sdk/go/src/arvados.org/keepclient/support.go

   1 /* Internal methods to support keepclient.go */
   2 package keepclient
   3
   4 import (
   5         "arvados.org/streamer"
   6         "encoding/json"
   7         "errors"
   8         "fmt"
   9         "io"
  10         "io/ioutil"
  11         "log"
  12         "net/http"
  13         "os"
  14         "strconv"
  15         "strings"
  16 )
  17
  18 type keepDisk struct {
  19         Hostname string `json:"service_host"`
  20         Port     int    `json:"service_port"`
  21         SSL      bool   `json:"service_ssl_flag"`
  22         SvcType  string `json:"service_type"`
  23 }
  24
  25 func (this *KeepClient) DiscoverKeepServers() error {
  26         if prx := os.Getenv("ARVADOS_KEEP_PROXY"); prx != "" {
  27                 this.SetServiceRoots([]string{prx})
  28                 this.Using_proxy = true
  29                 return nil
  30         }
  31
  32         // Construct request of keep disk list
  33         var req *http.Request
  34         var err error
  35
  36         if req, err = http.NewRequest("GET", fmt.Sprintf("https://%s/arvados/v1/keep_services/accessible?format=json", this.ApiServer), nil); err != nil {
  37                 return err
  38         }
  39
  40         // Add api token header
  41         req.Header.Add("Authorization", fmt.Sprintf("OAuth2 %s", this.ApiToken))
  42         if this.External {
  43                 req.Header.Add("X-External-Client", "1")
  44         }
  45
  46         // Make the request
  47         var resp *http.Response
  48         if resp, err = this.Client.Do(req); err != nil {
  49                 return err
  50         }
  51
  52         if resp.StatusCode != http.StatusOK {
  53                 // fall back on keep disks
  54                 if req, err = http.NewRequest("GET", fmt.Sprintf("https://%s/arvados/v1/keep_disks", this.ApiServer), nil); err != nil {
  55                         return err
  56                 }
  57                 req.Header.Add("Authorization", fmt.Sprintf("OAuth2 %s", this.ApiToken))
  58                 if resp, err = this.Client.Do(req); err != nil {
  59                         return err
  60                 }
  61                 if resp.StatusCode != http.StatusOK {
  62                         return errors.New(resp.Status)
  63                 }
  64         }
  65
  66         type svcList struct {
  67                 Items []keepDisk `json:"items"`
  68         }
  69
  70         // Decode json reply
  71         dec := json.NewDecoder(resp.Body)
  72         var m svcList
  73         if err := dec.Decode(&m); err != nil {
  74                 return err
  75         }
  76
  77         listed := make(map[string]bool)
  78         service_roots := make([]string, 0, len(m.Items))
  79
  80         for _, element := range m.Items {
  81                 n := ""
  82
  83                 if element.SSL {
  84                         n = "s"
  85                 }
  86
  87                 // Construct server URL
  88                 url := fmt.Sprintf("http%s://%s:%d", n, element.Hostname, element.Port)
  89
  90                 // Skip duplicates
  91                 if !listed[url] {
  92                         listed[url] = true
  93                         service_roots = append(service_roots, url)
  94                 }
  95                 if element.SvcType == "proxy" {
  96                         this.Using_proxy = true
  97                 }
  98         }
  99
 100         this.SetServiceRoots(service_roots)
 101
 102         return nil
 103 }
 104
 105 func (this KeepClient) shuffledServiceRoots(hash string) (pseq []string) {
 106         // Build an ordering with which to query the Keep servers based on the
 107         // contents of the hash.  "hash" is a hex-encoded number at least 8
 108         // digits (32 bits) long
 109
 110         // seed used to calculate the next keep server from 'pool' to be added
 111         // to 'pseq'
 112         seed := hash
 113
 114         // Keep servers still to be added to the ordering
 115         service_roots := this.ServiceRoots()
 116         pool := make([]string, len(service_roots))
 117         copy(pool, service_roots)
 118
 119         // output probe sequence
 120         pseq = make([]string, 0, len(service_roots))
 121
 122         // iterate while there are servers left to be assigned
 123         for len(pool) > 0 {
 124
 125                 if len(seed) < 8 {
 126                         // ran out of digits in the seed
 127                         if len(pseq) < (len(hash) / 4) {
 128                                 // the number of servers added to the probe
 129                                 // sequence is less than the number of 4-digit
 130                                 // slices in 'hash' so refill the seed with the
 131                                 // last 4 digits.
 132                                 seed = hash[len(hash)-4:]
 133                         }
 134                         seed += hash
 135                 }
 136
 137                 // Take the next 8 digits (32 bytes) and interpret as an integer,
 138                 // then modulus with the size of the remaining pool to get the next
 139                 // selected server.
 140                 probe, _ := strconv.ParseUint(seed[0:8], 16, 32)
 141                 probe %= uint64(len(pool))
 142
 143                 // Append the selected server to the probe sequence and remove it
 144                 // from the pool.
 145                 pseq = append(pseq, pool[probe])
 146                 pool = append(pool[:probe], pool[probe+1:]...)
 147
 148                 // Remove the digits just used from the seed
 149                 seed = seed[8:]
 150         }
 151         return pseq
 152 }
 153
 154 type uploadStatus struct {
 155         err             error
 156         url             string
 157         statusCode      int
 158         replicas_stored int
 159         response        string
 160 }
 161
 162 func (this KeepClient) uploadToKeepServer(host string, hash string, body io.ReadCloser,
 163         upload_status chan<- uploadStatus, expectedLength int64) {
 164
 165         log.Printf("Uploading %s to %s", hash, host)
 166
 167         var req *http.Request
 168         var err error
 169         var url = fmt.Sprintf("%s/%s", host, hash)
 170         if req, err = http.NewRequest("PUT", url, nil); err != nil {
 171                 upload_status <- uploadStatus{err, url, 0, 0, ""}
 172                 body.Close()
 173                 return
 174         }
 175
 176         if expectedLength > 0 {
 177                 req.ContentLength = expectedLength
 178         }
 179
 180         req.Header.Add("Authorization", fmt.Sprintf("OAuth2 %s", this.ApiToken))
 181         req.Header.Add("Content-Type", "application/octet-stream")
 182
 183         if this.Using_proxy {
 184                 req.Header.Add(X_Keep_Desired_Replicas, fmt.Sprint(this.Want_replicas))
 185         }
 186
 187         req.Body = body
 188
 189         var resp *http.Response
 190         if resp, err = this.Client.Do(req); err != nil {
 191                 upload_status <- uploadStatus{err, url, 0, 0, ""}
 192                 body.Close()
 193                 return
 194         }
 195
 196         rep := 1
 197         if xr := resp.Header.Get(X_Keep_Replicas_Stored); xr != "" {
 198                 fmt.Sscanf(xr, "%d", &rep)
 199         }
 200
 201         respbody, err2 := ioutil.ReadAll(&io.LimitedReader{resp.Body, 4096})
 202         if err2 != nil && err2 != io.EOF {
 203                 upload_status <- uploadStatus{err2, url, resp.StatusCode, rep, string(respbody)}
 204                 return
 205         }
 206
 207         locator := strings.TrimSpace(string(respbody))
 208
 209         if resp.StatusCode == http.StatusOK {
 210                 upload_status <- uploadStatus{nil, url, resp.StatusCode, rep, locator}
 211         } else {
 212                 upload_status <- uploadStatus{errors.New(resp.Status), url, resp.StatusCode, rep, locator}
 213         }
 214 }
 215
 216 func (this KeepClient) putReplicas(
 217         hash string,
 218         tr *streamer.AsyncStream,
 219         expectedLength int64) (locator string, replicas int, err error) {
 220
 221         // Calculate the ordering for uploading to servers
 222         sv := this.shuffledServiceRoots(hash)
 223
 224         // The next server to try contacting
 225         next_server := 0
 226
 227         // The number of active writers
 228         active := 0
 229
 230         // Used to communicate status from the upload goroutines
 231         upload_status := make(chan uploadStatus)
 232         defer close(upload_status)
 233
 234         // Desired number of replicas
 235
 236         remaining_replicas := this.Want_replicas
 237
 238         for remaining_replicas > 0 {
 239                 for active < remaining_replicas {
 240                         // Start some upload requests
 241                         if next_server < len(sv) {
 242                                 go this.uploadToKeepServer(sv[next_server], hash, tr.MakeStreamReader(), upload_status, expectedLength)
 243                                 next_server += 1
 244                                 active += 1
 245                         } else {
 246                                 if active == 0 {
 247                                         return locator, (this.Want_replicas - remaining_replicas), InsufficientReplicasError
 248                                 } else {
 249                                         break
 250                                 }
 251                         }
 252                 }
 253
 254                 // Now wait for something to happen.
 255                 status := <-upload_status
 256                 if status.statusCode == 200 {
 257                         // good news!
 258                         remaining_replicas -= status.replicas_stored
 259                         locator = status.response
 260                 } else {
 261                         // writing to keep server failed for some reason
 262                         log.Printf("Keep server put to %v failed with '%v'",
 263                                 status.url, status.err)
 264                 }
 265                 active -= 1
 266                 log.Printf("Upload to %v status code: %v remaining replicas: %v active: %v", status.url, status.statusCode, remaining_replicas, active)
 267         }
 268
 269         return locator, this.Want_replicas, nil
 270 }