Skip to content

Instantly share code, notes, and snippets.

@cotto
Last active April 11, 2018 23:05
Show Gist options
  • Save cotto/3be895cfb60ce7a26a30f328533413d4 to your computer and use it in GitHub Desktop.
Save cotto/3be895cfb60ce7a26a30f328533413d4 to your computer and use it in GitHub Desktop.
<?php
# originally for use in includes/bootstrap.php in Drupal but intentionally self-contained and suitable for any PHP project
# uses /**/ comments so that it can be squished into a single line for easy copy/pasting
/* intended use: l("debug message"); l(array('foo', $random_object));
/* l() was already taken */
function ll($logged_thing, $no_backtrace = false) {
static $req_id = 0;
if ($req_id == 0) {
/* make it easy to correlate entries within the same request and ensure that $req_id always has the same length so log entries line up nicely */
$req_id = rand(10000, 99999);
}
$logfile = "/tmp/drupal-debug.log";
$preamble = '';
$preamble .= "$req_id ";
$preamble .= "PHP ".phpversion();
$preamble .= ' ';
/* in case we're on a misconfigured machine and need to set this manually */
date_default_timezone_set('America/Los_Angeles');
$preamble .= date('Y-m-d H:i:s');
if (version_compare(PHP_VERSION, '5.4.0') >= 0) {
$backtrace = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2);
}
elseif (version_compare(PHP_VERSION, '5.3.6') >= 0) {
$backtrace = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS);
}
else {
$backtrace = debug_backtrace(true);
}
$file_name = array_key_exists('file', $backtrace[1]) ? $backtrace[1]['file'] : '(unknown file)';
$line_num = array_key_exists('line', $backtrace[1]) ? $backtrace[1]['line'] : '(unknown line)';
$line = $backtrace[1]['function'] ." called in $file_name:$line_num]";
$backtrace_summary = '';
foreach ($backtrace as $frame) {
$class_info = '';
if (array_key_exists('class', $frame)) {
$class_info = $frame['class'] . $frame['type'];
}
$call_site_info = $class_info . $frame['function'];
$call_site_info = str_pad($call_site_info, 40);
$file_name = array_key_exists('file', $frame) ? $frame['file'] : '(unknown file)';
$line_num = array_key_exists('line', $frame) ? $frame['line'] : '(unknown line)';
$backtrace_summary .= "$call_site_info called in $file_name: $line_num\n";
}
$backtrace_summary .= "\n";
$preamble = "[[$preamble $line]]";
$log_msg = '';
if (!is_string($logged_thing)) {
$log_msg = print_r($logged_thing, 1);
}
else {
$log_msg = $logged_thing;
}
$msg = "$preamble $log_msg\n";
if (!$no_backtrace) {
$msg .= "$backtrace_summary\n";
}
file_put_contents($logfile, $msg, FILE_APPEND);
}
/* write to the debug log if recursion is detected */
function rec_check() {
if (version_compare(PHP_VERSION, '5.4.0') >= 0) {
$backtrace = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2);
}
elseif (version_compare(PHP_VERSION, '5.3.6') >= 0) {
$backtrace = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS);
}
else {
$backtrace = debug_backtrace(true);
}
$caller_name = $backtrace[1]['function'];
/* use $i=2 to skip recursion checks against this function and its immediate invocant's stack frames */
for ($i = 2; $i < count($backtrace); $i++) {
$frame = $backtrace[$i];
if (!strcmp($frame['function'], $caller_name)) {
ll("detected recursive call to '$caller_name'");
}
}
}
@cotto
Copy link
Author

cotto commented Apr 11, 2018

I wrote this while debugging a particularly slippery Drupal bug. The bug lives on but the debug printing function was useful enough that I felt bad throwing it away.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment