So I found this [linter](https://github.com/Riverside-Healthcare/djlint)
which features a mode for go templates, so I gave it a try and it did
find a number of valid issue, like unbalanced tags etc. It also has a
number of bugs, I had to disable/workaround many issues.

Given that this linter is written in python, this does add a dependency
on `python` >= 3.8 and `poetry` to the development environment to be
able to run this linter locally.

- `e.g.` prefixes on placeholders are removed because the linter had a
false-positive on `placeholder="e.g. cn=Search"` for the `attr=value`
syntax and it's not ideal anyways to write `e.g.` into a placeholder
because a placeholder is meant to hold a sample value.
- In `templates/repo/settings/options.tmpl` I simplified the logic to
not conditionally create opening tags without closing tags because this
stuff confuses the linter (and possibly the reader as well).

Although some features are mixed together in this PR, this PR is not
that large, and these features are all related.

Actually there are more than 70 lines are for a toy "test queue", so
this PR is quite simple.

Major features:

1. Allow site admin to clear a queue (remove all items in a queue)
* Because there is no transaction, the "unique queue" could be corrupted
in rare cases, that's unfixable.
* eg: the item is in the "set" but not in the "list", so the item would
never be able to be pushed into the queue.
* Now site admin could simply clear the queue, then everything becomes
correct, the lost items could be re-pushed into queue by future
operations.
3. Split the "admin/monitor" to separate pages
4. Allow to download diagnosis report
* In history, there were many users reporting that Gitea queue gets
stuck, or Gitea's CPU is 100%
    * With diagnosis report, maintainers could know what happens clearly

The diagnosis report sample:
[gitea-diagnosis-20230510-192913.zip](https://github.com/go-gitea/gitea/files/11441346/gitea-diagnosis-20230510-192913.zip)
, use "go tool pprof profile.dat" to view the report.


Screenshots:


![image](https://github.com/go-gitea/gitea/assets/2114189/320659b4-2eda-4def-8dc0-5ea08d578063)


![image](https://github.com/go-gitea/gitea/assets/2114189/c5c46fae-9dc0-44ca-8cd3-57beedc5035e)


![image](https://github.com/go-gitea/gitea/assets/2114189/6168a811-42a1-4e64-a263-0617a6c8c4fe)

---------

Co-authored-by: Jason Song <i@wolfogre.com>
Co-authored-by: Giteabot <teabot@gitea.io>

# ⚠️ 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)

It seems that we really need the "context function" soon. So we should
clean up the helper functions first.

Major changes:

* Improve StringUtils and add JsonUtils
* Remove one-time-use helper functions like CompareLink
* Move other code (no change) to util_avatar/util_render/util_misc (no
need to propose changes for them)

I have tested the changed templates:


![image](https://user-images.githubusercontent.com/2114189/235283862-608dbf6b-2da3-4d06-8157-b523ca93edb4.png)


![image](https://user-images.githubusercontent.com/2114189/235283888-1dfc0471-e622-4d64-9d76-7859819580d3.png)


![image](https://user-images.githubusercontent.com/2114189/235283903-d559f14d-4abb-4a50-915f-2b9cbc381a7a.png)


![image](https://user-images.githubusercontent.com/2114189/235283955-b7b5adea-aca3-4758-b38a-3aae3f7c6048.png)

---------

Co-authored-by: Giteabot <teabot@gitea.io>

Before, 500 error


![image](https://user-images.githubusercontent.com/2114189/234170176-403ffd1b-ec27-42be-bff9-86184dc8d74d.png)

Follow #24097 and #24285

And add a devtest page for modal action button testing.
http://localhost:3000/devtest/fomantic-modal

Now the `modal_actions_confirm.tmpl` could support: green / blue /
yellow positive buttons, the negative button is "secondary".

ps: this PR is only a small improvement, there are still a lot of
buttons not having proper colors. In the future these buttons could be
improved by this approach.

These buttons could also be improved according to the conclusion of
#24285 in the future.



![image](https://user-images.githubusercontent.com/2114189/233847773-a6d6b29b-7b5c-490e-8425-40dfd0ad2529.png)


And add GitHub-like single danger button (context:
https://github.com/go-gitea/gitea/issues/24285#issuecomment-1519100312)


![image](https://user-images.githubusercontent.com/2114189/233891566-055d7611-894d-4d5a-baf5-f6369180bf8d.png)

---------

Co-authored-by: silverwind <me@silverwind.io>

This refactors the `shared/datetime/short|long|full` templates into a
template helper function, which allows us to render absolute date times
within translatable phrases.

- Follows #23988
- The first attempt was in #24055
- This should help #22664 

Changes:
1. Added the `DateTime` template helper that replaces the
`shared/datetime/short|long|full` templates
2. Used find-and-replace with varying regexes to replace the templates
from step 1 (for example, `\{\{template "shared/datetime/(\S+) \(dict
"Datetime" ([^"]+) "Fallback" ([^\)]+\)?) ?\)?\}\}` -> `{{DateTime "$1
$2 $3}}`)
3. Used the new `DateTime` helper in the issue due date timestamp
rendering

# Before

![image](https://user-images.githubusercontent.com/20454870/233791256-b454c455-aca0-4b76-b300-7866c7bd529e.png)

# After

![image](https://user-images.githubusercontent.com/20454870/233790809-c4913355-2822-4657-bb29-2298deb6d4b3.png)

---------

Signed-off-by: Yarden Shoham <git@yardenshoham.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

Co-Author: @wxiaoguang 

This is the first step of #24229. And this PR will only includes html
changes, and followed by other PRs that fine tune css and change to
submenus.

After:

Admin Level

<img width="1400" alt="Screen Shot 2023-04-21 at 10 07 16"
src="https://user-images.githubusercontent.com/17645053/233523870-f848b61d-056a-4b41-9760-a9a49fea1fe8.png">

User Level

<img width="1422" alt="Screen Shot 2023-04-21 at 10 07 23"
src="https://user-images.githubusercontent.com/17645053/233523878-979adb20-a657-43d9-99a6-ad414010c0ef.png">

Repo Level

<img width="1404" alt="Screen Shot 2023-04-21 at 10 07 07"
src="https://user-images.githubusercontent.com/17645053/233523863-337440bd-c03a-4dfd-87fa-cef40300bfe0.png">

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

Co-Author: @wxiaoguang 

This PR is to fix
https://github.com/go-gitea/gitea/issues/23318#issuecomment-1506275446 .
The way to fix this in this PR is to use `delete_modal_actions.tmpl`
here both to fix this issue and keep ui consistency (as suggested by
[TODO
here](4299c3b7db/templates/projects/view.tmpl (L161)))

And this PR also refactors `delete_modal_actions.tmpl` and its related
styles, and use the template for more modal actions:

1. Added template attributes:
* locale
* ModalButtonStyle: "yes" (default) or "confirm"
* ModalButtonCancelText
* ModalButtonOkText

2. Rename `delete_modal_actions.tmpl` template to
`modal_actions_confirm.tmpl` because it is not only used for action
modals deletion now.

3. Refactored css related to modals into `web_src/css/modules/modal.css`
and improved the styles.

4. Also use the template for PR deletion modal and remove issue
dependency modal.

5. Some modals should also use the template, but not sure how to open
them, so mark these modal actions by `{{/* TODO: Convert to
base/modal_actions_confirm */}}`

After (Also tested on arc green):

Hovering on the left buttons

<img width="711" alt="Screen Shot 2023-04-23 at 15 17 12"
src="https://user-images.githubusercontent.com/17645053/233825650-76307e65-9255-44bb-80e8-7062f58ead1b.png">

<img width="786" alt="Screen Shot 2023-04-23 at 15 17 21"
src="https://user-images.githubusercontent.com/17645053/233825652-4dc6f7d1-a180-49fb-a468-d60950eaee0d.png">

Test for functionalities:

https://user-images.githubusercontent.com/17645053/233826857-76376fda-022c-42d0-b0f3-339c17ca4e59.mov

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

- Added [GitHub's `relative-time` element](https://github.com/github/relative-time-element)
- Converted all formatted timestamps to use this element
- No more flashes of unstyled content around time elements
- These elements are localized using the `lang` property of the HTML file
- Relative (e.g. the activities in the dashboard) and duration (e.g.
server uptime in the admin page) time elements are auto-updated to keep
up with the current time without refreshing the page
- Code that is not needed anymore such as `formatting.js` and parts of `since.go` have been deleted

Replaces #21440
Follows #22861

## Screenshots

### Localized

![image](https://user-images.githubusercontent.com/20454870/230775041-f0af4fda-8f6b-46d3-b8e3-d340c791a50c.png)

![image](https://user-images.githubusercontent.com/20454870/230673393-931415a9-5729-4ac3-9a89-c0fb5fbeeeb7.png)

### Tooltips

#### Native for dates

![image](https://user-images.githubusercontent.com/20454870/230797525-1fa0a854-83e3-484c-9da5-9425ab6528a3.png)

#### Interactive for relative

![image](https://user-images.githubusercontent.com/115237/230796860-51e1d640-c820-4a34-ba2e-39087020626a.png)

### Auto-update

![rec](https://user-images.githubusercontent.com/20454870/230672159-37480d8f-435a-43e9-a2b0-44073351c805.gif)

---------

Signed-off-by: Yarden Shoham <git@yardenshoham.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: delvh <dev.lh@web.de>

* Add main aria landmark to templates
 * Adjust some titles to improve understanding of location in navigation

Contributed by @Forgejo

Fix #21207

Co-authored-by: Lauris BH <lauris@nix.lv>

* Refactor `i18n` to `locale`

- Currently we're using the `i18n` variable naming for the `locale`
struct. This contains locale's specific information and cannot be used
for general i18n purpose, therefore refactoring it to `locale` makes
more sense.
- Ref: https://github.com/go-gitea/gitea/pull/20096#discussion_r906699200

* Update routers/install/install.go

Add number in queue status to the monitor page so that administrators can
assess how much work is left to be done in the queues.

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

* Start adding mechanism to return unhandled data

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Create pushback interface

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Add Pausable interface to WorkerPool and Manager

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Implement Pausable and PushBack for the bytefifos

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Implement Pausable and Pushback for ChannelQueues and ChannelUniqueQueues

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Wire in UI for pausing

Signed-off-by: Andrew Thornton <art27@cantab.net>

* add testcases and fix a few issues

Signed-off-by: Andrew Thornton <art27@cantab.net>

* fix build

Signed-off-by: Andrew Thornton <art27@cantab.net>

* prevent "race" in the test

Signed-off-by: Andrew Thornton <art27@cantab.net>

* fix jsoniter mismerge

Signed-off-by: Andrew Thornton <art27@cantab.net>

* fix conflicts

Signed-off-by: Andrew Thornton <art27@cantab.net>

* fix format

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Add warnings for no worker configurations and prevent data-loss with redis/levelqueue

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Use StopTimer

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: Lauris BH <lauris@nix.lv>
Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

* Update JS dependencies

- Update all JS dependencies
- For octicons, rename trashcan to trash
- For svgo, migrate to v2 api, output seems to have slightly changed but icons look the same
- For stylelint, update config, fix custom property duplicates
- For monaco, drop legacy Edge support
- For eslint, enable new rules, fix new issues
- For less-loader, remove deprecated import syntax

* update svgo usage in generate-images and rebuild logo.svg with it

* Replace more icons with SVG

- Replace remaining icons on admin page with SVG
- Fix vertical menu background on arc-green
- Minor improvments to frontpage repo search
- More icon replacements here and there

* fix integration

* whitespace tweak

* add comment

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

* Add class to page content to unify top margin

Previously pages would individually set this margin but some didn't so
content would stick to the header without any space. Resolve this by
adding a new class that is added on all pages. The only place where we
remove this margin again is on the pages with menu or wrapper in the
header.

* fix admin notices

* fix team pages

* fix loading segment on gitgraph for arc-green

* fix last missing case

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

* Make WorkerPools and Queues flushable

Adds Flush methods to Queues and the WorkerPool
Further abstracts the WorkerPool
Adds a final step to Flush the queues in the defer from PrintCurrentTest
Fixes an issue with Settings inheritance in queues

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Change to for loop

* Add IsEmpty and begin just making the queues composed WorkerPools

* subsume workerpool into the queues and create a flushable interface

* Add manager command

* Move flushall to queue.Manager and add to testlogger

* As per @guillep2k

* as per @guillep2k

* Just make queues all implement flushable and clean up the wrapped queue flushes

* cope with no timeout

Co-authored-by: Lauris BH <lauris@nix.lv>

* Queue: Add generic graceful queues with settings

* Queue & Setting: Add worker pool implementation

* Queue: Add worker settings

* Queue: Make resizing worker pools

* Queue: Add name variable to queues

* Queue: Add monitoring

* Queue: Improve logging

* Issues: Gracefulise the issues indexer

Remove the old now unused specific queues

* Task: Move to generic queue and gracefulise

* Issues: Standardise the issues indexer queue settings

* Fix test

* Queue: Allow Redis to connect to unix

* Prevent deadlock during early shutdown of issue indexer

* Add MaxWorker settings to queues

* Merge branch 'master' into graceful-queues

* Update modules/indexer/issues/indexer.go

Co-Authored-By: guillep2k <18600385+guillep2k@users.noreply.github.com>

* Update modules/indexer/issues/indexer.go

Co-Authored-By: guillep2k <18600385+guillep2k@users.noreply.github.com>

* Update modules/queue/queue_channel.go

Co-Authored-By: guillep2k <18600385+guillep2k@users.noreply.github.com>

* Update modules/queue/queue_disk.go

* Update modules/queue/queue_disk_channel.go

Co-Authored-By: guillep2k <18600385+guillep2k@users.noreply.github.com>

* Rename queue.Description to queue.ManagedQueue as per @guillep2k

* Cancel pool workers when removed

* Remove dependency on queue from setting

* Update modules/queue/queue_redis.go

Co-Authored-By: guillep2k <18600385+guillep2k@users.noreply.github.com>

* As per @guillep2k add mutex locks on shutdown/terminate

* move unlocking out of setInternal

* Add warning if number of workers < 0

* Small changes as per @guillep2k

* No redis host specified not found

* Clean up documentation for queues

* Update docs/content/doc/advanced/config-cheat-sheet.en-us.md

* Update modules/indexer/issues/indexer_test.go

* Ensure that persistable channel queue is added to manager

* Rename QUEUE_NAME REDIS_QUEUE_NAME

* Revert "Rename QUEUE_NAME REDIS_QUEUE_NAME"

This reverts commit 1f83b4fc9b.

Co-authored-by: guillep2k <18600385+guillep2k@users.noreply.github.com>
Co-authored-by: Lauris BH <lauris@nix.lv>
Co-authored-by: techknowlogick <matti@mdranta.net>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>