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