seaweedfs/weed/sequence/snowflake_sequencer.go

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package sequence
import (
"fmt"
"hash/fnv"
"github.com/bwmarrin/snowflake"
"github.com/chrislusf/seaweedfs/weed/glog"
)
// a simple snowflake Sequencer
type SnowflakeSequencer struct {
node *snowflake.Node
}
func NewSnowflakeSequencer(nodeid string) (*SnowflakeSequencer, error) {
nodeid_hash := hash(nodeid) & 0x3ff
glog.V(0).Infof("use snowfalke seq id generator, nodeid:%s hex_of_nodeid: %x", nodeid, nodeid_hash)
node, err := snowflake.NewNode(int64(nodeid_hash))
if err != nil {
fmt.Println(err)
return nil, err
}
sequencer := &SnowflakeSequencer{node: node}
return sequencer, nil
}
func hash(s string) uint32 {
h := fnv.New32a()
h.Write([]byte(s))
return h.Sum32()
}
func (m *SnowflakeSequencer) NextFileId(count uint64) uint64 {
return uint64(m.node.Generate().Int64())
}
// ignore setmax as we are snowflake
func (m *SnowflakeSequencer) SetMax(seenValue uint64) {
}
// return a new id as no Peek is stored
func (m *SnowflakeSequencer) Peek() uint64 {
return uint64(m.node.Generate().Int64())
}