forgejo/cmd
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.go Merge setting.InitXXX into one function with options (#24389) 2023-05-04 11:55:35 +08:00
admin.go Handle OpenID discovery URL errors a little nicer when creating/editing sources (#23397) 2023-03-10 01:14:43 -05:00
admin_auth_ldap.go
admin_auth_ldap_test.go
admin_user.go Add command to bulk set must-change-password (#22823) 2023-02-14 16:12:19 -06:00
admin_user_change_password.go Provide the ability to set password hash algorithm parameters (#22942) 2023-02-19 15:35:20 +08:00
admin_user_create.go Provide the ability to set password hash algorithm parameters (#22942) 2023-02-19 15:35:20 +08:00
admin_user_delete.go Add context cache as a request level cache (#22294) 2023-02-15 21:37:34 +08:00
admin_user_generate_access_token.go Add command to bulk set must-change-password (#22823) 2023-02-14 16:12:19 -06:00
admin_user_list.go Add command to bulk set must-change-password (#22823) 2023-02-14 16:12:19 -06:00
admin_user_must_change_password.go Add command to bulk set must-change-password (#22823) 2023-02-14 16:12:19 -06:00
cert.go
cmd.go Merge setting.InitXXX into one function with options (#24389) 2023-05-04 11:55:35 +08:00
convert.go Support converting varchar to nvarchar for mssql database (#24105) 2023-04-17 21:22:10 +08:00
docs.go
doctor.go Merge setting.InitXXX into one function with options (#24389) 2023-05-04 11:55:35 +08:00
dump.go Merge setting.InitXXX into one function with options (#24389) 2023-05-04 11:55:35 +08:00
dump_repo.go Refactor the setting to make unit test easier (#22405) 2023-02-20 00:12:01 +08:00
embedded.go Merge setting.InitXXX into one function with options (#24389) 2023-05-04 11:55:35 +08:00
generate.go
hook.go Rewrite queue (#24505) 2023-05-08 19:49:59 +08:00
hook_test.go Refactor internal API for git commands, use meaningful messages instead of "Internal Server Error" (#23687) 2023-03-29 14:32:26 +08:00
keys.go Refactor internal API for git commands, use meaningful messages instead of "Internal Server Error" (#23687) 2023-03-29 14:32:26 +08:00
mailer.go Merge setting.InitXXX into one function with options (#24389) 2023-05-04 11:55:35 +08:00
main_test.go Merge setting.InitXXX into one function with options (#24389) 2023-05-04 11:55:35 +08:00
manager.go Refactor internal API for git commands, use meaningful messages instead of "Internal Server Error" (#23687) 2023-03-29 14:32:26 +08:00
manager_logging.go Refactor internal API for git commands, use meaningful messages instead of "Internal Server Error" (#23687) 2023-03-29 14:32:26 +08:00
migrate.go Refactor the setting to make unit test easier (#22405) 2023-02-20 00:12:01 +08:00
migrate_storage.go Make minio package support legacy MD5 checksum (#23768) 2023-03-28 11:10:24 -04:00
migrate_storage_test.go Add Debian package registry (#24426) 2023-05-02 12:31:35 -04:00
restore_repo.go Merge setting.InitXXX into one function with options (#24389) 2023-05-04 11:55:35 +08:00
serv.go Merge setting.InitXXX into one function with options (#24389) 2023-05-04 11:55:35 +08:00
web.go Merge setting.InitXXX into one function with options (#24389) 2023-05-04 11:55:35 +08:00
web_acme.go
web_graceful.go
web_https.go