services/ws/session_v0.go

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