Golang context.Context类代码示例

func (sto *appengineStorage) EnumerateBlobs(ctx *context.Context, dest chan<- blob.SizedRef, after string, limit int) error {
	defer close(dest)

	loan := ctxPool.Get()
	defer loan.Return()
	actx := loan

	prefix := sto.namespace + "|"
	keyBegin := datastore.NewKey(actx, memKind, prefix+after, 0, nil)
	keyEnd := datastore.NewKey(actx, memKind, sto.namespace+"~", 0, nil)

	q := datastore.NewQuery(memKind).Limit(int(limit)).Filter("__key__>", keyBegin).Filter("__key__<", keyEnd)
	it := q.Run(actx)
	var row memEnt
	for {
		key, err := it.Next(&row)
		if err == datastore.Done {
			break
		}
		if err != nil {
			return err
		}
		select {
		case dest <- blob.SizedRef{blob.ParseOrZero(key.StringID()[len(prefix):]), row.Size}:
		case <-ctx.Done():
			return context.ErrCanceled
		}
	}
	return nil
}

func (ns *nsto) EnumerateBlobs(ctx *context.Context, dest chan<- blob.SizedRef, after string, limit int) error {
	defer close(dest)
	done := ctx.Done()

	it := ns.inventory.Find(after, "")
	first := true
	for limit > 0 && it.Next() {
		if first {
			first = false
			if after != "" && it.Key() == after {
				continue
			}
		}
		br, ok := blob.ParseBytes(it.KeyBytes())
		size, err := strutil.ParseUintBytes(it.ValueBytes(), 10, 32)
		if !ok || err != nil {
			log.Printf("Bogus namespace key %q / value %q", it.Key(), it.Value())
			continue
		}
		select {
		case dest <- blob.SizedRef{br, uint32(size)}:
		case <-done:
			return context.ErrCanceled
		}
		limit--
	}
	if err := it.Close(); err != nil {
		return err
	}
	return nil
}

// EnumeratePermanodesLastModified sends all permanodes, sorted by most recently modified first, to ch,
// or until ctx is done.
//
// The Corpus must already be locked with RLock.
func (c *Corpus) EnumeratePermanodesLastModifiedLocked(ctx *context.Context, ch chan<- camtypes.BlobMeta) error {
	defer close(ch)

	// TODO: keep these sorted in memory
	pns := make([]pnAndTime, 0, len(c.permanodes))
	for pn := range c.permanodes {
		if modt, ok := c.PermanodeModtimeLocked(pn); ok {
			pns = append(pns, pnAndTime{pn, modt})
		}
	}
	sort.Sort(sort.Reverse(byPermanodeModtime(pns)))
	for _, cand := range pns {
		bm := c.blobs[cand.pn]
		if bm == nil {
			continue
		}
		select {
		case ch <- *bm:
			continue
		case <-ctx.Done():
			return context.ErrCanceled
		}
	}
	return nil
}

// ctx will be canceled on failure
func (c *Collector) markItem(ctx *context.Context, it Item, isRoot bool) error {
	if !isRoot {
		marked, err := c.Marker.IsMarked(it)
		if err != nil {
			return err
		}
		if marked {
			return nil
		}
	}
	if err := c.Marker.Mark(it); err != nil {
		return err
	}

	ch := make(chan Item, buffered)
	var grp syncutil.Group
	grp.Go(func() error {
		return c.ItemEnumerator.EnumerateItem(ctx, it, ch)
	})
	grp.Go(func() error {
		for it := range ch {
			if err := c.markItem(ctx, it, false); err != nil {
				return err
			}
		}
		return nil
	})
	if err := grp.Err(); err != nil {
		ctx.Cancel()
		return err
	}
	return nil
}

func (sto *s3Storage) EnumerateBlobs(ctx *context.Context, dest chan<- blob.SizedRef, after string, limit int) (err error) {
	defer close(dest)
	if faultEnumerate.FailErr(&err) {
		return
	}
	startAt := after
	if _, ok := blob.Parse(after); ok {
		startAt = nextStr(after)
	}
	objs, err := sto.s3Client.ListBucket(sto.bucket, startAt, limit)
	if err != nil {
		log.Printf("s3 ListBucket: %v", err)
		return err
	}
	for _, obj := range objs {
		if obj.Key == after {
			continue
		}
		br, ok := blob.Parse(obj.Key)
		if !ok {
			continue
		}
		select {
		case dest <- blob.SizedRef{Ref: br, Size: uint32(obj.Size)}:
		case <-ctx.Done():
			return context.ErrCanceled
		}
	}
	return nil
}

func (s *storage) EnumerateBlobs(ctx *context.Context, dest chan<- blob.SizedRef, after string, limit int) (err error) {
	defer close(dest)

	t := s.index.Find(after, "")
	defer func() {
		closeErr := t.Close()
		if err == nil {
			err = closeErr
		}
	}()
	for i := 0; i < limit && t.Next(); {
		key := t.Key()
		if key <= after {
			// EnumerateBlobs' semantics are '>', but sorted.KeyValue.Find is '>='.
			continue
		}
		br, ok := blob.Parse(key)
		if !ok {
			return fmt.Errorf("diskpacked: couldn't parse index key %q", key)
		}
		m, ok := parseBlobMeta(t.Value())
		if !ok {
			return fmt.Errorf("diskpacked: couldn't parse index value %q: %q", key, t.Value())
		}
		select {
		case dest <- m.SizedRef(br):
		case <-ctx.Done():
			return context.ErrCanceled
		}
		i++
	}
	return nil
}

func (ix *Index) EnumerateBlobs(ctx *context.Context, dest chan<- blob.SizedRef, after string, limit int) (err error) {
	defer close(dest)
	it := ix.s.Find("have:"+after, "have~")
	defer func() {
		closeErr := it.Close()
		if err == nil {
			err = closeErr
		}
	}()

	n := int(0)
	for n < limit && it.Next() {
		k := it.Key()
		if k <= after {
			continue
		}
		if !strings.HasPrefix(k, "have:") {
			break
		}
		n++
		br, ok := blob.Parse(k[len("have:"):])
		size, err := strconv.ParseUint(it.Value(), 10, 32)
		if ok && err == nil {
			select {
			case dest <- blob.SizedRef{br, int64(size)}:
			case <-ctx.Done():
				return context.ErrCanceled
			}
		}
	}
	return nil
}

func (s *Storage) EnumerateBlobs(ctx *context.Context, dest chan<- blob.SizedRef, after string, limit int) error {
	defer close(dest)
	s.mu.RLock()
	defer s.mu.RUnlock()

	// TODO(bradfitz): care about keeping this sorted like we used
	// to? I think it was more expensive than it was worth before,
	// since maintaining it was more costly than how often it was
	// used. But perhaps it'd make sense to maintain it lazily:
	// construct it on EnumerateBlobs but invalidate it everywhere
	// else.  Probably doesn't matter much.
	sorted := make([]blob.Ref, 0, len(s.m))
	for br := range s.m {
		sorted = append(sorted, br)
	}
	sort.Sort(blob.ByRef(sorted))

	n := 0
	for _, br := range sorted {
		if after != "" && br.String() <= after {
			continue
		}
		select {
		case dest <- blob.SizedRef{br, uint32(len(s.m[br]))}:
		case <-ctx.Done():
			return context.ErrCanceled
		}
		n++
		if limit > 0 && n == limit {
			break
		}
	}
	return nil
}

func (m *mongoStorage) EnumerateBlobs(ctx *context.Context, dest chan<- blob.SizedRef, after string, limit int) error {
	defer close(dest)

	var b blobDoc
	var qry bson.M
	if after != "" {
		qry = bson.M{"key": bson.M{"$gt": after}}
	}
	iter := m.c.Find(qry).Limit(limit).Select(bson.M{"key": 1, "size": 1}).Sort("key").Iter()

	for iter.Next(&b) {
		br, ok := blob.Parse(b.Key)
		if !ok {
			continue
		}
		select {
		case dest <- blob.SizedRef{Ref: br, Size: uint32(b.Size)}:
		case <-ctx.Done():
			// Close the iterator but ignore the error value since we are already cancelling
			if err := iter.Close(); err != nil {
				log.Printf("Error closing iterator after enumerating: %v", err)
			}
			return context.ErrCanceled
		}
	}

	if err := iter.Close(); err != nil {
		return err
	}

	return nil
}

func (s *Storage) StreamBlobs(ctx *context.Context, dest chan<- blobserver.BlobAndToken, contToken string) error {
	// for this impl, contToken is >= blobref.String()
	defer close(dest)
	s.mu.RLock()
	defer s.mu.RUnlock()

	sorted := make([]blob.Ref, 0, len(s.m))
	for br := range s.m {
		sorted = append(sorted, br)
	}
	sort.Sort(blob.ByRef(sorted))

	for _, br := range sorted {
		if br.String() < contToken {
			continue
		}
		select {
		case <-ctx.Done():
			return context.ErrCanceled
		case dest <- blobserver.BlobAndToken{
			Blob: blob.NewBlob(br, uint32(len(s.m[br])), func() types.ReadSeekCloser {
				return blob.NewLazyReadSeekCloser(s, br)
			}),
			Token: br.String(),
		}:
		}
	}
	return nil
}

func (s *storage) EnumerateBlobs(ctx *context.Context, dest chan<- blob.SizedRef, after string, limit int) error {
	defer close(dest)
	iter := s.index.Find(after, "")
	n := 0
	for iter.Next() {
		if iter.Key() == after {
			continue
		}
		br, ok := blob.Parse(iter.Key())
		if !ok {
			panic("Bogus encrypt index key: " + iter.Key())
		}
		plainSize, ok := parseMetaValuePlainSize(iter.Value())
		if !ok {
			panic("Bogus encrypt index value: " + iter.Value())
		}
		select {
		case dest <- blob.SizedRef{br, plainSize}:
		case <-ctx.Done():
			return context.ErrCanceled
		}
		n++
		if limit != 0 && n >= limit {
			break
		}
	}
	return iter.Close()
}

// setFirewall adds the firewall rules needed for ports 80 & 433 to the default network.
func (d *Deployer) setFirewall(ctx *context.Context, computeService *compute.Service) error {
	defaultNet, err := computeService.Networks.Get(d.Conf.Project, "default").Do()
	if err != nil {
		return fmt.Errorf("error getting default network: %v", err)
	}

	needRules := map[string]compute.Firewall{
		"default-allow-http": compute.Firewall{
			Name:         "default-allow-http",
			SourceRanges: []string{"0.0.0.0/0"},
			SourceTags:   []string{"http-server"},
			Allowed:      []*compute.FirewallAllowed{{"tcp", []string{"80"}}},
			Network:      defaultNet.SelfLink,
		},
		"default-allow-https": compute.Firewall{
			Name:         "default-allow-https",
			SourceRanges: []string{"0.0.0.0/0"},
			SourceTags:   []string{"https-server"},
			Allowed:      []*compute.FirewallAllowed{{"tcp", []string{"443"}}},
			Network:      defaultNet.SelfLink,
		},
	}

	rules, err := computeService.Firewalls.List(d.Conf.Project).Do()
	if err != nil {
		return fmt.Errorf("error listing rules: %v", err)
	}
	for _, it := range rules.Items {
		delete(needRules, it.Name)
	}
	if len(needRules) == 0 {
		return nil
	}

	if Verbose {
		log.Printf("Need to create rules: %v", needRules)
	}
	var wg syncutil.Group
	for name, rule := range needRules {
		if ctx.IsCanceled() {
			return context.ErrCanceled
		}
		name, rule := name, rule
		wg.Go(func() error {
			if Verbose {
				log.Printf("Creating rule %s", name)
			}
			r, err := computeService.Firewalls.Insert(d.Conf.Project, &rule).Do()
			if err != nil {
				return fmt.Errorf("error creating rule %s: %v", name, err)
			}
			if Verbose {
				log.Printf("Created rule %s: %+v", name, r)
			}
			return nil
		})
	}
	return wg.Err()
}

// contToken is of forms:
//    ""                : start from beginning of zip files
//    "sha1-xxxxx:n"    : start at == (sha1-xxxx, file n), else next zip
func (st largeBlobStreamer) StreamBlobs(ctx *context.Context, dest chan<- blobserver.BlobAndToken, contToken string) (err error) {
	defer close(dest)
	s := st.sto
	large := s.large

	var after string // for enumerateAll
	var skipFiles int
	var firstRef blob.Ref // first we care about

	if contToken != "" {
		f := strings.SplitN(contToken, ":", 2)
		if len(f) != 2 {
			return errContToken
		}
		firstRef, _ = blob.Parse(f[0])
		skipFiles, err = strconv.Atoi(f[1])
		if !firstRef.Valid() || err != nil {
			return errContToken
		}
		// EnumerateAllFrom takes a cursor that's greater, but
		// we want to start _at_ firstRef. So start
		// enumerating right before our target.
		after = firstRef.StringMinusOne()
	}
	return blobserver.EnumerateAllFrom(ctx, large, after, func(sb blob.SizedRef) error {
		if firstRef.Valid() {
			if sb.Ref.Less(firstRef) {
				// Skip.
				return nil
			}
			if firstRef.Less(sb.Ref) {
				skipFiles = 0 // reset it.
			}
		}
		fileN := 0
		return s.foreachZipBlob(sb.Ref, func(bap BlobAndPos) error {
			if skipFiles > 0 {
				skipFiles--
				fileN++
				return nil
			}
			select {
			case dest <- blobserver.BlobAndToken{
				Blob: blob.NewBlob(bap.Ref, bap.Size, func() types.ReadSeekCloser {
					return blob.NewLazyReadSeekCloser(s, bap.Ref)
				}),
				Token: fmt.Sprintf("%s:%d", sb.Ref, fileN),
			}:
				fileN++
				return nil
			case <-ctx.Done():
				return context.ErrCanceled
			}
		})
	})
}

// doDest is false for source and true for dest.
func (sh *SyncHandler) startValidatePrefix(ctx *context.Context, pfx string, doDest bool) (<-chan blob.SizedRef, <-chan error) {
	var e blobserver.BlobEnumerator
	if doDest {
		e = sh.to
	} else {
		e = sh.from
	}
	c := make(chan blob.SizedRef, 64)
	errc := make(chan error, 1)
	go func() {
		defer close(c)
		var last string // last blobref seen; to double check storage's enumeration works correctly.
		err := blobserver.EnumerateAllFrom(ctx, e, pfx, func(sb blob.SizedRef) error {
			// Just double-check that the storage target is returning sorted results correctly.
			brStr := sb.Ref.String()
			if brStr < pfx {
				log.Fatalf("Storage target %T enumerate not behaving: %q < requested prefix %q", e, brStr, pfx)
			}
			if last != "" && last >= brStr {
				log.Fatalf("Storage target %T enumerate not behaving: previous %q >= current %q", e, last, brStr)
			}
			last = brStr

			// TODO: could add a more efficient method on blob.Ref to do this,
			// that doesn't involve call String().
			if !strings.HasPrefix(brStr, pfx) {
				return errNotPrefix
			}
			select {
			case c <- sb:
				sh.mu.Lock()
				if doDest {
					sh.vdestCount++
					sh.vdestBytes += int64(sb.Size)
				} else {
					sh.vsrcCount++
					sh.vsrcBytes += int64(sb.Size)
				}
				sh.mu.Unlock()
				return nil
			case <-ctx.Done():
				return context.ErrCanceled
			}
		})
		if err == errNotPrefix {
			err = nil
		}
		if err != nil {
			// Send a zero value to shut down ListMissingDestinationBlobs.
			c <- blob.SizedRef{}
		}
		errc <- err
	}()
	return c, errc
}

func (s testEnum) Enumerate(ctx *context.Context, dest chan<- Item) error {
	defer close(dest)
	for _, v := range s {
		select {
		case dest <- v:
		case <-ctx.Done():
			return context.ErrCanceled
		}
	}
	return nil
}