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"}
  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         }
 101         if detail.Properties != nil && detail.Properties["text"] != nil {
 102                 msg["properties"] = detail.Properties
 103         } else {
 104                 msgProps := map[string]map[string]interface{}{}
 105                 for _, ak := range []string{"old_attributes", "new_attributes"} {
 106                         eventAttrs, ok := detail.Properties[ak].(map[string]interface{})
 107                         if !ok {
 108                                 continue
 109                         }
 110                         msgAttrs := map[string]interface{}{}
 111                         for _, k := range sendObjectAttributes {
 112                                 if v, ok := eventAttrs[k]; ok {
 113                                         msgAttrs[k] = v
 114                                 }
 115                         }
 116                         msgProps[ak] = msgAttrs
 117                 }
 118                 msg["properties"] = msgProps
 119         }
 120         return json.Marshal(msg)
 121 }
 122
 123 func (sess *v0session) Filter(e *event) bool {
 124         sess.mtx.Lock()
 125         defer sess.mtx.Unlock()
 126         for _, sub := range sess.subscriptions {
 127                 if sub.match(sess, e) {
 128                         return true
 129                 }
 130         }
 131         return false
 132 }
 133
 134 func (sub *v0subscribe) sendOldEvents(sess *v0session) {
 135         if sub.LastLogID == 0 {
 136                 return
 137         }
 138         sess.log.WithField("LastLogID", sub.LastLogID).Debug("getOldEvents")
 139         // Here we do a "select id" query and queue an event for every
 140         // log since the given ID, then use (*event)Detail() to
 141         // retrieve the whole row and decide whether to send it. This
 142         // approach is very inefficient if the subscriber asks for
 143         // last_log_id==1, even if the filters end up matching very
 144         // few events.
 145         //
 146         // To mitigate this, filter on "created > 10 minutes ago" when
 147         // retrieving the list of old event IDs to consider.
 148         rows, err := sess.db.Query(
 149                 `SELECT id FROM logs WHERE id > $1 AND created_at > $2 ORDER BY id`,
 150                 sub.LastLogID,
 151                 time.Now().UTC().Add(-10*time.Minute).Format(time.RFC3339Nano))
 152         if err != nil {
 153                 sess.log.WithError(err).Error("db.Query failed")
 154                 return
 155         }
 156         for rows.Next() {
 157                 var id uint64
 158                 err := rows.Scan(&id)
 159                 if err != nil {
 160                         sess.log.WithError(err).Error("row Scan failed")
 161                         continue
 162                 }
 163                 for len(sess.sendq)*2 > cap(sess.sendq) {
 164                         // Ugly... but if we fill up the whole client
 165                         // queue with a backlog of old events, a
 166                         // single new event will overflow it and
 167                         // terminate the connection, and then the
 168                         // client will probably reconnect and do the
 169                         // same thing all over again.
 170                         time.Sleep(100 * time.Millisecond)
 171                 }
 172                 now := time.Now()
 173                 e := &event{
 174                         LogID:    id,
 175                         Received: now,
 176                         Ready:    now,
 177                         db:       sess.db,
 178                 }
 179                 if sub.match(sess, e) {
 180                         select {
 181                         case sess.sendq <- e:
 182                         case <-sess.ws.Request().Context().Done():
 183                                 return
 184                         }
 185                 }
 186         }
 187         if err := rows.Err(); err != nil {
 188                 sess.log.WithError(err).Error("db.Query failed")
 189         }
 190 }
 191
 192 type v0subscribe struct {
 193         Method    string
 194         Filters   []v0filter
 195         LastLogID int64 `json:"last_log_id"`
 196
 197         funcs []func(*event) bool
 198 }
 199
 200 type v0filter [3]interface{}
 201
 202 func (sub *v0subscribe) match(sess *v0session, e *event) bool {
 203         log := sess.log.WithField("LogID", e.LogID)
 204         detail := e.Detail()
 205         if detail == nil {
 206                 log.Error("match failed, no detail")
 207                 return false
 208         }
 209         log = log.WithField("funcs", len(sub.funcs))
 210         for i, f := range sub.funcs {
 211                 if !f(e) {
 212                         log.WithField("func", i).Debug("match failed")
 213                         return false
 214                 }
 215         }
 216         log.Debug("match passed")
 217         return true
 218 }
 219
 220 func (sub *v0subscribe) prepare(sess *v0session) {
 221         for _, f := range sub.Filters {
 222                 if len(f) != 3 {
 223                         continue
 224                 }
 225                 if col, ok := f[0].(string); ok && col == "event_type" {
 226                         op, ok := f[1].(string)
 227                         if !ok || op != "in" {
 228                                 continue
 229                         }
 230                         arr, ok := f[2].([]interface{})
 231                         if !ok {
 232                                 continue
 233                         }
 234                         var strs []string
 235                         for _, s := range arr {
 236                                 if s, ok := s.(string); ok {
 237                                         strs = append(strs, s)
 238                                 }
 239                         }
 240                         sub.funcs = append(sub.funcs, func(e *event) bool {
 241                                 for _, s := range strs {
 242                                         if s == e.Detail().EventType {
 243                                                 return true
 244                                         }
 245                                 }
 246                                 return false
 247                         })
 248                 } else if ok && col == "created_at" {
 249                         op, ok := f[1].(string)
 250                         if !ok {
 251                                 continue
 252                         }
 253                         tstr, ok := f[2].(string)
 254                         if !ok {
 255                                 continue
 256                         }
 257                         t, err := time.Parse(time.RFC3339Nano, tstr)
 258                         if err != nil {
 259                                 sess.log.WithField("data", tstr).WithError(err).Info("time.Parse failed")
 260                                 continue
 261                         }
 262                         var fn func(*event) bool
 263                         switch op {
 264                         case ">=":
 265                                 fn = func(e *event) bool {
 266                                         return !e.Detail().CreatedAt.Before(t)
 267                                 }
 268                         case "<=":
 269                                 fn = func(e *event) bool {
 270                                         return !e.Detail().CreatedAt.After(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.Before(t)
 279                                 }
 280                         case "=":
 281                                 fn = func(e *event) bool {
 282                                         return e.Detail().CreatedAt.Equal(t)
 283                                 }
 284                         default:
 285                                 sess.log.WithField("operator", op).Info("bogus operator")
 286                                 continue
 287                         }
 288                         sub.funcs = append(sub.funcs, fn)
 289                 }
 290         }
 291 }