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 }
  21
  22 type event struct {
  23         LogID    uint64
  24         Received time.Time
  25         Serial   uint64
  26
  27         db     *sql.DB
  28         logRow *arvados.Log
  29         err    error
  30         mtx    sync.Mutex
  31 }
  32
  33 // Detail returns the database row corresponding to the event. It can
  34 // be called safely from multiple goroutines. Only one attempt will be
  35 // made. If the database row cannot be retrieved, Detail returns nil.
  36 func (e *event) Detail() *arvados.Log {
  37         e.mtx.Lock()
  38         defer e.mtx.Unlock()
  39         if e.logRow != nil || e.err != nil {
  40                 return e.logRow
  41         }
  42         var logRow arvados.Log
  43         var propYAML []byte
  44         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(
  45                 &logRow.ID,
  46                 &logRow.UUID,
  47                 &logRow.ObjectUUID,
  48                 &logRow.ObjectOwnerUUID,
  49                 &logRow.EventType,
  50                 &logRow.CreatedAt,
  51                 &propYAML)
  52         if e.err != nil {
  53                 log.Printf("retrieving log row %d: %s", e.LogID, e.err)
  54                 return nil
  55         }
  56         e.err = yaml.Unmarshal(propYAML, &logRow.Properties)
  57         if e.err != nil {
  58                 log.Printf("decoding yaml for log row %d: %s", e.LogID, e.err)
  59                 return nil
  60         }
  61         e.logRow = &logRow
  62         return e.logRow
  63 }