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forgejo/services/task/task.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

131 lines
3.4 KiB
Go

// Copyright 2019 Gitea. All rights reserved.
// SPDX-License-Identifier: MIT
package task
import (
"fmt"
admin_model "code.gitea.io/gitea/models/admin"
repo_model "code.gitea.io/gitea/models/repo"
user_model "code.gitea.io/gitea/models/user"
"code.gitea.io/gitea/modules/graceful"
"code.gitea.io/gitea/modules/json"
"code.gitea.io/gitea/modules/log"
base "code.gitea.io/gitea/modules/migration"
"code.gitea.io/gitea/modules/queue"
repo_module "code.gitea.io/gitea/modules/repository"
"code.gitea.io/gitea/modules/secret"
"code.gitea.io/gitea/modules/setting"
"code.gitea.io/gitea/modules/structs"
"code.gitea.io/gitea/modules/timeutil"
"code.gitea.io/gitea/modules/util"
)
// taskQueue is a global queue of tasks
var taskQueue *queue.WorkerPoolQueue[*admin_model.Task]
// Run a task
func Run(t *admin_model.Task) error {
switch t.Type {
case structs.TaskTypeMigrateRepo:
return runMigrateTask(t)
default:
return fmt.Errorf("Unknown task type: %d", t.Type)
}
}
// Init will start the service to get all unfinished tasks and run them
func Init() error {
taskQueue = queue.CreateSimpleQueue("task", handler)
if taskQueue == nil {
return fmt.Errorf("Unable to create Task Queue")
}
go graceful.GetManager().RunWithShutdownFns(taskQueue.Run)
return nil
}
func handler(items ...*admin_model.Task) []*admin_model.Task {
for _, task := range items {
if err := Run(task); err != nil {
log.Error("Run task failed: %v", err)
}
}
return nil
}
// MigrateRepository add migration repository to task
func MigrateRepository(doer, u *user_model.User, opts base.MigrateOptions) error {
task, err := CreateMigrateTask(doer, u, opts)
if err != nil {
return err
}
return taskQueue.Push(task)
}
// CreateMigrateTask creates a migrate task
func CreateMigrateTask(doer, u *user_model.User, opts base.MigrateOptions) (*admin_model.Task, error) {
// encrypt credentials for persistence
var err error
opts.CloneAddrEncrypted, err = secret.EncryptSecret(setting.SecretKey, opts.CloneAddr)
if err != nil {
return nil, err
}
opts.CloneAddr = util.SanitizeCredentialURLs(opts.CloneAddr)
opts.AuthPasswordEncrypted, err = secret.EncryptSecret(setting.SecretKey, opts.AuthPassword)
if err != nil {
return nil, err
}
opts.AuthPassword = ""
opts.AuthTokenEncrypted, err = secret.EncryptSecret(setting.SecretKey, opts.AuthToken)
if err != nil {
return nil, err
}
opts.AuthToken = ""
bs, err := json.Marshal(&opts)
if err != nil {
return nil, err
}
task := &admin_model.Task{
DoerID: doer.ID,
OwnerID: u.ID,
Type: structs.TaskTypeMigrateRepo,
Status: structs.TaskStatusQueue,
PayloadContent: string(bs),
}
if err := admin_model.CreateTask(task); err != nil {
return nil, err
}
repo, err := repo_module.CreateRepository(doer, u, repo_module.CreateRepoOptions{
Name: opts.RepoName,
Description: opts.Description,
OriginalURL: opts.OriginalURL,
GitServiceType: opts.GitServiceType,
IsPrivate: opts.Private,
IsMirror: opts.Mirror,
Status: repo_model.RepositoryBeingMigrated,
})
if err != nil {
task.EndTime = timeutil.TimeStampNow()
task.Status = structs.TaskStatusFailed
err2 := task.UpdateCols("end_time", "status")
if err2 != nil {
log.Error("UpdateCols Failed: %v", err2.Error())
}
return nil, err
}
task.RepoID = repo.ID
if err = task.UpdateCols("repo_id"); err != nil {
return nil, err
}
return task, nil
}