context) {
for {
select {
case <-mq.work: // there is work to be done
mq.doWork(ctx)
case <-mq.done:
return
case <-ctx.Done():
return
}
}
}
开发者ID:rht,项目名称:bssim,代码行数:12,代码来源:wantmanager.go
示例15: CloseAfterContext
// CloseAfterContext schedules the process to close after the given
// context is done. It is the equivalent of:
//
// func CloseAfterContext(p goprocess.Process, ctx context.Context) {
// go func() {
// <-ctx.Done()
// p.Close()
// }()
// }
//
func CloseAfterContext(p goprocess.Process, ctx context.Context) {
if p == nil {
panic("nil Process")
}
if ctx == nil {
panic("nil Context")
}
go func() {
<-ctx.Done()
p.Close()
}()
}
开发者ID:rht,项目名称:bssim,代码行数:23,代码来源:context.go
示例16: WithDeadlineFraction
// WithDeadlineFraction returns a Context with a fraction of the
// original context's timeout. This is useful in sequential pipelines
// of work, where one might try options and fall back to others
// depending on the time available, or failure to respond. For example:
//
// // getPicture returns a picture from our encrypted database
// // we have a pipeline of multiple steps. we need to:
// // - get the data from a database
// // - decrypt it
// // - apply many transforms
// //
// // we **know** that each step takes increasingly more time.
// // The transforms are much more expensive than decryption, and
// // decryption is more expensive than the database lookup.
// // If our database takes too long (i.e. >0.2 of available time),
// // there's no use in continuing.
// func getPicture(ctx context.Context, key string) ([]byte, error) {
// // fractional timeout contexts to the rescue!
//
// // try the database with 0.2 of remaining time.
// ctx1, _ := ctxext.WithDeadlineFraction(ctx, 0.2)
// val, err := db.Get(ctx1, key)
// if err != nil {
// return nil, err
// }
//
// // try decryption with 0.3 of remaining time.
// ctx2, _ := ctxext.WithDeadlineFraction(ctx, 0.3)
// if val, err = decryptor.Decrypt(ctx2, val); err != nil {
// return nil, err
// }
//
// // try transforms with all remaining time. hopefully it's enough!
// return transformer.Transform(ctx, val)
// }
//
//
func WithDeadlineFraction(ctx context.Context, fraction float64) (
context.Context, context.CancelFunc) {
d, found := ctx.Deadline()
if !found { // no deadline
return context.WithCancel(ctx)
}
left := d.Sub(time.Now())
if left < 0 { // already passed...
return context.WithCancel(ctx)
}
left = time.Duration(float64(left) * fraction)
return context.WithTimeout(ctx, left)
}
开发者ID:rht,项目名称:bssim,代码行数:53,代码来源:fracctx.go
示例17: PublishQueryEvent
func PublishQueryEvent(ctx context.Context, ev *QueryEvent) {
ich := ctx.Value(RoutingQueryKey)
if ich == nil {
return
}
ch, ok := ich.(chan<- *QueryEvent)
if !ok {
return
}
select {
case ch <- ev:
case <-ctx.Done():
}
}
开发者ID:rht,项目名称:bssim,代码行数:16,代码来源:query.go
示例18: GetProviders
func (pm *ProviderManager) GetProviders(ctx context.Context, k key.Key) []peer.ID {
gp := &getProv{
k: k,
resp: make(chan []peer.ID, 1), // buffered to prevent sender from blocking
}
select {
case <-ctx.Done():
return nil
case pm.getprovs <- gp:
}
select {
case <-ctx.Done():
return nil
case peers := <-gp.resp:
return peers
}
}
开发者ID:rht,项目名称:bssim,代码行数:17,代码来源:providers.go
示例19: FindProvidersAsync
func (c *client) FindProvidersAsync(ctx context.Context, k key.Key, max int) <-chan peer.PeerInfo {
out := make(chan peer.PeerInfo)
go func() {
defer close(out)
for i, p := range c.server.Providers(k) {
if max <= i {
return
}
select {
case out <- p:
case <-ctx.Done():
return
}
}
}()
return out
}
开发者ID:rht,项目名称:bssim,代码行数:17,代码来源:centralized_client.go
示例20: Bootstrap
// Bootstrap ensures the dht routing table remains healthy as peers come and go.
// it builds up a list of peers by requesting random peer IDs. The Bootstrap
// process will run a number of queries each time, and run every time signal fires.
// These parameters are configurable.
//
// As opposed to BootstrapWithConfig, Bootstrap satisfies the routing interface
func (dht *IpfsDHT) Bootstrap(ctx context.Context) error {
proc, err := dht.BootstrapWithConfig(DefaultBootstrapConfig)
if err != nil {
return err
}
// wait till ctx or dht.Context exits.
// we have to do it this way to satisfy the Routing interface (contexts)
go func() {
defer proc.Close()
select {
case <-ctx.Done():
case <-dht.Context().Done():
}
}()
return nil
}
开发者ID:rht,项目名称:bssim,代码行数:24,代码来源:dht_bootstrap.go
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