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<?php
/**
* File: UsageStatistics_Source_DbQueriesLog.php
*
* @package W3TC
*/
namespace W3TC;
/**
* Class UsageStatistics_Source_PageCacheLog
*
* PageCache debug log reader - provides data from this logfile
*
* phpcs:disable WordPress.PHP.NoSilencedErrors.Discouraged
* phpcs:disable WordPress.WP.AlternativeFunctions
*/
class UsageStatistics_Source_PageCacheLog {
/**
* Timestamp indicating the start time for log processing.
*
* @var int
*/
private $timestamp_start;
/**
* Current process status used to filter logs.
*
* @var string
*/
private $process_status;
/**
* Column used for sorting the final log entries output.
*
* @var string
*/
private $sort_column;
/**
* Holds URI data parsed from the log file, including count, sum size, sum time, and reasons.
*
* @var array
*/
private $by_uri = array();
/**
* Flag indicating whether more log entries are required to be processed.
*
* @var bool
*/
private $more_log_needed = true;
/**
* Constructor to initialize the class attributes.
*
* @param int $timestamp_start The start timestamp for the log processing.
* @param string $process_status The process status to filter the logs by.
* @param string $sort_column The column to sort the final results by.
*
* @return void
*/
public function __construct( $timestamp_start, $process_status, $sort_column ) {
$this->timestamp_start = $timestamp_start;
$this->process_status = $process_status;
$this->sort_column = $sort_column;
}
/**
* Lists all the parsed log entries, sorted by the specified column.
*
* This method reads the log file, processes it in reverse order, and accumulates the relevant data
* about each URI, such as the count of occurrences, average size, average time taken,
* and unique reasons for the status. It returns a sorted list of the data based on the selected column.
*
* @return array List of log entries, each containing URI, count, average size,
* average time in milliseconds, total time, and reasons.
*
* @throws \Exception If the log file cannot be opened.
*/
public function list_entries() {
$log_filename = Util_Debug::log_filename( 'pagecache' );
$h = @fopen( $log_filename, 'rb' );
if ( ! $h ) {
throw new \Exception(
\esc_html(
sprintf(
// Translators: 1 Log filename.
\__( 'Failed to open pagecache log file %1$s.', 'w3-total-cache' ),
$log_filename
)
)
);
}
fseek( $h, 0, SEEK_END );
$pos = ftell( $h );
$unparsed_head = '';
while ( $pos >= 0 && $this->more_log_needed ) {
$pos -= 8192;
if ( $pos <= 0 ) {
$pos = 0;
}
fseek( $h, $pos );
$s = fread( $h, 8192 );
$unparsed_head = $this->parse_string( $s . $unparsed_head, $pos > 0 );
if ( $pos <= 0 ) {
$this->more_log_needed = false;
}
}
$output = array();
foreach ( $this->by_uri as $uri => $data ) {
$output[] = array(
'uri' => $uri,
'count' => $data['count'],
'avg_size' => (int) ( $data['sum_size'] / $data['count'] ),
'avg_time_ms' => (int) ( $data['sum_time_ms'] / $data['count'] ),
'sum_time_ms' => $data['sum_time_ms'],
'reasons' => $data['reasons'],
);
}
usort(
$output,
function ( $a, $b ) {
return (int) ( $b[ $this->sort_column ] ) - (int) ( $a[ $this->sort_column ] );
}
);
return $output;
}
/**
* Parses the provided string and processes each line of log data.
*
* This method processes the log data in chunks and parses each line for relevant information.
* It will skip the first line if required and handle the raw log string by calling `push_line` for each parsed line.
*
* @param string $s The string to be parsed.
* @param bool $skip_first_line Flag to indicate whether the first line should be skipped.
*
* @return string Unparsed head of the log data that remains after parsing.
*/
private function parse_string( $s, $skip_first_line ) {
$s_length = strlen( $s );
$unparsed_head = '';
$n = 0;
if ( $skip_first_line ) {
for ( ; $n < $s_length; $n++ ) {
$c = substr( $s, $n, 1 );
if ( "\r" === $c || "\n" === $c ) {
$unparsed_head = substr( $s, 0, $n + 1 );
break;
}
}
}
$line_start = $n;
for ( ; $n < $s_length; $n++ ) {
$c = substr( $s, $n, 1 );
if ( "\r" === $c || "\n" === $c ) {
if ( $n > $line_start ) {
$this->push_line( substr( $s, $line_start, $n - $line_start ) );
}
$line_start = $n + 1;
}
}
return $unparsed_head;
}
/**
* Processes and stores the data from a single log line.
*
* This method matches the log line against a regular expression and extracts details such as the URI,
* time taken, size, process status, and the reason. If the log line meets the filter criteria (e.g.,
* matching the process status and timestamp), the relevant information is added to the `$by_uri` attribute.
*
* @param string $line A single line of log data to be processed.
*
* @return void
*/
private function push_line( $line ) {
$matches = null;
preg_match(
'/\[([^>\]]+)\] \[([^>\]]+)\] \[([^>\]]+)\] finished in (\d+) size (\d+) with process status ([^ ]+) reason (.*)/',
$line,
$matches
);
if ( ! $matches ) {
return;
}
$date_string = $matches[1];
$uri = $matches[2];
$time_taken_ms = $matches[4];
$size = $matches[5];
$status = $matches[6];
$reason = $matches[7];
$time = strtotime( $date_string );
// dont read more if we touched entries before timeperiod of collection.
if ( $time < $this->timestamp_start ) {
$this->more_log_needed = false;
}
if ( $status !== $this->process_status ) {
return;
}
if ( ! isset( $this->by_uri[ $uri ] ) ) {
$this->by_uri[ $uri ] = array(
'count' => 0,
'sum_size' => 0,
'sum_time_ms' => 0,
'reasons' => array(),
);
}
++$this->by_uri[ $uri ]['count'];
$this->by_uri[ $uri ]['sum_size'] += $size;
$this->by_uri[ $uri ]['sum_time_ms'] += $time_taken_ms;
if ( ! in_array( $reason, $this->by_uri[ $uri ]['reasons'], true ) ) {
$this->by_uri[ $uri ]['reasons'][] = $reason;
}
}
}