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