gitea/vendor/github.com/ethantkoenig/rupture/metadata.go

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2018-02-05 19:29:17 +01:00
package rupture
import (
"encoding/json"
"io/ioutil"
"os"
"path/filepath"
)
const metaFilename = "rupture_meta.json"
func indexMetadataPath(dir string) string {
return filepath.Join(dir, metaFilename)
}
// IndexMetadata contains metadata about a bleve index.
type IndexMetadata struct {
// The version of the data in the index. This can be useful for tracking
// schema changes or data migrations.
Version int `json:"version"`
}
// in addition to the user-exposed metadata, we keep additional, internal-only
// metadata for sharded indices.
const shardedMetadataFilename = "rupture_sharded_meta.json"
func shardedIndexMetadataPath(dir string) string {
return filepath.Join(dir, shardedMetadataFilename)
}
type shardedIndexMetadata struct {
NumShards int `json:"num_shards"`
}
func readJSON(path string, meta interface{}) error {
metaBytes, err := ioutil.ReadFile(path)
if err != nil {
return err
}
return json.Unmarshal(metaBytes, meta)
}
func writeJSON(path string, meta interface{}) error {
metaBytes, err := json.Marshal(meta)
if err != nil {
return err
}
return ioutil.WriteFile(path, metaBytes, 0666)
}
// ReadIndexMetadata returns the metadata for the index at the specified path.
// If no such index metadata exists, an empty metadata and a nil error are
// returned.
func ReadIndexMetadata(path string) (*IndexMetadata, error) {
meta := &IndexMetadata{}
metaPath := indexMetadataPath(path)
if _, err := os.Stat(metaPath); os.IsNotExist(err) {
return meta, nil
} else if err != nil {
return nil, err
}
return meta, readJSON(metaPath, meta)
}
// WriteIndexMetadata writes metadata for the index at the specified path.
func WriteIndexMetadata(path string, meta *IndexMetadata) error {
return writeJSON(indexMetadataPath(path), meta)
}