Proposal: Add reload mechanism to html render

[welkeyever]

Describe the solution you'd like

Add or replace the way of rendering HTML in order to let the server reload HTML templates without restarting.

Describe alternatives you've considered

A timer or a file system watcher may help to decide whether to reload or not.

Additional context

Be aware of performance overhead. DO NOT reload it every time when render api is called.

[stephenzhang0713]

I would like to help with this issue

[stephenzhang0713]

Some of my thoughts on this issue

• By analyzing the source code of hertz, I found that the method of loading HTML is located in pkg/route/engine.go, and there are two main functions in engine.go which are responsible for executing loading HTML, namely LoadHTMLGlob and LoadHTMLFiles
• As mentioned in the description of the issue above, consider using a timer or watcher to listen to the file system, I think we can use a channel to listen for events and perform a reload once the files in the directory change (read or write)

[welkeyever]

Yes, LoadHTMLGlob and LoadHTMLFiles will set the HTMLRender immediately, so here a new auto-reloading Render may help do the reload job(check the files during .Instance()).

stage 1 of the impl: users can choose the auto-reloading Render for their project.
stage2 : switching automatically between normal Render and auto-reloading Render according to some conditions(maybe config/env/etc.)

[hiqsociety]

possible to get ideas from here? it's the fastest templating engine but doesnt do live reload
https://github.com/Joker/jade

[Duslia]

Hi~ I am wondering how it's going? Do you encounter any difficulties? You may join our Feishu Chat Group to discuss more details about this task.

[stephenzhang0713]

Hi~ I am wondering how it's going? Do you encounter any difficulties? You may join our Feishu Chat Group to discuss more details about this task.

Sorry I just saw your message, I have been in hospital for a month, I'm sorry to reply to you too late

[byene0923]

what during .Instance() mean ? auto-reloading Render may add some time conditions such as cron ? and set a default cron if is auto-reloading Render

[byene0923]

i see fiber support this ,every time do the Render() will the tpl be reloaded if engine.reload is ture
https://github.com/gofiber/fiber/blob/c450072f4a490355dffc31f5cc36036a2383b1c7/internal/template/html/html.go#L187

so may hertz do as fiber ?