forgejo-federation/routers/web
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
..
admin Rewrite queue (#24505) 2023-05-08 19:49:59 +08:00
auth Split "modules/context.go" to separate files (#24569) 2023-05-08 17:36:54 +08:00
devtest Remove untranslatable on_date key (#24106) 2023-04-15 13:01:54 +02:00
events Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
explore Sort users and orgs on explore by recency by default (#24279) 2023-05-06 22:04:55 +08:00
feed Pass 'not' to commit count (#24473) 2023-05-08 07:10:53 +00:00
healthcheck Refactor setting.Database.UseXXX to methods (#23354) 2023-03-07 18:51:06 +08:00
misc Refactor "route" related code, fix Safari cookie bug (#24330) 2023-04-27 02:06:45 -04:00
org Revert "Prevent a user with a different email from accepting the team invite" (#24531) 2023-05-05 15:59:12 +08:00
repo Split "modules/context.go" to separate files (#24569) 2023-05-08 17:36:54 +08:00
shared Move secrets and runners settings to actions settings (#24200) 2023-04-27 20:08:47 -04:00
user Split "modules/context.go" to separate files (#24569) 2023-05-08 17:36:54 +08:00
auth.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
auth_windows.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
base.go Improve template system and panic recovery (#24461) 2023-05-04 14:36:34 +08:00
goget.go refactor some functions to support ctx as first parameter (#21878) 2022-12-03 10:48:26 +08:00
home.go Refactor cookie (#24107) 2023-04-13 15:45:33 -04:00
metrics.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
nodeinfo.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
swagger_json.go Group template helper functions, remove Printf, improve template error messages (#23982) 2023-04-08 21:15:22 +08:00
web.go Rewrite queue (#24505) 2023-05-08 19:49:59 +08:00
webfinger.go Use User.ID instead of User.Name in ActivityPub API for Person IRI (#23823) 2023-04-04 10:08:23 +08:00