forgejo/modules/indexer/issues/elastic_search.go
wxiaoguang 6f9c278559
Rewrite queue (#24505)
# ⚠️ Breaking

Many deprecated queue config options are removed (actually, they should
have been removed in 1.18/1.19).

If you see the fatal message when starting Gitea: "Please update your
app.ini to remove deprecated config options", please follow the error
messages to remove these options from your app.ini.

Example:

```
2023/05/06 19:39:22 [E] Removed queue option: `[indexer].ISSUE_INDEXER_QUEUE_TYPE`. Use new options in `[queue.issue_indexer]`
2023/05/06 19:39:22 [E] Removed queue option: `[indexer].UPDATE_BUFFER_LEN`. Use new options in `[queue.issue_indexer]`
2023/05/06 19:39:22 [F] Please update your app.ini to remove deprecated config options
```

Many options in `[queue]` are are dropped, including:
`WRAP_IF_NECESSARY`, `MAX_ATTEMPTS`, `TIMEOUT`, `WORKERS`,
`BLOCK_TIMEOUT`, `BOOST_TIMEOUT`, `BOOST_WORKERS`, they can be removed
from app.ini.

# The problem

The old queue package has some legacy problems:

* complexity: I doubt few people could tell how it works.
* maintainability: Too many channels and mutex/cond are mixed together,
too many different structs/interfaces depends each other.
* stability: due to the complexity & maintainability, sometimes there
are strange bugs and difficult to debug, and some code doesn't have test
(indeed some code is difficult to test because a lot of things are mixed
together).
* general applicability: although it is called "queue", its behavior is
not a well-known queue.
* scalability: it doesn't seem easy to make it work with a cluster
without breaking its behaviors.

It came from some very old code to "avoid breaking", however, its
technical debt is too heavy now. It's a good time to introduce a better
"queue" package.

# The new queue package

It keeps using old config and concept as much as possible.

* It only contains two major kinds of concepts:
    * The "base queue": channel, levelqueue, redis
* They have the same abstraction, the same interface, and they are
tested by the same testing code.
* The "WokerPoolQueue", it uses the "base queue" to provide "worker
pool" function, calls the "handler" to process the data in the base
queue.
* The new code doesn't do "PushBack"
* Think about a queue with many workers, the "PushBack" can't guarantee
the order for re-queued unhandled items, so in new code it just does
"normal push"
* The new code doesn't do "pause/resume"
* The "pause/resume" was designed to handle some handler's failure: eg:
document indexer (elasticsearch) is down
* If a queue is paused for long time, either the producers blocks or the
new items are dropped.
* The new code doesn't do such "pause/resume" trick, it's not a common
queue's behavior and it doesn't help much.
* If there are unhandled items, the "push" function just blocks for a
few seconds and then re-queue them and retry.
* The new code doesn't do "worker booster"
* Gitea's queue's handlers are light functions, the cost is only the
go-routine, so it doesn't make sense to "boost" them.
* The new code only use "max worker number" to limit the concurrent
workers.
* The new "Push" never blocks forever
* Instead of creating more and more blocking goroutines, return an error
is more friendly to the server and to the end user.

There are more details in code comments: eg: the "Flush" problem, the
strange "code.index" hanging problem, the "immediate" queue problem.

Almost ready for review.

TODO:

* [x] add some necessary comments during review
* [x] add some more tests if necessary
* [x] update documents and config options
* [x] test max worker / active worker
* [x] re-run the CI tasks to see whether any test is flaky
* [x] improve the `handleOldLengthConfiguration` to provide more
friendly messages
* [x] fine tune default config values (eg: length?)

## Code coverage:

![image](https://user-images.githubusercontent.com/2114189/236620635-55576955-f95d-4810-b12f-879026a3afdf.png)
2023-05-08 19:49:59 +08:00

300 lines
6.6 KiB
Go

// Copyright 2019 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package issues
import (
"context"
"errors"
"fmt"
"net"
"strconv"
"sync"
"time"
"code.gitea.io/gitea/modules/graceful"
"code.gitea.io/gitea/modules/log"
"github.com/olivere/elastic/v7"
)
var _ Indexer = &ElasticSearchIndexer{}
// ElasticSearchIndexer implements Indexer interface
type ElasticSearchIndexer struct {
client *elastic.Client
indexerName string
available bool
stopTimer chan struct{}
lock sync.RWMutex
}
type elasticLogger struct {
log.LevelLogger
}
func (l elasticLogger) Printf(format string, args ...interface{}) {
_ = l.Log(2, l.GetLevel(), format, args...)
}
// NewElasticSearchIndexer creates a new elasticsearch indexer
func NewElasticSearchIndexer(url, indexerName string) (*ElasticSearchIndexer, error) {
opts := []elastic.ClientOptionFunc{
elastic.SetURL(url),
elastic.SetSniff(false),
elastic.SetHealthcheckInterval(10 * time.Second),
elastic.SetGzip(false),
}
logger := elasticLogger{log.GetLogger(log.DEFAULT)}
if logger.GetLevel() == log.TRACE || logger.GetLevel() == log.DEBUG {
opts = append(opts, elastic.SetTraceLog(logger))
} else if logger.GetLevel() == log.ERROR || logger.GetLevel() == log.CRITICAL || logger.GetLevel() == log.FATAL {
opts = append(opts, elastic.SetErrorLog(logger))
} else if logger.GetLevel() == log.INFO || logger.GetLevel() == log.WARN {
opts = append(opts, elastic.SetInfoLog(logger))
}
client, err := elastic.NewClient(opts...)
if err != nil {
return nil, err
}
indexer := &ElasticSearchIndexer{
client: client,
indexerName: indexerName,
available: true,
stopTimer: make(chan struct{}),
}
ticker := time.NewTicker(10 * time.Second)
go func() {
for {
select {
case <-ticker.C:
indexer.checkAvailability()
case <-indexer.stopTimer:
ticker.Stop()
return
}
}
}()
return indexer, nil
}
const (
defaultMapping = `{
"mappings": {
"properties": {
"id": {
"type": "integer",
"index": true
},
"repo_id": {
"type": "integer",
"index": true
},
"title": {
"type": "text",
"index": true
},
"content": {
"type": "text",
"index": true
},
"comments": {
"type" : "text",
"index": true
}
}
}
}`
)
// Init will initialize the indexer
func (b *ElasticSearchIndexer) Init() (bool, error) {
ctx := graceful.GetManager().HammerContext()
exists, err := b.client.IndexExists(b.indexerName).Do(ctx)
if err != nil {
return false, b.checkError(err)
}
if !exists {
mapping := defaultMapping
createIndex, err := b.client.CreateIndex(b.indexerName).BodyString(mapping).Do(ctx)
if err != nil {
return false, b.checkError(err)
}
if !createIndex.Acknowledged {
return false, errors.New("init failed")
}
return false, nil
}
return true, nil
}
// Ping checks if elastic is available
func (b *ElasticSearchIndexer) Ping() bool {
b.lock.RLock()
defer b.lock.RUnlock()
return b.available
}
// Index will save the index data
func (b *ElasticSearchIndexer) Index(issues []*IndexerData) error {
if len(issues) == 0 {
return nil
} else if len(issues) == 1 {
issue := issues[0]
_, err := b.client.Index().
Index(b.indexerName).
Id(fmt.Sprintf("%d", issue.ID)).
BodyJson(map[string]interface{}{
"id": issue.ID,
"repo_id": issue.RepoID,
"title": issue.Title,
"content": issue.Content,
"comments": issue.Comments,
}).
Do(graceful.GetManager().HammerContext())
return b.checkError(err)
}
reqs := make([]elastic.BulkableRequest, 0)
for _, issue := range issues {
reqs = append(reqs,
elastic.NewBulkIndexRequest().
Index(b.indexerName).
Id(fmt.Sprintf("%d", issue.ID)).
Doc(map[string]interface{}{
"id": issue.ID,
"repo_id": issue.RepoID,
"title": issue.Title,
"content": issue.Content,
"comments": issue.Comments,
}),
)
}
_, err := b.client.Bulk().
Index(b.indexerName).
Add(reqs...).
Do(graceful.GetManager().HammerContext())
return b.checkError(err)
}
// Delete deletes indexes by ids
func (b *ElasticSearchIndexer) Delete(ids ...int64) error {
if len(ids) == 0 {
return nil
} else if len(ids) == 1 {
_, err := b.client.Delete().
Index(b.indexerName).
Id(fmt.Sprintf("%d", ids[0])).
Do(graceful.GetManager().HammerContext())
return b.checkError(err)
}
reqs := make([]elastic.BulkableRequest, 0)
for _, id := range ids {
reqs = append(reqs,
elastic.NewBulkDeleteRequest().
Index(b.indexerName).
Id(fmt.Sprintf("%d", id)),
)
}
_, err := b.client.Bulk().
Index(b.indexerName).
Add(reqs...).
Do(graceful.GetManager().HammerContext())
return b.checkError(err)
}
// Search searches for issues by given conditions.
// Returns the matching issue IDs
func (b *ElasticSearchIndexer) Search(ctx context.Context, keyword string, repoIDs []int64, limit, start int) (*SearchResult, error) {
kwQuery := elastic.NewMultiMatchQuery(keyword, "title", "content", "comments")
query := elastic.NewBoolQuery()
query = query.Must(kwQuery)
if len(repoIDs) > 0 {
repoStrs := make([]interface{}, 0, len(repoIDs))
for _, repoID := range repoIDs {
repoStrs = append(repoStrs, repoID)
}
repoQuery := elastic.NewTermsQuery("repo_id", repoStrs...)
query = query.Must(repoQuery)
}
searchResult, err := b.client.Search().
Index(b.indexerName).
Query(query).
Sort("_score", false).
From(start).Size(limit).
Do(ctx)
if err != nil {
return nil, b.checkError(err)
}
hits := make([]Match, 0, limit)
for _, hit := range searchResult.Hits.Hits {
id, _ := strconv.ParseInt(hit.Id, 10, 64)
hits = append(hits, Match{
ID: id,
})
}
return &SearchResult{
Total: searchResult.TotalHits(),
Hits: hits,
}, nil
}
// Close implements indexer
func (b *ElasticSearchIndexer) Close() {
select {
case <-b.stopTimer:
default:
close(b.stopTimer)
}
}
func (b *ElasticSearchIndexer) checkError(err error) error {
var opErr *net.OpError
if !(elastic.IsConnErr(err) || (errors.As(err, &opErr) && (opErr.Op == "dial" || opErr.Op == "read"))) {
return err
}
b.setAvailability(false)
return err
}
func (b *ElasticSearchIndexer) checkAvailability() {
if b.Ping() {
return
}
// Request cluster state to check if elastic is available again
_, err := b.client.ClusterState().Do(graceful.GetManager().ShutdownContext())
if err != nil {
b.setAvailability(false)
return
}
b.setAvailability(true)
}
func (b *ElasticSearchIndexer) setAvailability(available bool) {
b.lock.Lock()
defer b.lock.Unlock()
if b.available == available {
return
}
b.available = available
}