gitea/models
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
..
actions Support upload outputs and use needs context on Actions (#24230) 2023-04-22 16:12:41 -04:00
activities Localize activity heatmap (except tooltip) (#24131) 2023-04-17 14:26:01 -04:00
admin Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
asymkey Merge setting.InitXXX into one function with options (#24389) 2023-05-04 11:55:35 +08:00
auth Fix 500 error if there is a name conflict when edit authentication source (#23832) 2023-03-31 22:32:18 +08:00
avatars Avoid warning for system setting when start up (#23054) 2023-02-24 18:23:13 +08:00
db Improve milestone filter on issues page (#22423) 2023-04-30 09:12:49 -04:00
dbfs Merge setting.InitXXX into one function with options (#24389) 2023-05-04 11:55:35 +08:00
fixtures Allow adding new files to an empty repo (#24164) 2023-04-19 21:40:42 +08:00
git Use more specific test methods (#24265) 2023-04-22 17:56:27 -04:00
issues Refresh the refernce of the closed PR when reopening (#24231) 2023-05-08 14:39:32 +08:00
migrations Rewrite queue (#24505) 2023-05-08 19:49:59 +08:00
organization Add owner team permission check test (#24096) 2023-04-19 19:19:13 -04:00
packages Add RPM registry (#23380) 2023-05-05 20:33:37 +00:00
perm Rename repo.GetOwner to repo.LoadOwner (#22967) 2023-02-18 20:11:03 +08:00
project Improve GetBoards and getDefaultBoard (#22981) 2023-04-09 22:07:23 +08:00
pull refactor some functions to support ctx as first parameter (#21878) 2022-12-03 10:48:26 +08:00
repo Split "modules/context.go" to separate files (#24569) 2023-05-08 17:36:54 +08:00
secret Secrets storage with SecretKey encrypted (#22142) 2022-12-20 17:07:13 +08:00
system Avoid warning for system setting when start up (#23054) 2023-02-24 18:23:13 +08:00
unit Require at least one unit to be enabled (#24189) 2023-05-06 17:39:06 +08:00
unittest Rewrite queue (#24505) 2023-05-08 19:49:59 +08:00
user Add Debian package registry (#24426) 2023-05-02 12:31:35 -04:00
webhook Fix incorrect webhook time and use relative-time to display it (#24477) 2023-05-03 19:53:43 -04:00
error.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
fixture_generation.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
fixture_test.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
main_test.go Merge setting.InitXXX into one function with options (#24389) 2023-05-04 11:55:35 +08:00
migrate_test.go Check primary keys for all tables and drop ForeignReference (#21721) 2022-12-23 19:35:43 +08:00
migrate.go Check primary keys for all tables and drop ForeignReference (#21721) 2022-12-23 19:35:43 +08:00
org_team_test.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
org_team.go Remove org users who belong to no teams (#24247) 2023-04-24 15:52:38 -04:00
org_test.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
org.go refactor some functions to support ctx as first parameter (#21878) 2022-12-03 10:48:26 +08:00
repo_collaboration_test.go Rename repo.GetOwner to repo.LoadOwner (#22967) 2023-02-18 20:11:03 +08:00
repo_collaboration.go refactor some functions to support ctx as first parameter (#21878) 2022-12-03 10:48:26 +08:00
repo_test.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
repo_transfer_test.go Rename almost all Ctx functions (#22071) 2022-12-10 10:46:31 +08:00
repo_transfer.go Fix unclear IsRepositoryExist logic (#24374) 2023-04-28 14:14:26 -04:00
repo.go Split "modules/context.go" to separate files (#24569) 2023-05-08 17:36:54 +08:00