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Jackson F. de A. Mafrahttp://about.me/jacksonfdam https://bitbucket.org/jacksonfdam https://github.com/jacksonfdam http://linkedin.com/in/jacksonfdam @jacksonfdam
Software Engineer at Aggrega Group, mobile training instructor at Targettrust. Developer for 15 years with background in e-commerce projects and real estate, since 2009 with focused interests for the development of mobile and MEAP and applications interfaces.
Cross-cutting concerns are conceptually separate from (but often embedded directly
within) the application’s business logic. Separating these cross-cutting concerns from the business logic is where aspect- oriented
programming (AOP) goes to work.
Whereas DI helps you decouple your application objects from each other, AOP helps you decouple cross-cutting concerns from the
objects that they affect.
Centralize concerns implementation More reusable code
Cleaner code Write less code
Easy to understand More maintainable
Less boilerplate code More interesting work
Why AOP?
Advice defines what needs to be applied and when. Jointpoint is where the advice is applied. Pointcut is the combination of different joinpoints where the advice needs to be applied. Aspect is applying the Advice at the pointcuts.
Definitions
Advice Types
Method
Method
Method
Method
Exception
Before advice
After advice
After returning advice
Around advice
Throws advice
AOP is a PECL extension that enables you to use Aspect Oriented Programming in PHP, without the need to compile or proceed to any other intermediate step before publishing your code.
The AOP extension is designed to be the easiest way you can think of for integrating AOP to PHP.
AOP aims to allow separation of cross-cutting concerns (cache, log, security, transactions, ...)
https://github.com/AOP-PHP/AOP
AOP
<?php class UsersServices { public function authorizeUser () { //some stuff only the admin should do echo "Calling authorizeUser"; }
public function authorizeGroup () { //some stuff only the admin should do echo "Calling authorizeGroup"; } }
Basic tutorial
<?php class UsersServices { public function authorizeUser () { //some stuff only the admin should do echo "Calling authorizeUser"; }
public function authorizeGroup () { //some stuff only the admin should do echo "Calling authorizeGroup"; } }
Basic tutorial
Now you want your code to be safe, you don't want non admin users to be able to call authorize methods.
Basic tutorial
Add some code to check the credentials "IN" you UsersServices class. The drawback is that it will pollute your code, and your core service will be less readable.
Let the clients have the responsibility to check the credentials when required. The drawbacks are that you will duplicate lots of code client side if you have to call the service from multiple places
Add some kind of credential proxy that will check the credentials before calling the actual service. The drawbacks are that you will have to write some extra code, adding another class on the top of your services.
What are your solutions ?
Moreover, those solutions tends to increase in complexity while you are adding more cross-cutting concerns like caching or logging.
What are your solutions ?
That's where AOP comes into action as you will be able to tell PHP to do some extra actions while calling your MyServices's admin methods.
What are your solutions ?
So let's first write the rule needed to check if we can or cannot access the admin services.
<?php function adviceForDoAdmin () { if ((! isset($_SESSION['user_type'])) || ($_SESSION['user_type'] !== 'admin')) { throw new Exception('Sorry, you should be an admin to do this'); } }
What are your solutions ?
Dead simple : we check the current PHP session to see if there is something telling us the current user is an admin (Of course we do realize that you may have more complex routines to do that, be we'll keep this for the example)
What are your solutions ?
Now, let's use AOP to tell PHP to execute this method "before" any execution of admin methods.
<?php aop_add_before('UsersServices->authorize*()', 'adviceForDoAdmin');
What are your solutions ?
Now, each time you'll invoke a method of an object of the class UsersServices, starting by authorize, AOP will launch the function basicAdminChecker before the called method.
What are your solutions ?
<?php //session is started and we added the above examples to configure UsersServices & basicAdminChecker
$services = new UsersServices(); try { $services-> authorizeUser();//will raise an exception as nothing in the current session tells us we are an admin } catch (Exception $e) { echo "You cannot access the service, you're not an admin"; }
$_SESSION['user_type'] = 'admin';//again, this is ugly for the sake of the example
try { $service-> authorizeUser(); $service-> authorizeGroup(); } catch (Exception $e) { //nothing will be caught here, we are an admin }
To know the best method of logging data of different contexts for specific environments
such as test/dev and production
Take Away
Even with use of computers there was a real need to measure the overall performance of any reasearch
Early 1980's there was a Instrument called VELA (virtual laboratory) used for data harvesting
History of Logging
Late 1980's, A device was invented to collect information through sensors
Later then data logging/harvesting has been used widely in all applications/reasearches/products.
History of Logging
Track Users activity/Movement
Transaction Logging
Track user errors
System level failures/warnings
Research Data collection and Interpretation
Need of Logging
Error / Exception logs
Access logs
System logs
Application logs
Database logs
Transaction logs
Mailer logs etc...
Types of Logging
Debug Information - Errors (connections, uncaught exceptions, resource exhaustion)
Narrative Information - Methods Calls, Event Triggers
Business Events - Purchases, Logins, Registrations, Unsubscribes
Application Log
ssh webserver@mydomain.net tail -f /var/log/nginx/my-site.access.log tail -f /var/log/my.application.log
ssh data@mydomain.net tail -f /var/log/mysql/mysql.log
ssh q@mydomain.net
tail -f /var/log/rabbitmq/nodename.log
Keeping Track Of All This
Apache/PHP <VirtualHost *:80>
<Directory /var/www/html/> Options Indexes FollowSymLinks MultiViews AllowOverride All Order allow,deny allow from all
</Directory> ErrorLog ${APACHE_LOG_DIR}/error.log LogLevel warn CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>
Current Conventions
Monolog is a PHP library that support different levels of logging for PHP Applications and depends on PSR.
Inspired by Python Logbook library
Provides stack of handlers
More Powerful than conventional way of logging in applications
Monolog Enters Here
Monolog sends your logs to files, sockets, inboxes, databases and various web services.
Channel based approach
Different stack of handlers for specific channels
Pile up handler stack based on severity.
Format Interpretation depending on severity and channel
Prevents Bubbling when severity is reached
What's different ?
Log Levels 2013 - PSR03 - PHP Logging Interface Standard
Phrase / Severity
emergency Emergency: system is unusable alert Alert: action must be taken immediately critical Critical: critical conditions error Error: error conditions warning Warning: warning conditions notice Notice: normal but significant condition info Informational: informational messages debug Debug: debug-level messages
http://www.php-fig.org/psr/psr-3/
Log Levels
error_log is too basic (message, file, line)
difficult to read / parse
depends on “error_reporting” setting
Why?
monolog
phpconsole
log4php
RavenPHP + Sentry
FirePHP (dev environment)
Roll your own Logging Options
Logging Options
Fire & forget
Minimum or zero latency
Highly available
Should be PSR-3 compatible
Log everything:
- Exceptions - Errors - Fatal Errors
Requirements (for everyone)
MonologMonologErrorHandler ->
handleException()
MonologLogger ->log()
MonologHandler ->handle()
MongoDB
Option to have different channel for different module
Custom detailing
Different handlers for different development
Thorough participation in different stages of lifecycle
Open for third party integration
Readable and Beautiful Layered message
Advantages
PSR-3 makes it easy
However you want…
Monolog has loads:
- syslog-compatible / error_log
- Email, HipChat
- AMQP, Sentry, Zend Monitor, Graylog2
- Redis, MongoDB, CouchDB
Sending Log Messages
CakePHP - https://github.com/jadb/cakephp-monolog Symfony2 - https://github.com/symfony/MonologBundle Slim – https://github.com/flynsarmy/Slim-Monolog Zend2 - https://packagist.org/packages/enlitepro/enlite-monolog CodeIgniter - https://github.com/pfote/Codeigniter-Monolog Laravel – Inbuilt Support. Drupal - https://drupal.org/project/monolog Wordpress - https://packagist.org/packages/fancyguy/wordpress-monolog
more: https://github.com/Seldaek/monolog#frameworks-integration
Do you use Frameworks / CMS ?
Monolog is available on Packagist, which means that you can install it via Composer.
composer require 'monolog/monolog:1.13.*'
Installation
<?php
use Monolog\Logger;
use Monolog\Handler\StreamHandler;
// create a log channel
$log = new Logger('name');
$log->pushHandler(new StreamHandler('path/to/your.log', Logger::WARNING));
// add records to the log
$log->addWarning('Foo');
$log->addError('Bar');
Basic Usage
<?php
use MonologLogger;
use MonologHandlerFingersCrossedHandler;
use MonologHandlerStreamHandler;
$logEnv = getenv('LOG_LEVEL');
$level = empty($logLevel) ? $logEnv : Logger::WARNING;
$appLog = new Logger('AppLog');
$strHandler = new StreamHandler('/var/log/app.log', Logger::DEBUG);
$fcHandler = new FingersCrossedHandler($strHandler, $level);
$appLog−>pushHandler($fcHandler);
$appLog−>debug('LOGGING!');
Loggers And Handlers
<?php
// Set A Log Level $logEnv = getenv(‘LOG_LEVEL');
$level = empty($logLevel) ? $logEnv : Logger::WARNING;
// Create A Logger $appLog = new Logger('AppLog');
Loggers And Handlers
<?php
// Create Handlers $strHandler = new StreamHandler('/var/log/app.log', Logger::DEBUG);
$fcHandler = new FingersCrossedHandler($strHandler, $level);
// Push The Handler And Start Logging $appLog−>pushHandler($fcHandler);
$appLog−>debug('Start Logging!'); $appLog−>emergency('Something Terrible Happened');
Loggers And Handlers
<?php
use Monolog\Logger; use Symfony\Component\EventDispatcher\EventDispatcher;
$dispatcher = new EventDispatcher();
$dispatcher−>addListener( "business.registration.post",
function () use ($busLog) { $busLog−>info("Customer registered");
} );
$dispatcher−>dispatch("business.registration.post");
Event Logging
http://www.sitepoint.com/logging-with-monolog-from-devtools-to-slack/
More usages
Indexing and search engine
Near real-time
Distributed, auto-discover clustering
– AWS Plugin
Elasticsearch
example filter { if [file] == "/var/log/secure" and (
[syslog_message] =~ /Invalid user/ or
[syslog_message] =~ /User root from/ ) {
grok {
add_tag => [ "LOGIN" ]
match => {"syslog_message" => “user %{ WORD:username}
from %{IP:srcip}" }
}
}
}
Logstash
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