78 lines
1.8 KiB
Go
78 lines
1.8 KiB
Go
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package logical
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import (
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"encoding/json"
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"strings"
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)
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// WALPrefix is the prefix within Storage where WAL entries will be written.
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const WALPrefix = "wal/"
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// PutWAL writes some data to the WAL.
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//
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// Data within the WAL that is uncommitted (CommitWAL hasn't be called)
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// will be given to the rollback callback when an rollback operation is
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// received, allowing the backend to clean up some partial states.
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//
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// The data must be JSON encodable.
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//
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// This returns a unique ID that can be used to reference this WAL data.
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// WAL data cannot be modified. You can only add to the WAL and commit existing
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// WAL entries.
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func PutWAL(s Storage, data interface{}) (string, error) {
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value, err := json.Marshal(data)
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if err != nil {
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return "", err
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}
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id, err := UUID()
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if err != nil {
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return "", err
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}
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return id, s.Put(&StorageEntry{
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Key: WALPrefix + id,
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Value: value,
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})
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}
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// GetWAL reads a specific entry from the WAL. If the entry doesn't exist,
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// then nil value is returned.
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func GetWAL(s Storage, id string) (interface{}, error) {
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entry, err := s.Get(WALPrefix + id)
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if err != nil {
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return nil, err
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}
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if entry == nil {
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return nil, nil
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}
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var result interface{}
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if err := json.Unmarshal(entry.Value, &result); err != nil {
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return nil, err
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}
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return result, nil
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}
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// DeleteWAL commits the WAL entry with the given ID. Once comitted,
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// it is assumed that the operation was a success and doesn't need to
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// be rolled back.
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func DeleteWAL(s Storage, id string) error {
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return s.Delete(WALPrefix + id)
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}
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// ListWAL lists all the entries in the WAL.
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func ListWAL(s Storage) ([]string, error) {
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keys, err := s.List(WALPrefix)
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if err != nil {
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return nil, err
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}
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for i, k := range keys {
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keys[i] = strings.TrimPrefix(k, WALPrefix)
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}
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return keys, nil
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}
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