我们在写代码时，都想自己的代码尽可能的不影响现有的代码。, (*1)
或者说，最大化不改动任何代码的情况下，如何嵌入我们的新功能？这是我们常说的「非侵入式」的开发方式。, (*2)
使用「非侵入式」的开发模式，主要在提供第三方插件和功能中最为常见。今天借助「Rollbar」第三方工具来说说如何做到「非侵入式」开发。, (*3)
本文主要能学到:, (*4)
- Laravel Event / Listener 原理；
- Rollbar for Laravel 的使用
- 创建一个 Log to Dingding 群的功能
Laravel Event / Listener 原理
在 Laravel，主要利用 EventServiceProvider 来加载 Events / Listeners:, (*5)
<?php
namespace Illuminate\Events;
use Illuminate\Support\ServiceProvider;
use Illuminate\Contracts\Queue\Factory as QueueFactoryContract;
class EventServiceProvider extends ServiceProvider
{
/**
* Register the service provider.
*
* @return void
*/
public function register()
{
$this->app->singleton('events', function ($app) {
return (new Dispatcher($app))->setQueueResolver(function () use ($app) {
return $app->make(QueueFactoryContract::class);
});
});
}
}
EventServiceProvider 返回的是 Dispatcher 对象。我们看看 Dispatcher 类：, (*6)
<?php
namespace Illuminate\Events;
use Exception;
use ReflectionClass;
use Illuminate\Support\Arr;
use Illuminate\Support\Str;
use Illuminate\Container\Container;
use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Contracts\Broadcasting\ShouldBroadcast;
use Illuminate\Contracts\Events\Dispatcher as DispatcherContract;
use Illuminate\Contracts\Broadcasting\Factory as BroadcastFactory;
use Illuminate\Contracts\Container\Container as ContainerContract;
class Dispatcher implements DispatcherContract
{
/**
* The IoC container instance.
*
* @var \Illuminate\Contracts\Container\Container
*/
protected $container;
/**
* The registered event listeners.
*
* @var array
*/
protected $listeners = [];
/**
* The wildcard listeners.
*
* @var array
*/
protected $wildcards = [];
/**
* The queue resolver instance.
*
* @var callable
*/
protected $queueResolver;
/**
* Create a new event dispatcher instance.
*
* @param \Illuminate\Contracts\Container\Container|null $container
* @return void
*/
public function __construct(ContainerContract $container = null)
{
$this->container = $container ?: new Container;
}
/**
* Register an event listener with the dispatcher.
*
* @param string|array $events
* @param mixed $listener
* @return void
*/
public function listen($events, $listener)
{
foreach ((array) $events as $event) {
if (Str::contains($event, '*')) {
$this->setupWildcardListen($event, $listener);
} else {
$this->listeners[$event][] = $this->makeListener($listener);
}
}
}
...
}
主要作用是绑定 Events 和 Listeners，当 Events触发时，直接执行 Listeners。, (*7)
我们希望 log 除了在本地文件存储输出外，也想把 log 信息实时发到其他平台和渠道上，这时候我们就需要借助 LogServiceProvider 的 events / listeners绑定实现了。现在来看看 LogServiceProvider:, (*8)
<?php
namespace Illuminate\Log;
use Monolog\Logger as Monolog;
use Illuminate\Support\ServiceProvider;
class LogServiceProvider extends ServiceProvider
{
/**
* Register the service provider.
*
* @return void
*/
public function register()
{
$this->app->singleton('log', function () {
return $this->createLogger();
});
}
/**
* Create the logger.
*
* @return \Illuminate\Log\Writer
*/
public function createLogger()
{
$log = new Writer(
new Monolog($this->channel()), $this->app['events']
);
if ($this->app->hasMonologConfigurator()) {
call_user_func($this->app->getMonologConfigurator(), $log->getMonolog());
} else {
$this->configureHandler($log);
}
return $log;
}
...
}
这里将 $this->app['events'] 也就是 Dispatcher 传入，用户事件的注册：, (*9)
/**
* Register a new callback handler for when a log event is triggered.
*
* @param \Closure $callback
* @return void
*
* @throws \RuntimeException
*/
public function listen(Closure $callback)
{
if (! isset($this->dispatcher)) {
throw new RuntimeException('Events dispatcher has not been set.');
}
$this->dispatcher->listen(MessageLogged::class, $callback);
}
有了 ServiceProvider 和 listen 就可以做到「非入侵」开发了。, (*10)
Rollbar
Rollbar error monitoring integration for Laravel projects. This library adds a listener to Laravel's logging component. Laravel's session information will be sent in to Rollbar, as well as some other helpful information such as 'environment', 'server', and 'session'., (*11)
参考：https://docs.rollbar.com/docs/laravel, (*12)
简单使用
使用该工具，只要在其官网注册账号，并产生一个 access token 即可, (*13)
安装该工具，也只需要简单的两步：, (*14)
composer require rollbar/rollbar-laravel
// .env
ROLLBAR_TOKEN=[your Rollbar project access token]
// 如果 < Laravel 5.5，则需要在 app.php 中添加
Rollbar\Laravel\RollbarServiceProvider::class,
测试，只要有 Log 输出，rollbar 后台都可以收到信息，方便查看，而再也不需要去看 log 文件了。, (*15)
, (*16)
剖析实现原理
我们来看看 rollbar 是不是我们所设想的那样实现的？, (*17)
, (*18)
我们先看看 RollbarServiceProvider, (*19)
<?php namespace Rollbar\Laravel;
use Illuminate\Support\ServiceProvider;
use InvalidArgumentException;
use Rollbar\Rollbar;
use Rollbar\Laravel\RollbarLogHandler;
class RollbarServiceProvider extends ServiceProvider
{
/**
* Indicates if loading of the provider is deferred.
*
* @var bool
*/
protected $defer = false;
/**
* Bootstrap the application events.
*/
public function boot()
{
// Don't boot rollbar if it is not configured.
if ($this->stop() === true) {
return;
}
$app = $this->app;
// Listen to log messages.
$app['log']->listen(function () use ($app) {
$args = func_get_args();
// Laravel 5.4 returns a MessageLogged instance only
if (count($args) == 1) {
$level = $args[0]->level;
$message = $args[0]->message;
$context = $args[0]->context;
} else {
$level = $args[0];
$message = $args[1];
$context = $args[2];
}
$app['Rollbar\Laravel\RollbarLogHandler']->log($level, $message, $context);
});
}
/**
* Register the service provider.
*/
public function register()
{
// Don't register rollbar if it is not configured.
if ($this->stop() === true) {
return;
}
$app = $this->app;
$this->app->singleton('Rollbar\RollbarLogger', function ($app) {
$defaults = [
'environment' => $app->environment(),
'root' => base_path(),
'handle_exception' => true,
'handle_error' => true,
'handle_fatal' => true,
];
$config = array_merge($defaults, $app['config']->get('services.rollbar', []));
$config['access_token'] = getenv('ROLLBAR_TOKEN') ?: $app['config']->get('services.rollbar.access_token');
if (empty($config['access_token'])) {
throw new InvalidArgumentException('Rollbar access token not configured');
}
$handleException = (bool) array_pull($config, 'handle_exception');
$handleError = (bool) array_pull($config, 'handle_error');
$handleFatal = (bool) array_pull($config, 'handle_fatal');
Rollbar::init($config, $handleException, $handleError, $handleFatal);
return Rollbar::logger();
});
$this->app->singleton('Rollbar\Laravel\RollbarLogHandler', function ($app) {
$level = getenv('ROLLBAR_LEVEL') ?: $app['config']->get('services.rollbar.level', 'debug');
return new RollbarLogHandler($app['Rollbar\RollbarLogger'], $app, $level);
});
}
/**
* Check if we should prevent the service from registering
*
* @return boolean
*/
public function stop()
{
$level = getenv('ROLLBAR_LEVEL') ?: $this->app->config->get('services.rollbar.level', null);
$token = getenv('ROLLBAR_TOKEN') ?: $this->app->config->get('services.rollbar.access_token', null);
$hasToken = empty($token) === false;
return $hasToken === false || $level === 'none';
}
}
这个比较好理解，先利用 register 注册两个 singleton，然后在 boot 方法中，注册 listener, (*20)
$app['log']->listen(function () use ($app){});
其中 $app['log']，就是我们的上文说的 LogServiceProvider，将 listener 注册到 EventServiceProvider 中。, (*21)
$this->dispatcher->listen(MessageLogged::class, $callback);
最后我们看看 Rollbar facades 返回的是：RollbarLogHandler 对象, (*22)
<?php namespace Rollbar\Laravel\Facades;
use Illuminate\Support\Facades\Facade;
class Rollbar extends Facade
{
/**
* Get a schema builder instance for the default connection.
*
* @return \Rollbar\Laravel\RollbarLogHandler
*/
protected static function getFacadeAccessor()
{
return 'Rollbar\Laravel\RollbarLogHandler';
}
}
看看 RollbarLogHandler 实现，也主要是将 log 信息反馈到Rollbar 中，此处不做分析了。, (*23)
模拟实现
通过对 Rollbar 简单的分析，就会发现原来通过简单 Listener，不用改现在的任何功能和代码，就能实现将 log 实时发到你想接收的地方。, (*24)
所以我们可以尝试也写一个这样的功能，将 log 信息发到钉钉上。, (*25)
好了，我们开始写 Log2Dingding 插件。, (*26)
根据之前的文章我们可以很方便的组织好插件结构:, (*27)
, (*28)
composer.json 设置:, (*29)
{
"name": "fanly/log2dingding",
"description": "Laravel Log to DingDing",
"license": "MIT",
"authors": [
{
"name": "fanly",
"email": "yemeishu@126.com"
}
],
"require": {},
"extra": {
"laravel": {
"providers": [
"Fanly\\Log2dingding\\FanlyLog2dingdingServiceProvider"
]
}
},
"autoload": {
"psr-4": {
"Fanly\\Log2dingding\\": "src/"
}
}
}
我们定义 ServiceProvider:, (*30)
<?php
/**
* User: yemeishu
* Date: 2018/5/13
* Time: 下午2:56
*/
namespace Fanly\Log2dingding;
use Fanly\Log2dingding\Dingtalk\Messager;
use Illuminate\Support\ServiceProvider;
use Fanly\Log2dingding\Support\Client;
class FanlyLog2dingdingServiceProvider extends ServiceProvider {
protected function registerFacade()
{
// Don't register rollbar if it is not configured.
if ($this->stop() === true) {
return;
}
$this->app->singleton('fanlylog2dd', function ($app) {
$config['access_token'] = getenv('FANLYLOG_TOKEN') ?: $app['config']->get('services.fanly.log2dd.access_token');
if (empty($config['access_token'])) {
throw new InvalidArgumentException('log2dd access token not configured');
}
return (new Messager(new Client()))->accessToken($config['access_token']);
});
}
/**
* Bootstrap the application services.
*/
public function boot()
{
// Don't boot rollbar if it is not configured.
if ($this->stop() === true) {
return;
}
$app = $this->app;
// Listen to log messages.
$app['log']->listen(function () use ($app) {
$args = func_get_args();
// Laravel 5.4 returns a MessageLogged instance only
if (count($args) == 1) {
$level = $args[0]->level;
$message = $args[0]->message;
$context = $args[0]->context;
} else {
$level = $args[0];
$message = $args[1];
$context = $args[2];
}
$app['fanlylog2dd']->message("[ $level ] $message\n".implode($context))->send();
});
}
/**
* Register the application services.
*/
public function register()
{
$this->registerFacade();
}
private function stop()
{
$level = getenv('FANLYLOG_LEVEL') ?: $this->app->config->get('services.rollbar.level', null);
$token = getenv('FANLYLOG_TOKEN') ?: $this->app->config->get('services.rollbar.access_token', null);
$hasToken = empty($token) === false;
return $hasToken === false || $level === 'none';
}
}
我们主要是创建一个发钉钉消息的单例，然后再注册 listener，只要获取 log 信息，就发送信息到钉钉上。, (*31)
测试一下：, (*32)
, (*33)
总结
最后做成插件，和 Rollbar 一样，引入：, (*34)
composer require "fanly/log2dingding"
// .env
FANLYLOG_TOKEN=56331868f7056a3e645e7dba034c5550e7af***
同样的，其他信息都不需要设置，跑一个测试：, (*35)
, (*36)
Laravel 框架的一大好处在于，可以以友好的方式实现我们「非入侵」开发，只要借助「ServiceProvider」和「Events/Listner」，就可以扩展我们的功能。, (*37)
参考, (*38)
Wallogit.com
fanly