[3.0] Supervisor nice option

[halaei]

Closing #549
This PR increments process niceness on each supervisor via config:

            'supervisor-1' => [
                'connection' => 'redis',
                'queue' => ['default'],
                'balance' => 'simple',
                'processes' => 10,
                'tries' => 3,
                'nice' => 5,
            ],

The supervisor calls proc_nice(5) to set niceness:

I don't know if you can regard it as backward compatible because of the change in supervisor option constructor. Also not sure if it has to be sent to 3.0 or master.

[driesvints]

It's backwards compatible because adding constructor arguments with defaults won't break anything. This is fine 👍

[driesvints]

@halaei Also: always add the full description for this PR to your main comment and not just link to a issue/pull request.

[halaei]

@driesvints Updated comment

[halaei]

Reading code, I see a --paused option:

{--paused : Start the supervisor in a paused state}

Reading that, I wish there was an option to pause a supervisor "only for a few seconds" before starting to scale for the first time. maybe a --pause=10 option.

[taylorotwell]

The PHP documentation states that the proc_nice value can also be negative?

[halaei]

@taylorotwell It will only work if the process is running as a superuser, otherwise an exception will be raised with this message:

proc_nice(): Only a super user may attempt to increase the priority of a process  

[browner12]

Support for Windows does not exist until PHP 7.2. Do we need to do anything in code to account for that, or will that be a documentation solution?

[halaei]

@browner12 This is an optional feature. If it is not supported on an environment you can simply not use it.

[driesvints]

@browner12 Windows support is lacking in general: #170

[mfn]

No happy about the 0 default and not allowing negative values!

[mfn]

This is problematic:

• a niceness of 0 is a valid value
• the (linux) default for niceness is usually 10

IMHO the correct way is to use null here.

[mfn]

0 is not a good value, see my other comment

[mfn]

• 0 is a valid niceness level
• so are negative values

This check, see my other comment, should be !== null

It doesn't matter that e.g. negative values are only allowed for root user rights. Don't outsmart the dev who might have run as root for whatever reason, etc.

[halaei]

@mfn The argument of proc_nice is the amount of increment to the niceness:

proc_nice ( int $increment ) : bool
proc_nice() changes the priority of the current process by the amount specified in increment.

http://php.net/manual/en/function.proc-nice.php

[halaei]

@mfn zero increment means no increment, so no need for null. About letting user to use negative values, that is fine for me, although I don't feel I should use it or run my workers as sudo or use Windows at all ;)

[halaei]

Maybe I should change the comments in the code from 'The process niceness' to 'Increment to the process niceness'?

[mfn]

@halaei thanks for correcting me, you're right!

Still, I vote for allowing negative values. It's not your decision how others want to run the code.

[driesvints]

This has now been released in v3.1.0

[Einenlum]

This doesn't seem documented: https://laravel.com/docs/11.x/horizon
Could it be added to the documentation somewhere?