Print PHP Call Stack

Php Stack Trace Error Logging

Php Problem Overview

I'm looking for a way to print the call stack in PHP.

Bonus points if the function flushes the IO buffer.

Php Solutions

Solution 1 - Php

Solution 2 - Php

If you want to generate a backtrace, you are looking for debug_backtrace and/or debug_print_backtrace.

The first one will, for instance, get you an array like this one (quoting the manual) :

array(2) {
[0]=>
array(4) {
    ["file"] => string(10) "/tmp/a.php"
    ["line"] => int(10)
    ["function"] => string(6) "a_test"
    ["args"]=>
    array(1) {
      [0] => &string(6) "friend"
    }
}
[1]=>
array(4) {
    ["file"] => string(10) "/tmp/b.php"
    ["line"] => int(2)
    ["args"] =>
    array(1) {
      [0] => string(10) "/tmp/a.php"
    }
    ["function"] => string(12) "include_once"
  }
}

They will apparently not flush the I/O buffer, but you can do that yourself, with flush and/or ob_flush.

(see the manual page of the first one to find out why the "and/or" ;-) )

Solution 3 - Php

Strange that noone posted this way:

debug_print_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS);

This actually prints backtrace without the garbage - just what method was called and where.

Solution 4 - Php

To log the trace

$e = new Exception;
error_log(var_export($e->getTraceAsString(), true));

Thanks @Tobiasz

Solution 5 - Php

Backtrace dumps a whole lot of garbage that you don't need. It takes is very long, difficult to read. All you usuall ever want is "what called what from where?" Here is a simple static function solution. I usually put it in a class called 'debug', which contains all of my debugging utility functions.

class debugUtils {
    public static function callStack($stacktrace) {
        print str_repeat("=", 50) ."\n";
        $i = 1;
        foreach($stacktrace as $node) {
            print "$i. ".basename($node['file']) .":" .$node['function'] ."(" .$node['line'].")\n";
            $i++;
        }
    } 
}

You call it like this:

debugUtils::callStack(debug_backtrace());

And it produces output like this:

==================================================
 1. DatabaseDriver.php::getSequenceTable(169)
 2. ClassMetadataFactory.php::loadMetadataForClass(284)
 3. ClassMetadataFactory.php::loadMetadata(177)
 4. ClassMetadataFactory.php::getMetadataFor(124)
 5. Import.php::getAllMetadata(188)
 6. Command.php::execute(187)
 7. Application.php::run(194)
 8. Application.php::doRun(118)
 9. doctrine.php::run(99)
 10. doctrine::include(4)
==================================================

Solution 6 - Php

If you want a stack trace which looks very similar to how php formats the exception stack trace than use this function I wrote:

function debug_backtrace_string() {
	$stack = '';
	$i = 1;
	$trace = debug_backtrace();
	unset($trace[0]); //Remove call to this function from stack trace
	foreach($trace as $node) {
		$stack .= "#$i ".$node['file'] ."(" .$node['line']."): "; 
		if(isset($node['class'])) {
			$stack .= $node['class'] . "->"; 
		}
		$stack .= $node['function'] . "()" . PHP_EOL;
		$i++;
	}
	return $stack;
}

This will return a stack trace formatted like this:

#1 C:\Inetpub\sitename.com\modules\sponsors\class.php(306): filePathCombine()
#2 C:\Inetpub\sitename.com\modules\sponsors\class.php(294): Process->_deleteImageFile()
#3 C:\Inetpub\sitename.com\VPanel\modules\sponsors\class.php(70): Process->_deleteImage()
#4 C:\Inetpub\sitename.com\modules\sponsors\process.php(24): Process->_delete()

Solution 7 - Php

var_dump(debug_backtrace());

Does that do what you want?

Solution 8 - Php

See debug_print_backtrace. I guess you can call flush afterwards if you want.

Solution 9 - Php

phptrace is a great tool to print PHP stack anytime when you want without installing any extensions.

There are two major function of phptrace: first, print call stack of PHP which need not install anything, second, trace php execution flows which needs to install the extension it supplies.

as follows:

$ ./phptrace -p 3130 -s             # phptrace -p <PID> -s
phptrace 0.2.0 release candidate, published by infra webcore team
process id = 3130
script_filename = /home/xxx/opt/nginx/webapp/block.php
[0x7f27b9a99dc8]  sleep /home/xxx/opt/nginx/webapp/block.php:6
[0x7f27b9a99d08]  say /home/xxx/opt/nginx/webapp/block.php:3
[0x7f27b9a99c50]  run /home/xxx/opt/nginx/webapp/block.php:10

Solution 10 - Php

Use debug_backtrace to get a backtrace of what functions and methods had been called and what files had been included that led to the point where debug_backtrace has been called.

Solution 11 - Php

please take a look at this utils class, may be helpful:

Usage:

<?php
/* first caller */
 Who::callme();

/* list the entire list of calls */
Who::followme();

Source class: https://github.com/augustowebd/utils/blob/master/Who.php

Solution 12 - Php

Walltearer's solution is excellent, particularly if enclosed in a 'pre' tag:

<pre>
<?php debug_print_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS); ?>
</pre>

which sets out the calls on separate lines, neatly numbered

Solution 13 - Php

debug_backtrace()

Solution 14 - Php

You might want to look into debug_backtrace, or perhaps debug_print_backtrace.

Solution 15 - Php

I have adapted Don Briggs's answer above to use internal error logging instead of public printing, which may be your big concern when working on a live server. Also, added few more modifications like option to include full file path instead of basic name (because, there could be files with same name in different paths), and also (for those who require it) a complete node stack output:

class debugUtils {
    public static function callStack($stacktrace) {
        error_log(str_repeat("=", 100));
        $i = 1;
        foreach($stacktrace as $node) {
			// uncomment next line to debug entire node stack
			// error_log(print_r($node, true));
            error_log( $i . '.' . ' file: ' .$node['file'] . ' | ' . 'function: ' . $node['function'] . '(' . ' line: ' . $node['line'] . ')' );
            $i++;
        }
        error_log(str_repeat("=", 100));
    } 
}

// call debug stack
debugUtils::callStack(debug_backtrace());

Solution 16 - Php

If one is just interested in the files called - you can use the following:

print_r(array_column(debug_backtrace(),'file'));

Likewise you can replace file with a different key just to see that data.

Content Type	Original Author	Original Content on Stackoverflow
Question	Justin	View Question on Stackoverflow
Solution 1 - Php	Tobias Cudnik	View Answer on Stackoverflow
Solution 2 - Php	Pascal MARTIN	View Answer on Stackoverflow
Solution 3 - Php	AbstractVoid	View Answer on Stackoverflow
Solution 4 - Php	Sydwell	View Answer on Stackoverflow
Solution 5 - Php	Don Briggs	View Answer on Stackoverflow
Solution 6 - Php	TroySteven	View Answer on Stackoverflow
Solution 7 - Php	brettkelly	View Answer on Stackoverflow
Solution 8 - Php	Martin Geisler	View Answer on Stackoverflow
Solution 9 - Php	renenglish	View Answer on Stackoverflow
Solution 10 - Php	Gumbo	View Answer on Stackoverflow
Solution 11 - Php	augustowebd	View Answer on Stackoverflow
Solution 12 - Php	Geoff Kendall	View Answer on Stackoverflow
Solution 13 - Php	pix0r	View Answer on Stackoverflow
Solution 14 - Php	Rob	View Answer on Stackoverflow
Solution 15 - Php	dev101	View Answer on Stackoverflow
Solution 16 - Php	Antony	View Answer on Stackoverflow