Beispiel #1
0
func newFromConfig(ld blobserver.Loader, config jsonconfig.Obj) (storage blobserver.Storage, err error) {
	sto := &replicaStorage{
		replicaPrefixes: config.RequiredList("backends"),
		readPrefixes:    config.OptionalList("readBackends"),
	}
	nReplicas := len(sto.replicaPrefixes)
	sto.minWritesForSuccess = config.OptionalInt("minWritesForSuccess", nReplicas)
	if err := config.Validate(); err != nil {
		return nil, err
	}
	if nReplicas == 0 {
		return nil, errors.New("replica: need at least one replica")
	}
	if sto.minWritesForSuccess == 0 {
		sto.minWritesForSuccess = nReplicas
	}
	// readPrefixes defaults to the write prefixes.
	if len(sto.readPrefixes) == 0 {
		sto.readPrefixes = sto.replicaPrefixes
	}

	for _, prefix := range sto.replicaPrefixes {
		s, err := ld.GetStorage(prefix)
		if err != nil {
			// If it's not a storage interface, it might be an http Handler
			// that also supports being a target (e.g. a sync handler).
			h, _ := ld.GetHandler(prefix)
			var ok bool
			if s, ok = h.(blobserver.Storage); !ok {
				return nil, err
			}
		}
		sto.replicas = append(sto.replicas, s)
	}
	for _, prefix := range sto.readPrefixes {
		s, err := ld.GetStorage(prefix)
		if err != nil {
			return nil, err
		}
		sto.readReplicas = append(sto.readReplicas, s)
	}
	return sto, nil
}
Beispiel #2
0
func newFromConfig(ld blobserver.Loader, config jsonconfig.Obj) (storage blobserver.Storage, err error) {
	sto := &shardStorage{
		shardPrefixes: config.RequiredList("backends"),
	}
	if err := config.Validate(); err != nil {
		return nil, err
	}
	if len(sto.shardPrefixes) == 0 {
		return nil, errors.New("shard: need at least one shard")
	}
	sto.shards = make([]blobserver.Storage, len(sto.shardPrefixes))
	for i, prefix := range sto.shardPrefixes {
		shardSto, err := ld.GetStorage(prefix)
		if err != nil {
			return nil, err
		}
		sto.shards[i] = shardSto
	}
	return sto, nil
}