-
-
Notifications
You must be signed in to change notification settings - Fork 5.2k
Symfony Messenger component documentation #9437
New issue
Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.
By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.
Already on GitHub? Sign in to your account
Changes from 1 commit
585491d
b40bc71
b26de80
88ba8fe
5c828e4
31a56ee
2493c90
bcfae23
25c0b6e
a15752b
fb88abc
509e149
3fb973c
32403ea
c5306b8
File filter
Filter by extension
Conversations
Jump to
Diff view
Diff view
- Loading branch information
There are no files selected for viewing
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,235 @@ | ||
.. index:: | ||
single: Message | ||
single: Components; Message | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. Messenger? |
||
|
||
The Message Component | ||
===================== | ||
|
||
The Message component helps application to send and receive messages | ||
to/from other applications or via | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. This phrase looks unfinished. Also, it's not a very descriptive description. Should we mention at least "message bus" or some key concept so the readers know undoubtely what problem does this component solve? Thanks! |
||
|
||
Concepts | ||
-------- | ||
|
||
.. image:: /_images/components/message/overview.png | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more.
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. messenger |
||
|
||
1. **Sender** | ||
Responsible for serializing and sending the message to _something_. This something can be a message broker or a 3rd | ||
party API for example. | ||
|
||
2. **Receiver** | ||
Responsible for deserializing and forwarding the messages to handler(s). This can be a message queue puller or an API | ||
endpoint for example. | ||
|
||
3. **Handler** | ||
Given a received message, contains the user business logic related to the message. In practice, that is just a PHP | ||
callable. | ||
|
||
Bus | ||
--- | ||
|
||
The bus is used to dispatch messages. MessageBus' behaviour is in its ordered middleware stack. When using | ||
the message bus with Symfony's FrameworkBundle, the following middlewares are configured for you: | ||
|
||
1. `LoggingMiddleware` (log the processing of your messages) | ||
2. `SendMessageMiddleware` (enable asynchronous processing) | ||
3. `HandleMessageMiddleware` (call the registered handle) | ||
|
||
use App\Message\MyMessage; | ||
|
||
$result = $this->get('message_bus')->handle(new MyMessage(/* ... */)); | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. Maybe use DI to get the There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. Added an example of constructing it manually. |
||
|
||
Handlers | ||
-------- | ||
|
||
Once dispatched to the bus, messages will be handled by a "message handler". A message handler is a PHP callable | ||
(i.e. a function or an instance of a class) that will do the required processing for your message. It _might_ return a | ||
result. | ||
|
||
namespace App\MessageHandler; | ||
|
||
use App\Message\MyMessage; | ||
|
||
class MyMessageHandler | ||
{ | ||
public function __invoke(MyMessage $message) | ||
{ | ||
// Message processing... | ||
} | ||
} | ||
|
||
|
||
<service id="App\Handler\MyMessageHandler"> | ||
<tag name="message_handler" /> | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. should be |
||
</service> | ||
|
||
**Note:** If the message cannot be guessed from the handler's type-hint, use the `handles` attribute on the tag. | ||
|
||
### Asynchronous messages | ||
|
||
Using the Message Component is useful to decouple your application but it also very useful when you want to do some | ||
asychronous processing. This means that your application will produce a message to a queuing system and consume this | ||
message later in the background, using a _worker_. | ||
|
||
#### Adapters | ||
|
||
The communication with queuing system or 3rd parties is for delegated to libraries for now. You can use one of the | ||
following adapters: | ||
|
||
- [PHP Enqueue bridge](https://github.com/sroze/enqueue-bridge) to use one of their 10+ compatible queues such as | ||
RabbitMq, Amazon SQS or Google Pub/Sub. | ||
|
||
Routing | ||
------- | ||
|
||
When doing asynchronous processing, the key is to route the message to the right sender. As the routing is | ||
application-specific and not message-specific, the configuration can be made within the `framework.yaml` | ||
configuration file as well: | ||
|
||
framework: | ||
message: | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more.
|
||
routing: | ||
'My\Message\MessageAboutDoingOperationalWork': my_operations_queue_sender | ||
|
||
Such configuration would only route the `MessageAboutDoingOperationalWork` message to be asynchronous, the rest of the | ||
messages would still be directly handled. | ||
|
||
If you want to do route all the messages to a queue by default, you can use such configuration: | ||
|
||
framework: | ||
message: | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more.
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. messenger |
||
routing: | ||
'My\Message\MessageAboutDoingOperationalWork': my_operations_queue_sender | ||
'*': my_default_sender | ||
|
||
Note that you can also route a message to multiple senders at the same time: | ||
|
||
framework: | ||
message: | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more.
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. messenger |
||
routing: | ||
'My\Message\AnImportantMessage': [my_default_sender, my_audit_sender] | ||
|
||
Same bus received and sender | ||
~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | ||
|
||
To allow us to receive and send messages on the same bus and prevent a loop, the message bus is equipped with the | ||
`WrapIntoReceivedMessage` received. It will wrap the received messages into `ReceivedMessage` objects and the | ||
`SendMessageMiddleware` middleware will know it should not send these messages. | ||
|
||
Your own sender | ||
--------------- | ||
|
||
Using the `SenderInterface`, you can easily create your own message sender. Let's say you already have an | ||
`ImportantAction` message going through the message bus and handled by a handler. Now, you also want to send this | ||
message as an email. | ||
|
||
1. Create your sender | ||
|
||
namespace App\MessageSender; | ||
|
||
use Symfony\Component\Message\SenderInterface; | ||
use App\Message\ImportantAction; | ||
|
||
class ImportantActionToEmailSender implements SenderInterface | ||
{ | ||
private $toEmail; | ||
private $mailer; | ||
|
||
public function __construct(\Swift_Mailer $mailer, string $toEmail) | ||
{ | ||
$this->mailer = $mailer; | ||
$this->toEmail = $toEmail; | ||
} | ||
|
||
public function send($message) | ||
{ | ||
if (!$message instanceof ImportantAction) { | ||
throw new \InvalidArgumentException(sprintf('Producer only supports "%s" messages.', ImportantAction::class)); | ||
} | ||
|
||
$this->mailer->send( | ||
(new \Swift_Message('Important action made')) | ||
->setTo($this->toEmail) | ||
->setBody( | ||
'<h1>Important action</h1><p>Made by '.$message->getUsername().'</p>', | ||
'text/html' | ||
) | ||
); | ||
} | ||
} | ||
|
||
2. Register your sender service | ||
|
||
services: | ||
App\MessageSender\ImportantActionToEmailSender: | ||
arguments: | ||
- "@mailer" | ||
- "%to_email%" | ||
|
||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. please remove blank line here |
||
tags: | ||
- message.sender | ||
|
||
3. Route your important message to the sender | ||
|
||
framework: | ||
message: | ||
routing: | ||
'App\Message\ImportantAction': [App\MessageSender\ImportantActionToEmailSender, ~] | ||
|
||
**Note:** this example shows you how you can at the same time send your message and directly handle it using a `null` | ||
(`~`) sender. | ||
|
||
Your own receiver | ||
----------------- | ||
|
||
A consumer is responsible of receiving messages from a source and dispatching them to the application. | ||
|
||
Let's say you already proceed some "orders" on your application using a `NewOrder` message. Now you want to integrate with | ||
a 3rd party or a legacy application but you can't use an API and need to use a shared CSV file with new orders. | ||
|
||
You will read this CSV file and dispatch a `NewOrder` message. All you need to do is your custom CSV consumer and Symfony will do the rest. | ||
|
||
1. Create your receiver | ||
|
||
namespace App\MessageReceiver; | ||
|
||
use Symfony\Component\Message\ReceiverInterface; | ||
use Symfony\Component\Serializer\SerializerInterface; | ||
|
||
use App\Message\NewOrder; | ||
|
||
class NewOrdersFromCsvFile implements ReceiverInterface | ||
{ | ||
private $serializer; | ||
private $filePath; | ||
|
||
public function __construct(SerializerInteface $serializer, string $filePath) | ||
{ | ||
$this->serializer = $serializer; | ||
$this->filePath = $filePath; | ||
} | ||
|
||
public function receive() : \Generator | ||
{ | ||
$ordersFromCsv = $this->serializer->deserialize(file_get_contents($this->filePath), 'csv'); | ||
|
||
foreach ($ordersFromCsv as $orderFromCsv) { | ||
yield new NewOrder($orderFromCsv['id'], $orderFromCsv['account_id'], $orderFromCsv['amount']); | ||
} | ||
} | ||
} | ||
|
||
2. Register your receiver service | ||
|
||
services: | ||
App\MessageReceiver\NewOrdersFromCsvFile: | ||
arguments: | ||
- "@serializer" | ||
- "%new_orders_csv_file_path%" | ||
|
||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. please remove blank line here |
||
tags: | ||
- message.receiver | ||
|
||
3. Use your consumer | ||
|
||
$ bin/console message:consume App\MessageReceived\NewOrdersFromCsvFile | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. Typo here, should be |
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
Messenger?