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forgejo/modules/queue/base_test.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

140 lines
3.5 KiB
Go

// Copyright 2023 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package queue
import (
"context"
"fmt"
"testing"
"time"
"github.com/stretchr/testify/assert"
)
func testQueueBasic(t *testing.T, newFn func(cfg *BaseConfig) (baseQueue, error), cfg *BaseConfig, isUnique bool) {
t.Run(fmt.Sprintf("testQueueBasic-%s-unique:%v", cfg.ManagedName, isUnique), func(t *testing.T) {
q, err := newFn(cfg)
assert.NoError(t, err)
ctx := context.Background()
_ = q.RemoveAll(ctx)
cnt, err := q.Len(ctx)
assert.NoError(t, err)
assert.EqualValues(t, 0, cnt)
// push the first item
err = q.PushItem(ctx, []byte("foo"))
assert.NoError(t, err)
cnt, err = q.Len(ctx)
assert.NoError(t, err)
assert.EqualValues(t, 1, cnt)
// push a duplicate item
err = q.PushItem(ctx, []byte("foo"))
if !isUnique {
assert.NoError(t, err)
} else {
assert.ErrorIs(t, err, ErrAlreadyInQueue)
}
// check the duplicate item
cnt, err = q.Len(ctx)
assert.NoError(t, err)
has, err := q.HasItem(ctx, []byte("foo"))
assert.NoError(t, err)
if !isUnique {
assert.EqualValues(t, 2, cnt)
assert.EqualValues(t, false, has) // non-unique queues don't check for duplicates
} else {
assert.EqualValues(t, 1, cnt)
assert.EqualValues(t, true, has)
}
// push another item
err = q.PushItem(ctx, []byte("bar"))
assert.NoError(t, err)
// pop the first item (and the duplicate if non-unique)
it, err := q.PopItem(ctx)
assert.NoError(t, err)
assert.EqualValues(t, "foo", string(it))
if !isUnique {
it, err = q.PopItem(ctx)
assert.NoError(t, err)
assert.EqualValues(t, "foo", string(it))
}
// pop another item
it, err = q.PopItem(ctx)
assert.NoError(t, err)
assert.EqualValues(t, "bar", string(it))
// pop an empty queue (timeout, cancel)
ctxTimed, cancel := context.WithTimeout(ctx, 10*time.Millisecond)
it, err = q.PopItem(ctxTimed)
assert.ErrorIs(t, err, context.DeadlineExceeded)
assert.Nil(t, it)
cancel()
ctxTimed, cancel = context.WithTimeout(ctx, 10*time.Millisecond)
cancel()
it, err = q.PopItem(ctxTimed)
assert.ErrorIs(t, err, context.Canceled)
assert.Nil(t, it)
// test blocking push if queue is full
for i := 0; i < cfg.Length; i++ {
err = q.PushItem(ctx, []byte(fmt.Sprintf("item-%d", i)))
assert.NoError(t, err)
}
ctxTimed, cancel = context.WithTimeout(ctx, 10*time.Millisecond)
err = q.PushItem(ctxTimed, []byte("item-full"))
assert.ErrorIs(t, err, context.DeadlineExceeded)
cancel()
// test blocking push if queue is full (with custom pushBlockTime)
oldPushBlockTime := pushBlockTime
timeStart := time.Now()
pushBlockTime = 30 * time.Millisecond
err = q.PushItem(ctx, []byte("item-full"))
assert.ErrorIs(t, err, context.DeadlineExceeded)
assert.True(t, time.Since(timeStart) >= pushBlockTime*2/3)
pushBlockTime = oldPushBlockTime
// remove all
cnt, err = q.Len(ctx)
assert.NoError(t, err)
assert.EqualValues(t, cfg.Length, cnt)
_ = q.RemoveAll(ctx)
cnt, err = q.Len(ctx)
assert.NoError(t, err)
assert.EqualValues(t, 0, cnt)
})
}
func TestBaseDummy(t *testing.T) {
q, err := newBaseDummy(&BaseConfig{}, true)
assert.NoError(t, err)
ctx := context.Background()
assert.NoError(t, q.PushItem(ctx, []byte("foo")))
cnt, err := q.Len(ctx)
assert.NoError(t, err)
assert.EqualValues(t, 0, cnt)
has, err := q.HasItem(ctx, []byte("foo"))
assert.NoError(t, err)
assert.False(t, has)
it, err := q.PopItem(ctx)
assert.NoError(t, err)
assert.Nil(t, it)
assert.NoError(t, q.RemoveAll(ctx))
}