services/ws/event.go

   1 package main
   2
   3 import (
   4         "database/sql"
   5         "log"
   6         "sync"
   7         "time"
   8
   9         "git.curoverse.com/arvados.git/sdk/go/arvados"
  10         "github.com/ghodss/yaml"
  11 )
  12
  13 type eventSink interface {
  14         Channel() <-chan *event
  15         Stop()
  16 }
  17
  18 type eventSource interface {
  19         NewSink() eventSink
  20         DB() *sql.DB
  21 }
  22
  23 type event struct {
  24         LogID    uint64
  25         Received time.Time
  26         Serial   uint64
  27
  28         db     *sql.DB
  29         logRow *arvados.Log
  30         err    error
  31         mtx    sync.Mutex
  32 }
  33
  34 // Detail returns the database row corresponding to the event. It can
  35 // be called safely from multiple goroutines. Only one attempt will be
  36 // made. If the database row cannot be retrieved, Detail returns nil.
  37 func (e *event) Detail() *arvados.Log {
  38         e.mtx.Lock()
  39         defer e.mtx.Unlock()
  40         if e.logRow != nil || e.err != nil {
  41                 return e.logRow
  42         }
  43         var logRow arvados.Log
  44         var propYAML []byte
  45         e.err = e.db.QueryRow(`SELECT id, uuid, object_uuid, COALESCE(object_owner_uuid,''), COALESCE(event_type,''), created_at, properties FROM logs WHERE id = $1`, e.LogID).Scan(
  46                 &logRow.ID,
  47                 &logRow.UUID,
  48                 &logRow.ObjectUUID,
  49                 &logRow.ObjectOwnerUUID,
  50                 &logRow.EventType,
  51                 &logRow.CreatedAt,
  52                 &propYAML)
  53         if e.err != nil {
  54                 log.Printf("retrieving log row %d: %s", e.LogID, e.err)
  55                 return nil
  56         }
  57         e.err = yaml.Unmarshal(propYAML, &logRow.Properties)
  58         if e.err != nil {
  59                 log.Printf("decoding yaml for log row %d: %s", e.LogID, e.err)
  60                 return nil
  61         }
  62         e.logRow = &logRow
  63         return e.logRow
  64 }