// Commit takes a storage transaction and writes any headers or indexes to make
// the transacted facts visible. A storage transaction is passed in to enable
// the writes to occur atomically which ensures consistency of the transacted
// facts.
func (p *Pipeline) Commit(tx storage.Tx) error {
var (
err error
log *dal.Log
)
// Write the remaining block of the segment.
if err = p.segment.Commit(tx); err != nil {
return err
}
// No new facts, remove the segment.
if p.segment.Count == 0 {
logrus.Debugf("pipeline: no facts written to %s, removing segment", p.Domain)
p.segment.Abort(tx)
return nil
}
logrus.Debugf("pipeline: %d facts written to %s", p.segment.Count, p.Domain)
// Compare and swap ID on domain's commit log.
if log, err = dal.GetLog(tx, p.Domain, commitLogName); err != nil {
return err
}
// Existing commit log, check if the head is the same.
if log != nil {
// TODO: determine path to handle conflicts.
if log.Head != nil && !uuid.Equal(*log.Head, *p.segment.Base) {
return ErrCommitConflict
}
} else {
log = &dal.Log{
Name: commitLogName,
Domain: p.Domain,
}
}
log.Head = p.segment.UUID
_, err = dal.SetLog(tx, p.Domain, log)
return err
}
// Init initializes the pipeline for the transaction.
func (p *Pipeline) Init(tx *Transaction) error {
// Get the commit log for this domain.
log, err := dal.GetLog(tx.Engine, p.Domain, commitLogName)
if err != nil {
return err
}
if log == nil {
log = &dal.Log{}
}
// Initialize new segment pointing to the head of the log.
p.segment = NewSegment(tx.Engine, p.Domain, tx.ID)
p.segment.Base = log.Head
p.segment.Next = log.Head
p.segment.Time = tx.StartTime
p.engine = tx.Engine
p.dedupe = !tx.options.AllowDuplicates
return nil
}