services/ws/session_v0.go

   1 // Copyright (C) The Arvados Authors. All rights reserved.
   2 //
   3 // SPDX-License-Identifier: AGPL-3.0
   4
   5 package ws
   6
   7 import (
   8         "database/sql"
   9         "encoding/json"
  10         "errors"
  11         "reflect"
  12         "sync"
  13         "sync/atomic"
  14         "time"
  15
  16         "git.arvados.org/arvados.git/sdk/go/arvados"
  17         "git.arvados.org/arvados.git/sdk/go/ctxlog"
  18         "github.com/sirupsen/logrus"
  19 )
  20
  21 var (
  22         errQueueFull   = errors.New("client queue full")
  23         errFrameTooBig = errors.New("frame too big")
  24
  25         // Send clients only these keys from the
  26         // log.properties.old_attributes and
  27         // log.properties.new_attributes hashes.
  28         sendObjectAttributes = []string{
  29                 "is_trashed",
  30                 "name",
  31                 "owner_uuid",
  32                 "portable_data_hash",
  33                 "state",
  34         }
  35
  36         v0subscribeOK   = []byte(`{"status":200}`)
  37         v0subscribeFail = []byte(`{"status":400}`)
  38 )
  39
  40 type v0session struct {
  41         ac            *arvados.Client
  42         ws            wsConn
  43         sendq         chan<- interface{}
  44         db            *sql.DB
  45         permChecker   permChecker
  46         subscriptions []v0subscribe
  47         lastMsgID     uint64
  48         log           logrus.FieldLogger
  49         mtx           sync.Mutex
  50         setupOnce     sync.Once
  51 }
  52
  53 // newSessionV0 returns a v0 session: a partial port of the Rails/puma
  54 // implementation, with just enough functionality to support Workbench
  55 // and arv-mount.
  56 func newSessionV0(ws wsConn, sendq chan<- interface{}, db *sql.DB, pc permChecker, ac *arvados.Client) (session, error) {
  57         sess := &v0session{
  58                 sendq:       sendq,
  59                 ws:          ws,
  60                 db:          db,
  61                 ac:          ac,
  62                 permChecker: pc,
  63                 log:         ctxlog.FromContext(ws.Request().Context()),
  64         }
  65
  66         err := ws.Request().ParseForm()
  67         if err != nil {
  68                 sess.log.WithError(err).Error("ParseForm failed")
  69                 return nil, err
  70         }
  71         token := ws.Request().Form.Get("api_token")
  72         sess.permChecker.SetToken(token)
  73         sess.log.WithField("token", token).Debug("set token")
  74
  75         return sess, nil
  76 }
  77
  78 func (sess *v0session) Receive(buf []byte) error {
  79         var sub v0subscribe
  80         if err := json.Unmarshal(buf, &sub); err != nil {
  81                 sess.log.WithError(err).Info("invalid message from client")
  82         } else if sub.Method == "subscribe" {
  83                 sub.prepare(sess)
  84                 sess.log.WithField("sub", sub).Debug("sub prepared")
  85                 sess.sendq <- v0subscribeOK
  86                 sess.mtx.Lock()
  87                 sess.subscriptions = append(sess.subscriptions, sub)
  88                 sess.mtx.Unlock()
  89                 sub.sendOldEvents(sess)
  90                 return nil
  91         } else if sub.Method == "unsubscribe" {
  92                 sess.mtx.Lock()
  93                 found := false
  94                 for i, s := range sess.subscriptions {
  95                         if !reflect.DeepEqual(s.Filters, sub.Filters) {
  96                                 continue
  97                         }
  98                         copy(sess.subscriptions[i:], sess.subscriptions[i+1:])
  99                         sess.subscriptions = sess.subscriptions[:len(sess.subscriptions)-1]
 100                         found = true
 101                         break
 102                 }
 103                 sess.mtx.Unlock()
 104                 sess.log.WithField("sub", sub).WithField("found", found).Debug("unsubscribe")
 105                 if found {
 106                         sess.sendq <- v0subscribeOK
 107                         return nil
 108                 }
 109         } else {
 110                 sess.log.WithField("Method", sub.Method).Info("unknown method")
 111         }
 112         sess.sendq <- v0subscribeFail
 113         return nil
 114 }
 115
 116 func (sess *v0session) EventMessage(e *event) ([]byte, error) {
 117         detail := e.Detail()
 118         if detail == nil {
 119                 return nil, nil
 120         }
 121
 122         var permTarget string
 123         if detail.EventType == "delete" {
 124                 // It's pointless to check permission by reading
 125                 // ObjectUUID if it has just been deleted, but if the
 126                 // client has permission on the parent project then
 127                 // it's OK to send the event.
 128                 permTarget = detail.ObjectOwnerUUID
 129         } else {
 130                 permTarget = detail.ObjectUUID
 131         }
 132         ok, err := sess.permChecker.Check(sess.ws.Request().Context(), permTarget)
 133         if err != nil || !ok {
 134                 return nil, err
 135         }
 136
 137         kind, _ := sess.ac.KindForUUID(detail.ObjectUUID)
 138         msg := map[string]interface{}{
 139                 "msgID":             atomic.AddUint64(&sess.lastMsgID, 1),
 140                 "id":                detail.ID,
 141                 "uuid":              detail.UUID,
 142                 "object_uuid":       detail.ObjectUUID,
 143                 "object_owner_uuid": detail.ObjectOwnerUUID,
 144                 "object_kind":       kind,
 145                 "event_type":        detail.EventType,
 146                 "event_at":          detail.EventAt,
 147         }
 148         if detail.Properties != nil && detail.Properties["text"] != nil {
 149                 msg["properties"] = detail.Properties
 150         } else {
 151                 msgProps := map[string]map[string]interface{}{}
 152                 for _, ak := range []string{"old_attributes", "new_attributes"} {
 153                         eventAttrs, ok := detail.Properties[ak].(map[string]interface{})
 154                         if !ok {
 155                                 continue
 156                         }
 157                         msgAttrs := map[string]interface{}{}
 158                         for _, k := range sendObjectAttributes {
 159                                 if v, ok := eventAttrs[k]; ok {
 160                                         msgAttrs[k] = v
 161                                 }
 162                         }
 163                         msgProps[ak] = msgAttrs
 164                 }
 165                 msg["properties"] = msgProps
 166         }
 167         return json.Marshal(msg)
 168 }
 169
 170 func (sess *v0session) Filter(e *event) bool {
 171         sess.mtx.Lock()
 172         defer sess.mtx.Unlock()
 173         for _, sub := range sess.subscriptions {
 174                 if sub.match(sess, e) {
 175                         return true
 176                 }
 177         }
 178         return false
 179 }
 180
 181 func (sub *v0subscribe) sendOldEvents(sess *v0session) {
 182         if sub.LastLogID == 0 {
 183                 return
 184         }
 185         sess.log.WithField("LastLogID", sub.LastLogID).Debug("sendOldEvents")
 186         // Here we do a "select id" query and queue an event for every
 187         // log since the given ID, then use (*event)Detail() to
 188         // retrieve the whole row and decide whether to send it. This
 189         // approach is very inefficient if the subscriber asks for
 190         // last_log_id==1, even if the filters end up matching very
 191         // few events.
 192         //
 193         // To mitigate this, filter on "created > 10 minutes ago" when
 194         // retrieving the list of old event IDs to consider.
 195         rows, err := sess.db.Query(
 196                 `SELECT id FROM logs WHERE id > $1 AND created_at > $2 ORDER BY id`,
 197                 sub.LastLogID,
 198                 time.Now().UTC().Add(-10*time.Minute).Format(time.RFC3339Nano))
 199         if err != nil {
 200                 sess.log.WithError(err).Error("sendOldEvents db.Query failed")
 201                 return
 202         }
 203
 204         var ids []int64
 205         for rows.Next() {
 206                 var id int64
 207                 err := rows.Scan(&id)
 208                 if err != nil {
 209                         sess.log.WithError(err).Error("sendOldEvents row Scan failed")
 210                         continue
 211                 }
 212                 ids = append(ids, id)
 213         }
 214         if err := rows.Err(); err != nil {
 215                 sess.log.WithError(err).Error("sendOldEvents db.Query failed")
 216         }
 217         rows.Close()
 218
 219         for _, id := range ids {
 220                 for len(sess.sendq)*2 > cap(sess.sendq) {
 221                         // Ugly... but if we fill up the whole client
 222                         // queue with a backlog of old events, a
 223                         // single new event will overflow it and
 224                         // terminate the connection, and then the
 225                         // client will probably reconnect and do the
 226                         // same thing all over again.
 227                         time.Sleep(100 * time.Millisecond)
 228                         if sess.ws.Request().Context().Err() != nil {
 229                                 // Session terminated while we were sleeping
 230                                 return
 231                         }
 232                 }
 233                 now := time.Now()
 234                 e := &event{
 235                         LogID:    id,
 236                         Received: now,
 237                         Ready:    now,
 238                         db:       sess.db,
 239                 }
 240                 if sub.match(sess, e) {
 241                         select {
 242                         case sess.sendq <- e:
 243                         case <-sess.ws.Request().Context().Done():
 244                                 return
 245                         }
 246                 }
 247         }
 248 }
 249
 250 type v0subscribe struct {
 251         Method    string
 252         Filters   []v0filter
 253         LastLogID int64 `json:"last_log_id"`
 254
 255         funcs []func(*event) bool
 256 }
 257
 258 type v0filter [3]interface{}
 259
 260 func (sub *v0subscribe) match(sess *v0session, e *event) bool {
 261         log := sess.log.WithField("LogID", e.LogID)
 262         detail := e.Detail()
 263         if detail == nil {
 264                 log.Error("match failed, no detail")
 265                 return false
 266         }
 267         log = log.WithField("funcs", len(sub.funcs))
 268         for i, f := range sub.funcs {
 269                 if !f(e) {
 270                         log.WithField("func", i).Debug("match failed")
 271                         return false
 272                 }
 273         }
 274         log.Debug("match passed")
 275         return true
 276 }
 277
 278 func (sub *v0subscribe) prepare(sess *v0session) {
 279         for _, f := range sub.Filters {
 280                 if len(f) != 3 {
 281                         continue
 282                 }
 283                 if col, ok := f[0].(string); ok && col == "event_type" {
 284                         op, ok := f[1].(string)
 285                         if !ok || op != "in" {
 286                                 continue
 287                         }
 288                         arr, ok := f[2].([]interface{})
 289                         if !ok {
 290                                 continue
 291                         }
 292                         var strs []string
 293                         for _, s := range arr {
 294                                 if s, ok := s.(string); ok {
 295                                         strs = append(strs, s)
 296                                 }
 297                         }
 298                         sub.funcs = append(sub.funcs, func(e *event) bool {
 299                                 for _, s := range strs {
 300                                         if s == e.Detail().EventType {
 301                                                 return true
 302                                         }
 303                                 }
 304                                 return false
 305                         })
 306                 } else if ok && col == "created_at" {
 307                         op, ok := f[1].(string)
 308                         if !ok {
 309                                 continue
 310                         }
 311                         tstr, ok := f[2].(string)
 312                         if !ok {
 313                                 continue
 314                         }
 315                         t, err := time.Parse(time.RFC3339Nano, tstr)
 316                         if err != nil {
 317                                 sess.log.WithField("data", tstr).WithError(err).Info("time.Parse failed")
 318                                 continue
 319                         }
 320                         var fn func(*event) bool
 321                         switch op {
 322                         case ">=":
 323                                 fn = func(e *event) bool {
 324                                         return !e.Detail().CreatedAt.Before(t)
 325                                 }
 326                         case "<=":
 327                                 fn = func(e *event) bool {
 328                                         return !e.Detail().CreatedAt.After(t)
 329                                 }
 330                         case ">":
 331                                 fn = func(e *event) bool {
 332                                         return e.Detail().CreatedAt.After(t)
 333                                 }
 334                         case "<":
 335                                 fn = func(e *event) bool {
 336                                         return e.Detail().CreatedAt.Before(t)
 337                                 }
 338                         case "=":
 339                                 fn = func(e *event) bool {
 340                                         return e.Detail().CreatedAt.Equal(t)
 341                                 }
 342                         default:
 343                                 sess.log.WithField("operator", op).Info("bogus operator")
 344                                 continue
 345                         }
 346                         sub.funcs = append(sub.funcs, fn)
 347                 }
 348         }
 349 }