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package main | |
import ( | |
"fmt" | |
"os" | |
"io" | |
"encoding/binary" | |
"encoding/json" | |
"compress/gzip" | |
) | |
type Device struct { | |
Id uint `json:"id"` | |
Device string `json:"device"` | |
Ip string `json:"ip"` | |
Meta string `json:"meta"` | |
Port uint `json:"port"` | |
Region uint `json:"region"` | |
ReplicationIp string `json:"replication_ip"` | |
ReplicationPort uint `json:"replication_port"` | |
Weight float64 `json:"weight"` | |
Zone uint `json:"zone"` | |
} | |
type Ring struct { | |
Devs []Device `json:"devs"` | |
ReplicaCount uint `json:"replica_count"` | |
PartShift uint `json:"part_shift"` | |
replica2part2dev_id [][]uint16 | |
} | |
func (r Ring) GetPartitionNodes(partition uint) ([]Device) { | |
var response []Device | |
for i := uint(0); i < r.ReplicaCount ; i++ { | |
response = append(response, r.Devs[r.replica2part2dev_id[i][partition]]) | |
} | |
return response | |
} | |
func LoadRing(path string) (Ring) { | |
fp, _ := os.Open(path) | |
gz, _ := gzip.NewReader(fp) | |
magic_buf := make([]byte, 4) | |
io.ReadFull(gz, magic_buf) | |
// TODO: assert magic_buf == "R1NG" | |
var ring_version uint16 | |
binary.Read(gz, binary.BigEndian, &ring_version) | |
// TODO: assert ring_version == 1 | |
var json_len uint32 | |
binary.Read(gz, binary.BigEndian, &json_len) | |
json_buf := make([]byte, json_len) | |
io.ReadFull(gz, json_buf) | |
var ring Ring | |
json.Unmarshal(json_buf, &ring) | |
partition_count := 1 << (32 - ring.PartShift) | |
for i := uint(0); i < ring.ReplicaCount; i++ { | |
part2dev := make([]uint16, partition_count) | |
binary.Read(gz, binary.LittleEndian, &part2dev) | |
ring.replica2part2dev_id = append(ring.replica2part2dev_id, part2dev) | |
} | |
return ring | |
} | |
func main() { | |
ring := LoadRing("/etc/swift/object.ring.gz") | |
fmt.Println(ring.GetPartitionNodes(25)) | |
} |
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