seaweedfs/go/operation/lookup.go
chrislusf cc724305b6 Using Url instead of PublicUrl for volume server
Originally there are only url(ip + port), and publicUrl. Because ip was
used to listen for http service, it has less flexibility and volume
server has to be accessed via publicUrl.

Recently we added ip.bind, for binding http service.

With this change, url can be used to connect to volume servers. And
publicUrl becomes a free style piece of url information, it does not
even need to be unique.
2015-02-02 10:16:50 -08:00

119 lines
2.9 KiB
Go

package operation
import (
"encoding/json"
"errors"
"fmt"
"math/rand"
"net/url"
"strings"
"time"
"github.com/chrislusf/weed-fs/go/util"
)
type Location struct {
Url string `json:"url,omitempty"`
PublicUrl string `json:"publicUrl,omitempty"`
}
type LookupResult struct {
VolumeId string `json:"volumeId,omitempty"`
Locations []Location `json:"locations,omitempty"`
Error string `json:"error,omitempty"`
}
func (lr *LookupResult) String() string {
return fmt.Sprintf("VolumeId:%s, Locations:%v, Error:%s", lr.VolumeId, lr.Locations, lr.Error)
}
var (
vc VidCache // caching of volume locations, re-check if after 10 minutes
)
func Lookup(server string, vid string) (ret *LookupResult, err error) {
locations, cache_err := vc.Get(vid)
if cache_err != nil {
if ret, err = do_lookup(server, vid); err == nil {
vc.Set(vid, ret.Locations, 10*time.Minute)
}
} else {
ret = &LookupResult{VolumeId: vid, Locations: locations}
}
return
}
func do_lookup(server string, vid string) (*LookupResult, error) {
values := make(url.Values)
values.Add("volumeId", vid)
jsonBlob, err := util.Post("http://"+server+"/dir/lookup", values)
if err != nil {
return nil, err
}
var ret LookupResult
err = json.Unmarshal(jsonBlob, &ret)
if err != nil {
return nil, err
}
if ret.Error != "" {
return nil, errors.New(ret.Error)
}
return &ret, nil
}
func LookupFileId(server string, fileId string) (fullUrl string, err error) {
parts := strings.Split(fileId, ",")
if len(parts) != 2 {
return "", errors.New("Invalid fileId " + fileId)
}
lookup, lookupError := Lookup(server, parts[0])
if lookupError != nil {
return "", lookupError
}
if len(lookup.Locations) == 0 {
return "", errors.New("File Not Found")
}
return "http://" + lookup.Locations[rand.Intn(len(lookup.Locations))].Url + "/" + fileId, nil
}
// LookupVolumeIds find volume locations by cache and actual lookup
func LookupVolumeIds(server string, vids []string) (map[string]LookupResult, error) {
ret := make(map[string]LookupResult)
var unknown_vids []string
//check vid cache first
for _, vid := range vids {
locations, cache_err := vc.Get(vid)
if cache_err == nil {
ret[vid] = LookupResult{VolumeId: vid, Locations: locations}
} else {
unknown_vids = append(unknown_vids, vid)
}
}
//return success if all volume ids are known
if len(unknown_vids) == 0 {
return ret, nil
}
//only query unknown_vids
values := make(url.Values)
for _, vid := range unknown_vids {
values.Add("volumeId", vid)
}
jsonBlob, err := util.Post("http://"+server+"/vol/lookup", values)
if err != nil {
return nil, err
}
err = json.Unmarshal(jsonBlob, &ret)
if err != nil {
return nil, errors.New(err.Error() + " " + string(jsonBlob))
}
//set newly checked vids to cache
for _, vid := range unknown_vids {
locations := ret[vid].Locations
vc.Set(vid, locations, 10*time.Minute)
}
return ret, nil
}