ag/event

A package that strives to best possible support the TYPO3 Flow PHP Framework with Domain Events as described in »Implementing Domain-Driven Design« by Vaughn Vernon.

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Type:typo3-flow-package

1.0.0 2015-02-03 10:31 UTC

README

TYPO3 Flow package to support domain events as described in the Domain Events chapter from: https://vaughnvernon.co/?page_id=168

Why?

Because using domain events to communicate information between aggregates, modules and bounded contexts decreases coupling and helps avoiding anemic domain models.

How?

See Ag.Shop for an example on how to integrate.

Event processing

There is a CLI command which can be run via ./flow event:process {eventHandlerName}, where the {eventHandlerName} is defined in Settings.yaml for example that way:

Ag:
  Event:
    eventHandlers:
      async:
        'Acme\Foo\EventHandler\SomeThingTriggeredEventHandler': TRUE

Per convention, the class name's namespace separators are substituted by an undersocre, so the key name in this case would be Acme_Foo_EventHandler_SomeThingTriggeredEventHandler.

Deamonizing configuration

The mentioned CLI command must be kept alive manually because it intrinsically will time out after a specified time range in order to avoid for example the MySQL connection timing out.

In order to achieve that, we have three recommendations here.

Using supervisord

Have a pool with the following configuration:

[program:some_thing]
command=/var/www/production/flow event:process Acme_Foo_EventHandler_SomeThingTriggeredEventHandler
environment=FLOW_CONTEXT="Production"
redirect_stderr=true
stdout_logfile=/var/www/production/Data/Logs/Supervisord.log
stderr_logfile=/var/www/production/Data/Logs/Supervisord_error.log
user=theuser
autostart=true
autorestart=true
stopsignal=QUIT
Using daemon

Start the process with a command similar to this:

daemon --name="some_thing" --env="FLOW_CONTEXT=Production" --respawn --stdout="/var/www/production/Data/Logs/DaemonStdOut.log" --stderr="/var/www/production/Data/Logs/DaemonStdErr.log" /var/www/production/flow event:process Acme_Foo_EventHandler_SomeThingTriggeredEventHandler

Once started, you can stop this deamon with daemon --stop --name="some_thing".

Using upstart

Have an upstart config with especially respawn active.