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