[5.7] Transactional jobs

[ed-fruty]

Added Transactional jobs.

With this PR we can easy to define that our job must execute in database transaction and it will automatically rollback if something will wrong.

Simple example:

class CreatePayoutOrderJob implements ShouldQueue, Transactional
{
   // ...

   public function __construct(User $user, Wallet $wallet, Money $amount)
   {
        // ...
   }

   public function handle()
   {
       // 1. Create payout order
       $payout = new Payout;
       $payout->wallet = $this->wallet;
       $payout->amount = $this->amount;
       $payout->user_id = $this->user;
       $payout->saveOrFail();  

      // 2. Remove amount from user balance.
      $user->decreaseBalanceFor($this->amount)->saveOrFail();

      // etc.
   }
}

And our data will still consistent event payout creation/balance changes will fail.

Probably, makes sense to add option like -t|--transactional to job generation command ?

[mfn]

TBH this style is freaking me out: "use"ing a variable and overwriting it in the same scope so the final call to it is the same? => That's a bit too much magic for my taste

[mfn]

How can we, except with documentation, better indicate to developers that this dbConnection method is possible to use?

The interface doesn't indicate it.

Also I'd like to see the naming a bit improved. E.g. getConnectionForTransaction or something, otherwise it's ambiguous.

[ed-fruty]

https://github.com/laravel/framework/blob/5.7/src/Illuminate/Queue/Jobs/Job.php#L171
https://github.com/laravel/framework/blob/5.7/src/Illuminate/Bus/Dispatcher.php#L156
https://github.com/laravel/framework/blob/5.7/src/Illuminate/Queue/Queue.php#L151
https://github.com/laravel/framework/blob/5.7/src/Illuminate/Queue/Queue.php#L163
https://github.com/laravel/framework/blob/5.7/src/Illuminate/Broadcasting/BroadcastEvent.php#L43
https://github.com/laravel/framework/blob/5.7/src/Illuminate/Broadcasting/BroadcastEvent.php#L60
https://github.com/laravel/framework/blob/5.7/src/Illuminate/Broadcasting/BroadcastManager.php#L119
https://github.com/laravel/framework/blob/5.7/src/Illuminate/Foundation/Http/FormRequest.php#L150

What about interface for this and another ones?

[mfn]

Can we do better then working with a global variable here?

[ed-fruty]

Yep, job can use any payload, given from container mock to detect works.
But this is a simple test like Taylor have used here

It also can use real DB connection, real transactions. It's only base ones.

[taylorotwell]

Honestly much simpler to just use DB::transaction(function () {}); within your jobs handle method.

[mfn]

Hello everyone,

based on an existing package and with permission of its original author, I've drafted a possible solution to tackle the "transactional events" problem.

At the moment it's a draft PR in my Laravel forked repo to first gather feedback from the community before approaching to create an official PR, to give things time to unfold / develop.

I invite everyone to participate in mfn#1 and share your feedback.

Thank you!

[driesvints]

@mfn think it's best that you actually send this in so people can give feedback. I doubt anyone will see it otherwise.