6f9c278559
# ⚠️ 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: 
94 lines
2.1 KiB
Go
94 lines
2.1 KiB
Go
// Copyright 2023 The Gitea Authors. All rights reserved.
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// SPDX-License-Identifier: MIT
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package queue
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import (
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"context"
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"sync"
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"unsafe"
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"code.gitea.io/gitea/modules/nosql"
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"gitea.com/lunny/levelqueue"
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"github.com/syndtr/goleveldb/leveldb"
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)
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type baseLevelQueueUnique struct {
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internal *levelqueue.UniqueQueue
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conn string
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cfg *BaseConfig
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mu sync.Mutex // the levelqueue.UniqueQueue is not thread-safe, there is no mutex protecting the underlying queue&set together
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}
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var _ baseQueue = (*baseLevelQueueUnique)(nil)
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func newBaseLevelQueueUnique(cfg *BaseConfig) (baseQueue, error) {
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conn, db, err := prepareLevelDB(cfg)
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if err != nil {
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return nil, err
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}
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q := &baseLevelQueueUnique{conn: conn, cfg: cfg}
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q.internal, err = levelqueue.NewUniqueQueue(db, []byte(cfg.QueueFullName), []byte(cfg.SetFullName), false)
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if err != nil {
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return nil, err
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}
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return q, nil
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}
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func (q *baseLevelQueueUnique) PushItem(ctx context.Context, data []byte) error {
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return baseLevelQueueCommon(q.cfg, q.internal, &q.mu).PushItem(ctx, data)
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}
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func (q *baseLevelQueueUnique) PopItem(ctx context.Context) ([]byte, error) {
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return baseLevelQueueCommon(q.cfg, q.internal, &q.mu).PopItem(ctx)
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}
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func (q *baseLevelQueueUnique) HasItem(ctx context.Context, data []byte) (bool, error) {
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q.mu.Lock()
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defer q.mu.Unlock()
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return q.internal.Has(data)
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}
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func (q *baseLevelQueueUnique) Len(ctx context.Context) (int, error) {
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q.mu.Lock()
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defer q.mu.Unlock()
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return int(q.internal.Len()), nil
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}
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func (q *baseLevelQueueUnique) Close() error {
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q.mu.Lock()
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defer q.mu.Unlock()
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err := q.internal.Close()
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_ = nosql.GetManager().CloseLevelDB(q.conn)
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return err
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}
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func (q *baseLevelQueueUnique) RemoveAll(ctx context.Context) error {
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q.mu.Lock()
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defer q.mu.Unlock()
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type levelUniqueQueue struct {
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q *levelqueue.Queue
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set *levelqueue.Set
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db *leveldb.DB
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}
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lq := (*levelUniqueQueue)(unsafe.Pointer(q.internal))
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members, err := lq.set.Members()
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if err != nil {
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return err // seriously corrupted
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}
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for _, v := range members {
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_, _ = lq.set.Remove(v)
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}
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for lq.q.Len() > 0 {
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if _, err = lq.q.LPop(); err != nil {
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return err
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}
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}
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return nil
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}
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