func (bucket CouchbaseBucketGoCB) WriteCas(k string, flags int, exp int, cas uint64, v interface{}, opt sgbucket.WriteOptions) (casOut uint64, err error) {
bucket.singleOps <- struct{}{}
defer func() {
<-bucket.singleOps
}()
// we only support the sgbucket.Raw WriteOption at this point
if opt != sgbucket.Raw {
LogPanic("WriteOption must be sgbucket.Raw")
}
// also, flags must be 0, since that is not supported by gocb
if flags != 0 {
LogPanic("flags must be 0")
}
worker := func() (shouldRetry bool, err error, value interface{}) {
if cas == 0 {
// Try to insert the value into the bucket
gocbExpvars.Add("WriteCas_Insert", 1)
newCas, err := bucket.Bucket.Insert(k, v, uint32(exp))
shouldRetry = isRecoverableGoCBError(err)
return shouldRetry, err, uint64(newCas)
}
// Otherwise, replace existing value
gocbExpvars.Add("WriteCas_Replace", 1)
newCas, err := bucket.Bucket.Replace(k, v, gocb.Cas(cas), uint32(exp))
shouldRetry = isRecoverableGoCBError(err)
return shouldRetry, err, uint64(newCas)
}
sleeper := CreateDoublingSleeperFunc(
bucket.spec.MaxNumRetries,
bucket.spec.InitialRetrySleepTimeMS,
)
// Kick off retry loop
description := fmt.Sprintf("WriteCas with key %v", k)
err, result := RetryLoop(description, worker, sleeper)
// If the retry loop returned a nil result, set to 0 to prevent type assertion on nil error
if result == nil {
result = uint64(0)
}
// Type assertion of result
cas, ok := result.(uint64)
if !ok {
return 0, fmt.Errorf("Error doing type assertion of %v into a uint64, Key: %v", result, k)
}
return cas, err
}
func (bucket CouchbaseBucketGoCB) processBulkSetEntriesBatch(entries []*sgbucket.BulkSetEntry) (error, []*sgbucket.BulkSetEntry) {
retryEntries := []*sgbucket.BulkSetEntry{}
var items []gocb.BulkOp
for _, entry := range entries {
switch entry.Cas {
case 0:
// if no CAS val, treat it as an insert (similar to WriteCas())
item := &gocb.InsertOp{
Key: entry.Key,
Value: entry.Value,
}
items = append(items, item)
default:
// otherwise, treat it as a replace
item := &gocb.ReplaceOp{
Key: entry.Key,
Value: entry.Value,
Cas: gocb.Cas(entry.Cas),
}
items = append(items, item)
}
}
// Do the underlying bulk operation
if err := bucket.Do(items); err != nil {
return err, retryEntries
}
for index, item := range items {
entry := entries[index]
switch item := item.(type) {
case *gocb.InsertOp:
entry.Cas = uint64(item.Cas)
entry.Error = item.Err
if item.Err != nil && isRecoverableGoCBError(item.Err) {
retryEntries = append(retryEntries, entry)
}
case *gocb.ReplaceOp:
entry.Cas = uint64(item.Cas)
entry.Error = item.Err
if item.Err != nil && isRecoverableGoCBError(item.Err) {
retryEntries = append(retryEntries, entry)
}
}
}
return nil, retryEntries
}
func (bucket CouchbaseBucketGoCB) Update(k string, exp int, callback sgbucket.UpdateFunc) error {
bucket.singleOps <- struct{}{}
defer func() {
<-bucket.singleOps
}()
maxCasRetries := 100000 // prevent infinite loop
for i := 0; i < maxCasRetries; i++ {
var value interface{}
var err error
// Load the existing value.
// NOTE: ignore error and assume it's a "key not found" error. If it's a more
// serious error, it will probably recur when calling other ops below
gocbExpvars.Add("Update_Get", 1)
cas, _ := bucket.Get(k, &value)
var callbackParam []byte
if value != nil {
callbackParam = value.([]byte)
}
// Invoke callback to get updated value
value, err = callback(callbackParam)
if err != nil {
return err
}
if cas == 0 {
// If the Get fails, the cas will be 0 and so call Insert().
// If we get an error on the insert, due to a race, this will
// go back through the cas loop
gocbExpvars.Add("Update_Insert", 1)
_, err = bucket.Bucket.Insert(k, value, uint32(exp))
} else {
if value == nil {
// In order to match the go-couchbase bucket behavior, if the
// callback returns nil, we delete the doc
gocbExpvars.Add("Update_Remove", 1)
_, err = bucket.Bucket.Remove(k, gocb.Cas(cas))
} else {
// Otherwise, attempt to do a replace. won't succeed if
// updated underneath us
gocbExpvars.Add("Update_Replace", 1)
_, err = bucket.Bucket.Replace(k, value, gocb.Cas(cas), uint32(exp))
}
}
// If there was no error, we're done
if err == nil {
return nil
}
}
return fmt.Errorf("Failed to update after %v CAS attempts", maxCasRetries)
}