[0.6.x] Make it abundantly clear Bunny must run in a fiber

[WyriHaximus]

• Add fiber examples for all examples in the readme
• Convert the benchmark to be encapsulated in fibers
• Convert the tutorials to be encapsulated in fibers

@pulmer-cp @mdissington @andrew-demb @menturion @kostirez1 Since you either created or responded/emoted to some message in #192 or #191 I would love your feedback on this PR, addressing that in the documentation and examples. The changes in the readme start here: https://github.com/jakubkulhan/bunny/tree/0.6.x-make-it-abundantly-clear-Bunny-must-run-in-a-fiber?tab=readme-ov-file#always-run-moving-parts-in-a-fiber

[kostirez1]

Thank you so much for extending the documentation!

What I was looking for was a way to upgrade contributte/rabbitmq, that relies on the $client->run() synchronous helper method present in 0.5.x. If I understand it correctly, helper methods are the goal of #178, making the upgrade path much more straightforward. ❤️

[mdissington]

I think I saw "Cannot switch fibers in current execution context" when I was trying to shut my service down in a signal handler, I take it in that situation it is running outside of a fiber context?

I think I fixed it by calling my shutdown code in a Loop::futureTick(). I wasn't sure if I was doing things the "correct" way but it looks like I may have guessed correctly? :-)

[menturion]

I think I saw "Cannot switch fibers in current execution context" when I was trying to shut my service down in a signal handler, I take it in that situation it is running outside of a fiber context?

I think I fixed it by calling my shutdown code in a Loop::futureTick(). I wasn't sure if I was doing things the "correct" way but it looks like I may have guessed correctly? :-)

That's also exactly my case, terminating a worker via signal handler:

        $signals = [SIGINT, SIGTERM, SIGHUP];

        foreach ($signals as $signal) {
            Loop::addSignal($signal, static function () use ($consumerTag): void {
               self::_disconnect($consumerTag);
            });
        }

Within the _disconnect() method, I call the cancel(...) method for the channel object and disconnect() for the client object.

[andrew-demb]

This is great, thank you. I left some suggestions to improve it a bit from my PoV

[andrew-demb]

What does it mean "No perse needed"? I'm not sure about the translation.

[mdissington]

I spotted this, I think he may have meant "Not needed per se, as the Client..."?

[andrew-demb]

I suggest rephrasing it then to make it clear 👍

[WyriHaximus]

So, the client will open a connection when you try to open a channel if it's not connected or in the process of connecting:

bunny/src/Client.php

Lines 155 to 170 in 5a37f76

	/**
	* Creates and opens new channel.
	*
	* Channel gets first available channel id.
	*/
	public function channel(): ChannelInterface
	{
	if (!$this->isConnected()) {
	$this->connect();
	}
	if ($this->state === ClientState::Connecting) {
	$this->awaitConnection();
	}
	$channelId = $this->findChannelId();

Technically, that means there is no need to call Client::connect() directly, making Bunny on the connecting side lazy.

Similarly, when calling Client::disconnect(), it will close all open channels

bunny/src/Client.php

Lines 290 to 297 in 5a37f76

	$promises = [];
	foreach ($this->channels->all() as $channelId => $channel) {
	$promises[] = async(static function () use ($channel, $replyCode, $replyText): void {
	$channel->close($replyCode, $replyText);
	})();
	}
	await(all($promises));

. Thus, you don't have to call Channel::close() when disconnecting.

Updated the message a bit, but I can also remove them.

[andrew-demb]

Why is it necessary to use Loop::futureTick, but not async? I'm not sure whether it is a necessary detail to be known by the developer for classic use cases (php-fpm with no full async application)

[WyriHaximus]

Why is it necessary to use Loop::futureTick, but not async?

Loop::futureTick isn't strictly necessary, async is tho. You could do async(static fn etc etc)() to start the fiber right away, but using a Loop::futureTick schedules it right after the event loop has finished all it's incoming working from the kernel.

I'm not sure whether it is a necessary detail to be known by the developer for classic use cases (php-fpm with no full async application)

It shouldn't matter to them. Will have a look at adding a section for that tomorrow.

[WyriHaximus]

Thank you so much for extending the documentation!

What I was looking for was a way to upgrade contributte/rabbitmq, that relies on the $client->run() synchronous helper method present in 0.5.x. If I understand it correctly, helper methods are the goal of #178, making the upgrade path much more straightforward. ❤️

Correct, and @andrew-demb also made some good points on this topic.

Haven't been able to respond to everything, but pushed some changes based on suggestions.

[WyriHaximus]

I think I saw "Cannot switch fibers in current execution context" when I was trying to shut my service down in a signal handler, I take it in that situation it is running outside of a fiber context?

I think I fixed it by calling my shutdown code in a Loop::futureTick(). I wasn't sure if I was doing things the "correct" way but it looks like I may have guessed correctly? :-)

I think I saw "Cannot switch fibers in current execution context" when I was trying to shut my service down in a signal handler, I take it in that situation it is running outside of a fiber context?
I think I fixed it by calling my shutdown code in a Loop::futureTick(). I wasn't sure if I was doing things the "correct" way but it looks like I may have guessed correctly? :-)

That's also exactly my case, terminating a worker via signal handler:

        $signals = [SIGINT, SIGTERM, SIGHUP];

        foreach ($signals as $signal) {
            Loop::addSignal($signal, static function () use ($consumerTag): void {
               self::_disconnect($consumerTag);
            });
        }

Within the _disconnect() method, I call the cancel(...) method for the channel object and disconnect() for the client object.

Just pushed updated quickstart examples that cover this, also added the logic to both consumer examples in the readme.