CODEWITHSUNDEEP
phpmultithreadingloggingwebrequest
Jonas Sourlier
Jonas Sourlier

Reputation: 14435

Get unique worker/thread/process/request ID in PHP

In multi-threaded environments (like most web platforms) I often include some sort of thread ID to the logs of my apps. This enables me to tell exactly what log entry came from which request/thread, when there are multiple requests at once which are simultaneously writing to the same log.

In .NET/C#, this can be done by the formatters of log4net, which by default include the current thread's ManagedThreadId (a number) or Name (a given name). These properties uniquely identify a thread (see for example: How to log correct context with Threadpool threads using log4net?

In PHP, I have not found anything similar (I asked Google, PHP docs and SO). Does it exist?

Upvotes: 16

Views: 13908

Answers (5)

Ian Dunn
Ian Dunn

Reputation: 3680

I've seen getmypid() used for this purpose, but it seems to behave differently on different systems. In some cases the ID is unique to each request, but on others it's shared.

So, you're probably better of going with one of the other answers to ensure portability.

Upvotes: 1

Sven
Sven

Reputation: 70863

Assigning an ID in order to identify logged data from serving a request probably is as simple as creating a UUID version 4 (random) and writing it to every line of the log.

There even is software helping with that: ramsey/uuid, php-middleware/request-id

Adding it to every line of logging is easy when using log4php by putting the UUID to the LoggerMDC data and using an appropriate LogFormatter. With PSR-3 loggers, it might be a bit more complicated, YMMV.

A randomly created UUID will be suitable to identify one single request, and by using that UUID in the HTTP headers of sub requests and in the response, it will even be possible to trace one request across multiple systems and platforms inside the server farm. However, putting it as a header is not the task of any of the packages I mentioned.

Upvotes: 0

gilm
gilm

Reputation: 8050

Up until recently, I used apache_getenv("UNIQUE_ID"), and it worked perfectly with a crc32 or another hash function.

Nowadays I'm just using the following, in order to remove dependency on Apache and this mod.

$uniqueid = sprintf("%08x", abs(crc32($_SERVER['REMOTE_ADDR'] . $_SERVER['REQUEST_TIME'] . $_SERVER['REMOTE_PORT'])));

It's unique enough to understand which logs belong to which request. If you need more precision, you can use other hash functions.

Hope this helps.

Upvotes: 24

Juha Palomäki
Juha Palomäki

Reputation: 27042

PHP does not seem to have a function for this available, but your web server might be able to pass the identifier via environment variables. There is for example an Apache module called "mod_unique_id"[1] which generates a unique identifier for each request and stores it as an environment variables. If the variable is present, it should be visible via $_SERVER['unique_id'] [2]

"Pure PHP" solution could be to write a script that generates suitable random identifier, stores it via define("unique_id", val) and then use auto_prepend_file [3] option in php.ini to include this in every script that executes. This way the unique id would be created when the request starts processing and it would be available during the processing of the request.

Upvotes: 2

CodeCaster
CodeCaster

Reputation: 151604

zend_thread_id():

int zend_thread_id ( void )

This function returns a unique identifier for the current thread.

Although:

This function is only available if PHP has been built with ZTS (Zend Thread Safety) support and debug mode (--enable-debug).

You could also try yo call mysql_thread_id(), when you use that API for your database access (or mysqli::$thread_id when using mysqli).

Upvotes: 7

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