Logging system in PHP framework, PHP framework logging system_PHP tutorial

Logging system in PHP framework, PHP framework logging system

I am currently working as a PHP back-end developer programmer in a company (our team does not have a front-end, so we will do front-end stuff when doing activities). When I first joined the company, it took me 2 weeks to build a front-end plus back-end program. activities (I remember that I couldn’t do it at the time and had to work overtime for two days on the weekend...). It has been more than 4 months now. I can do a not very complicated activity in an afternoon. Of course, I will consider a lot of things when doing it now. , such as scalability and reusability, because if you do more, you will accumulate a lot of things similar to small plug-ins, so it will be faster. . . . . . But I found that "standing in the requirements and doing the requirements" all day long is very bad. This way I won't learn system and framework things, because I am trapped by trivial requirements and have no time to do some important parts of the framework. , and when your colleagues and boss are used to you doing those things, they will push it to you without hesitation every time they encounter something that has no technical content but has to be done (to be selfish, everyone Programmers are all like me, they all want to master something with technical content, so that they can have a sense of pride as a programmer), and over time you will get used to it... This is really miserable, so I will take it out Take some time to learn the things in the framework and try not to be a simple coder.

^Introduction

Friends who have been exposed to the PHP framework may know the important role of logs in the project. It can help us locate the error location and make the program more friendly (if handled properly, it will not directly throw a big Heap (English (English) only programmers can really move), it will be very convenient during debugging, and can also record some important operations, etc. In short, if a complete project does not have a log system, the development road will be full of thorns, There are potholes and there will definitely be stumbling.

Introduction

To master the PHP logging system, you must first have a thorough understanding of these things.

1. Several functions of php

1 set_exception_handler(callback $exception_handler); //Exception Capture custom handler function registration

1 set_error_handler(callback $error_handler); //Error Capture custom handler function registration

1 register_shutdown_function(callback $callback); //program Abnormal termination error capture handler function registration during execution

These three functions provide developers with a lot of autonomy in error handling control, and they are responsible for recording log information in the logging system.

When an exception occurs in the program, the PHP kernel will throw an exception error and then print the error message to the user. If the exception handling function is registered, the exception thrown by PHP will be forwarded to itself. The defined registered exception catching function contains the processing we need to do and records the error information (including error details and error location). After the function handles the exception, the exception will terminate.

When an error occurs in the program, the error handling function we registered will convert the error information into an error exception object and pass it to the exception handling function, which is the $exception_handler function in the first step.

When a shutdown error occurs during the resumption, the abnormal termination processing function we registered will be executed. This function obtains the error object of the last shutdown through error_get_last(), and then generates an error like the previous part. exception object, pass this object to our registered exception handling function.

As you can see, in fact, whether it is an exception or an error, it converts its own information into the exception information recognized by the exception handling function, and then hands it to the exception handling function for processing. The non-exception information is like makeup. Just like women, the exception handler does not recognize these non-exception information. Only by removing the loading and unloading (the non-exception information itself is converted into exception information, to be precise, it should be thrown), the exception handler will recognize it.

Error handling process in php log system

So now comes the question. These functions usually work with an exception handling library and an error logging library. The exception handling library contains 3 functions to be registered. The logging class library is called in $exception_handler to record and place log files reasonably. The functions mentioned above are generally loaded and registered at the entrance of the program framework, as follows:

The array(class, function) method is used here.

<span>1</span> <span>set_exception_handler</span>(<span>array</span>("Myexception","exceptionHandler"<span>));
</span><span>2</span> <span>set_error_handler</span>(<span>array</span>("Myexception","errorHandler"<span>));
</span><span>3</span> <span>register_shutdown_function</span>(<span>array</span>("Myexception","shutdownHandler"));

2. Logging related libraries

The things introduced in the first part only capture exceptions, errors, and shutdowns. This is only the first step. Next, the captured information must be processed reasonably, such as recording these Log information to the local file system (this operation is in array("Myexception", "exceptionHandler")), where the logging class library is used. (The class library mentioned below draws on the design of the kohana log system).

Japanese-style logging is also very simple. All you need to do is add the information to the end of the file. This is easy to implement. I believe everyone can implement it by themselves, but it is necessary to design a convenient, efficient, The extended logging class library is not that simple. It needs to be summarized and optimized after a long period of practice. The logging class library in the kohana framework is relatively mature, so we can use it here for reference.

I believe that users who have used kohana must be familiar with the logging in the kohana framework. It doesn’t matter if you are not familiar. I will briefly talk about the application/bootstrap.php file in the kohana source code. You can see the following code in lines 109-112:

<span>109</span> <span>/*</span><span>*
</span><span>110</span> <span> * Attach the file write to logging. Multiple writers are supported.
</span><span>111</span>  <span>*/</span>
<span>112</span> Kohana::<span>$log</span>->attach(<span>new</span> Log_File(APPPATH.'logs'));

This is to add a logging object to the log object. Pay attention to the two with olive background. They are different class library instances in kohana. , the logging object is divided into two parts. The first part is the log object, which is used to maintain a list of logging objects. How to understand this? It is actually like a container, which contains one or more logging objects (this is In the second part, these logging objects are actually used to record logs), and there is also an array of error levels to be recorded for each object. They will only be recorded when the error level is met, and will be omitted if not. The following is my own simplified logging method after renaming:

<span>1</span> self::<span>$log</span> = <span>Log</span>::<span>instance();
</span><span>2</span> self::<span>$log</span>->attach(<span>new</span> Logwriter("./data/debug"),<span>Log</span>::<span>DEBUG);
</span><span>3</span> self::<span>$log</span>->attach(<span>new</span> Logwriter("./data/notice"),<span>Log</span>::NOTICE);

In order to better understand here, I named the "container" as Log and the recorded instance as Logwriter. You can see that I easily added two different log types at the program entrance. The first one is Record all errors with error numbers smaller than Log::DEBUG (error level higher than him), and record them under the folder ./data/debug according to the rules. The second one is to record errors with a level equal to or higher than Log::NOTICE. , of course, you can also specify which errors are good in more detail, just pass the array. This is what I think is convenient and fast. We can add error logs and divide them into different log directories according to our needs. Let’s look at a picture below. It will help to understand:

3. Example summary

At this point you should have an overview of the log system, and you can already write a "log system" for use. Let's take a look at my "log system" example. This is the github address, which contains the code and See examples if needed.

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