minio/vendor/gopkg.in/olivere/elastic.v3/reindexer.go

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// Copyright 2012-2015 Oliver Eilhard. All rights reserved.
// Use of this source code is governed by a MIT-license.
// See http://olivere.mit-license.org/license.txt for details.
package elastic
import (
"encoding/json"
"errors"
)
// Reindexer simplifies the process of reindexing an index. You typically
// reindex a source index to a target index. However, you can also specify
// a query that filters out documents from the source index before bulk
// indexing them into the target index. The caller may also specify a
// different client for the target, e.g. when copying indices from one
// Elasticsearch cluster to another.
//
// Internally, the Reindex users a scan and scroll operation on the source
// index and bulk indexing to push data into the target index.
//
// By default the reindexer fetches the _source, _parent, and _routing
// attributes from the source index, using the provided CopyToTargetIndex
// will copy those attributes into the destinationIndex.
// This behaviour can be overridden by setting the ScanFields and providing a
// custom ReindexerFunc.
//
// The caller is responsible for setting up and/or clearing the target index
// before starting the reindex process.
//
// See http://www.elastic.co/guide/en/elasticsearch/guide/current/reindex.html
// for more information about reindexing.
type Reindexer struct {
sourceClient, targetClient *Client
sourceIndex string
query Query
scanFields []string
bulkSize int
size int
scroll string
reindexerFunc ReindexerFunc
progress ReindexerProgressFunc
statsOnly bool
}
// A ReindexerFunc receives each hit from the sourceIndex.
// It can choose to add any number of BulkableRequests to the bulkService.
type ReindexerFunc func(hit *SearchHit, bulkService *BulkService) error
// CopyToTargetIndex returns a ReindexerFunc that copies the SearchHit's
// _source, _parent, and _routing attributes into the targetIndex
func CopyToTargetIndex(targetIndex string) ReindexerFunc {
return func(hit *SearchHit, bulkService *BulkService) error {
// TODO(oe) Do we need to deserialize here?
source := make(map[string]interface{})
if err := json.Unmarshal(*hit.Source, &source); err != nil {
return err
}
req := NewBulkIndexRequest().Index(targetIndex).Type(hit.Type).Id(hit.Id).Doc(source)
if hit.Parent != "" {
req = req.Parent(hit.Parent)
}
if hit.Routing != "" {
req = req.Routing(hit.Routing)
}
bulkService.Add(req)
return nil
}
}
// ReindexerProgressFunc is a callback that can be used with Reindexer
// to report progress while reindexing data.
type ReindexerProgressFunc func(current, total int64)
// ReindexerResponse is returned from the Do func in a Reindexer.
// By default, it returns the number of succeeded and failed bulk operations.
// To return details about all failed items, set StatsOnly to false in
// Reindexer.
type ReindexerResponse struct {
Success int64
Failed int64
Errors []*BulkResponseItem
}
// NewReindexer returns a new Reindexer.
func NewReindexer(client *Client, source string, reindexerFunc ReindexerFunc) *Reindexer {
return &Reindexer{
sourceClient: client,
sourceIndex: source,
reindexerFunc: reindexerFunc,
statsOnly: true,
}
}
// TargetClient specifies a different client for the target. This is
// necessary when the target index is in a different Elasticsearch cluster.
// By default, the source and target clients are the same.
func (ix *Reindexer) TargetClient(c *Client) *Reindexer {
ix.targetClient = c
return ix
}
// Query specifies the query to apply to the source. It filters out those
// documents to be indexed into target. A nil query does not filter out any
// documents.
func (ix *Reindexer) Query(q Query) *Reindexer {
ix.query = q
return ix
}
// ScanFields specifies the fields the scan query should load.
// The default fields are _source, _parent, _routing.
func (ix *Reindexer) ScanFields(scanFields ...string) *Reindexer {
ix.scanFields = scanFields
return ix
}
// BulkSize returns the number of documents to send to Elasticsearch per chunk.
// The default is 500.
func (ix *Reindexer) BulkSize(bulkSize int) *Reindexer {
ix.bulkSize = bulkSize
return ix
}
// Size is the number of results to return per shard, not per request.
// So a size of 10 which hits 5 shards will return a maximum of 50 results
// per scan request.
func (ix *Reindexer) Size(size int) *Reindexer {
ix.size = size
return ix
}
// Scroll specifies for how long the scroll operation on the source index
// should be maintained. The default is 5m.
func (ix *Reindexer) Scroll(timeout string) *Reindexer {
ix.scroll = timeout
return ix
}
// Progress indicates a callback that will be called while indexing.
func (ix *Reindexer) Progress(f ReindexerProgressFunc) *Reindexer {
ix.progress = f
return ix
}
// StatsOnly indicates whether the Do method should return details e.g. about
// the documents that failed while indexing. It is true by default, i.e. only
// the number of documents that succeeded/failed are returned. Set to false
// if you want all the details.
func (ix *Reindexer) StatsOnly(statsOnly bool) *Reindexer {
ix.statsOnly = statsOnly
return ix
}
// Do starts the reindexing process.
func (ix *Reindexer) Do() (*ReindexerResponse, error) {
if ix.sourceClient == nil {
return nil, errors.New("no source client")
}
if ix.sourceIndex == "" {
return nil, errors.New("no source index")
}
if ix.targetClient == nil {
ix.targetClient = ix.sourceClient
}
if ix.scanFields == nil {
ix.scanFields = []string{"_source", "_parent", "_routing"}
}
if ix.bulkSize <= 0 {
ix.bulkSize = 500
}
if ix.scroll == "" {
ix.scroll = "5m"
}
// Count total to report progress (if necessary)
var err error
var current, total int64
if ix.progress != nil {
total, err = ix.count()
if err != nil {
return nil, err
}
}
// Prepare scan and scroll to iterate through the source index
scanner := ix.sourceClient.Scan(ix.sourceIndex).Scroll(ix.scroll).Fields(ix.scanFields...)
if ix.query != nil {
scanner = scanner.Query(ix.query)
}
if ix.size > 0 {
scanner = scanner.Size(ix.size)
}
cursor, err := scanner.Do()
bulk := ix.targetClient.Bulk()
ret := &ReindexerResponse{
Errors: make([]*BulkResponseItem, 0),
}
// Main loop iterates through the source index and bulk indexes into target.
for {
docs, err := cursor.Next()
if err == EOS {
break
}
if err != nil {
return ret, err
}
if docs.TotalHits() > 0 {
for _, hit := range docs.Hits.Hits {
if ix.progress != nil {
current++
ix.progress(current, total)
}
err := ix.reindexerFunc(hit, bulk)
if err != nil {
return ret, err
}
if bulk.NumberOfActions() >= ix.bulkSize {
bulk, err = ix.commit(bulk, ret)
if err != nil {
return ret, err
}
}
}
}
}
// Final flush
if bulk.NumberOfActions() > 0 {
bulk, err = ix.commit(bulk, ret)
if err != nil {
return ret, err
}
bulk = nil
}
return ret, nil
}
// count returns the number of documents in the source index.
// The query is taken into account, if specified.
func (ix *Reindexer) count() (int64, error) {
service := ix.sourceClient.Count(ix.sourceIndex)
if ix.query != nil {
service = service.Query(ix.query)
}
return service.Do()
}
// commit commits a bulk, updates the stats, and returns a fresh bulk service.
func (ix *Reindexer) commit(bulk *BulkService, ret *ReindexerResponse) (*BulkService, error) {
bres, err := bulk.Do()
if err != nil {
return nil, err
}
ret.Success += int64(len(bres.Succeeded()))
failed := bres.Failed()
ret.Failed += int64(len(failed))
if !ix.statsOnly {
ret.Errors = append(ret.Errors, failed...)
}
bulk = ix.targetClient.Bulk()
return bulk, nil
}