This document summarizes the process of transitioning a monolithic Symfony application to a service-oriented architecture (SOA). Key points include: - Splitting the application into bundles that can each be deployed on their own machines for scalability. - Using compiler passes to dynamically load bundles and their models, routes, and services. - Generating code from database schemas and API documentation from annotations to reduce boilerplate code. - Implementing a call router to allow services to communicate internally or externally across machines.

1. A SOA Approximation using Symfony
Joseluis Laso & Carlos Agudo

2. Who we are
•Carlos Agudo (@karloslupus)
•Joseluis Laso (@jl_laso)
And Others.. (Spanish team)
• Petar Georgiev (@pgkirilov)
• Daniel Abad (@ruudy_es)
• Noel García (@wolfwolker)
• Joaquín Fernández Campo
(@xocas__)
• Miguel Vilata
(@miguelvilata)

3. Where?

4. What is Digilant
DSP: Demand Side Platform => programmatic
advertising.
We have a backend to configure ours RTB bidder(s)
architecture.
• A programmatic campaign can have thousands of
parameters.

5. Long journey
From monolithic sf1 (legacy , 8 years of development)
to a SOA in sf2-3:

6. Requirements
• API Rest
• Auto Scalable (can be a huge huge demanding
platform)
• Symfony 2
• Easy to deploy

7. So?

8. Do not try this at home

9. Yes Symfony 2-3
Bundle: “A bundle is simply a structured set of files within a
directory that implement a single feature. “
-- We can split services as bundles, and start here.
This sounds weird??
Uncle Bob: “Don't leap into microservices just because it
sounds cool. Segregate the system into jars using a plugin
architecture first. If that's not sufficient, then consider
introducing service boundaries at strategic points.”

10. Some Questions arose
• One repo? One per service orchestrated with composer?
• One repo, let’s split it later, and coordinate with composer
later. (easier to develop)
• One Db per service? One db for the whole project, with
soft-relations between services?
• One Db for the whole project, let’s split it later. (easier to
develop??, careful with soft-relations, lost of referential
integrity)

11. Our motto
Let’s split it later
And let’s start!!

12. Backend Services View
Bundles

13. Yes, services bundles

14. Service- Machine
We can create as many services-machine as we want.
Depending on demand. We can cook them!!
Fully elastic scalability.
LineItem Service - Machine
LineItem Core
LineItem- Campaign - Machine
LineItem
Campaign
Core

15. Cooking Process 1
Using ansistrano (ansible), in each deploy, we can
select how many bundles a machine have.
Machine A- Geo and Creatives Machine B- All services but Pixel

16. Cooking Process 2
We need to dynamically load, our “bundles-service” on
deploy, our models, our routings, etc..
A lot of magic happens here!
Compiler pass to the rescue!

17. Cooking Process 3
In our AppKernel.php. We have the LocateBundles (utility
class) in a CoreBundle

18. Core Bundle
We have a CoreBundle, that act as a glue, (Compiler
passes)
• Communication between services (Can be http-
external, http-internal, process) We have a call
Router. API-REST, that’s why http-internal or external
• Some bussines event listeners (a filter for accounts,
softdelete, audit db listener)
• User-Permission Model

19. Models 1
In order to don’t get coupled to the persistence
implementation (Doctrine), don’t use annotations for
defining the model, map in an xml:

20. Models 2
We want to use our own folders:
Base?? We will explain it later, we have an
autogenerator of code.

21. Models 3
Compiler Pass to Load Models in our own folders.
We pass through our bundles, and
load models, in our folders.
The key:
DoctrineOrmMappingPass
We also use an alias:
LineItem:ThirdPartyData
Geo:City
ServiceName:Model

22. Others Compilers Passes
Here we load our services
(symfony) in each Bundle.
Also Lists calls (api-rest list
call, defaults limit per
model, orderby etc..)

23. Others Compilers Passes II
Load the routes per each bundle!

24. Controller Services
GeoBundle/Resources/config/services.yml
imports:
- resource: ServicesControllers/alpha.yml
We load versionable controllers (alpha, v1..) as services:
Right now: alpha (Remember WIP?)
Routes:
/alpha/creative/*
/current/creative/*

25. A lot of CRUD tables-controllers
We have a lot of master-
admin tables.
We have a RestController
for this purpose.
Controversy:
- We have a lot of
classes child of this
one.
- Needs refactor in
services!

26. 2nd part
And now ….
The funny part :)

27. Generator of code
Once upon a time …
We had time and we were youngs :) and we decide to
invest time creating a code generator to make our life
easier … you know ? developers ... this lazy race
With a lot of database schemas per create we thought
that was a good idea to convert this MWB files
directly in code … and was a really nightmare ...

28. Code generator (AKA mwb-import)
But … it worked
MWB file
it’s a ZIP
xml
sqlite
etc ..
unzip
generate
code with twig
generate
fixtures

29. Code generator (AKA mwb-import)

30. ApiDoc documentation generator
document !
document !
document !
document !
document !
document !

31. ApiDoc documentation generator
But not only generates documentation.
Why don’t use annotations to generate automatic
documentation of API routes ?
There are a couple of bundles in the market that do
this.
Again … we thought that we can do better.

32. ApiDoc documentation generator
/**
* @ApiDocDescription("Create an Account")
* @ApiDocMethod("post")
* @ApiDocRoute("/account")
* @ApiDocVersion("~")
* @ApiDocSubdomain("account")
* @ApiDocParam(name="maxBudgetValue",type="decimal",nullable=false,description="Account
maxBudgetValue")
* @ApiDocHeader(name="Authorization", placeholder="Authorization: Bearer {token}", type="string",
nullable=false, description="mandatory token obtained in login check call")
* @ApiDocReturnHeader("
* HTTP 200 OK
* Cache-Control: no-cache
* Content-Type: application/json
* ")
* @ApiDocReturnData(type="json", sample="{'id':'integer'}")
*/
public function createAction(Request $request)

33. Documentator
Features:
automatic creation of documentation in html format,
including a sandbox to test API endpoints

34. Documentator

35. Documentator
Features:
automatic creation of documentation in html format,
including a sandbox to test API endpoints
- export to
POSTMAN
collection

36. Call Router
How to make a call to a service that you even know
where is ?
LineItem Service - Machine
LineItem Core
LineItem- Campaign - Machine
LineItem
Campaign
Core

37. Call Router
How to call a controller method if you don’t know
where exactly is ?
Remember, we can deploy to n-servers …
To solve that we created a CallRouter that makes the
call internally (if the server has the service required)
or makes the call external (guzzle) if the service is in
another server.

38. Call Router
try {
// ...
$route = $this->router->match($pathInfo);
return $this->makeInternalCall($route['_controller'], $request);
} catch (ResourceNotFoundException $e) {
return $this->makeExternalCall($request->getMethod(), $subdomain,
$pathInfo, $request->getContent());
}