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MDL-68874 dml: Add SQL stacktrace debugging mode
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brendanheywood committed Jul 15, 2020
1 parent ee23a8c commit ef4145d
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Showing 5 changed files with 203 additions and 0 deletions.
7 changes: 7 additions & 0 deletions admin/settings/development.php
Expand Up @@ -41,6 +41,13 @@
$temp->add(new admin_setting_configcheckbox('debugdisplay', new lang_string('debugdisplay', 'admin'), new lang_string('configdebugdisplay', 'admin'), ini_get_bool('display_errors')));
$temp->add(new admin_setting_configcheckbox('perfdebug', new lang_string('perfdebug', 'admin'), new lang_string('configperfdebug', 'admin'), '7', '15', '7'));
$temp->add(new admin_setting_configcheckbox('debugstringids', new lang_string('debugstringids', 'admin'), new lang_string('debugstringids_desc', 'admin'), 0));
$temp->add(new admin_setting_configselect('debugsqltrace',
new lang_string('debugsqltrace', 'admin'),
new lang_string('debugsqltrace_desc', 'admin'), 0, array(
0 => new lang_string('disabled', 'admin'),
1 => new lang_string('debugsqltrace1', 'admin'),
2 => new lang_string('debugsqltrace2', 'admin'),
100 => new lang_string('debugsqltrace100', 'admin'))));
$temp->add(new admin_setting_configcheckbox('debugvalidators', new lang_string('debugvalidators', 'admin'), new lang_string('configdebugvalidators', 'admin'), 0));
$temp->add(new admin_setting_configcheckbox('debugpageinfo', new lang_string('debugpageinfo', 'admin'), new lang_string('configdebugpageinfo', 'admin'), 0));
$ADMIN->add('development', $temp);
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5 changes: 5 additions & 0 deletions lang/en/admin.php
Expand Up @@ -462,6 +462,11 @@
$string['debugnone'] = 'NONE: Do not show any errors or warnings';
$string['debugnormal'] = 'NORMAL: Show errors, warnings and notices';
$string['debugpageinfo'] = 'Show page information';
$string['debugsqltrace'] = 'Show origin of SQL calls';
$string['debugsqltrace1'] = 'Show only a single calling line';
$string['debugsqltrace2'] = 'Show 2 lines of stack trace';
$string['debugsqltrace100'] = 'Show full stack trace';
$string['debugsqltrace_desc'] = 'If enabled adds either partial or full PHP stacktrace into the SQL as a comment';
$string['debugstringids'] = 'Show origin of languages strings';
$string['debugstringids_desc'] = 'If enabled, language string components and identifiers are displayed when ?strings=1 or &strings=1 is appended to the page URL.';
$string['debugvalidators'] = 'Show validator links';
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47 changes: 47 additions & 0 deletions lib/dml/moodle_database.php
Expand Up @@ -889,6 +889,9 @@ public function fix_sql_params($sql, array $params=null) {
// convert table names
$sql = $this->fix_table_names($sql);

// Optionally add debug trace to sql as a comment.
$sql = $this->add_sql_debugging($sql);

// cast booleans to 1/0 int and detect forbidden objects
foreach ($params as $key => $value) {
$this->detect_objects($value);
Expand Down Expand Up @@ -1030,6 +1033,50 @@ public function fix_sql_params($sql, array $params=null) {
}
}

/**
* Add an SQL comment to trace all sql calls back to the calling php code
* @param string $sql Original sql
* @return string Instrumented sql
*/
protected function add_sql_debugging(string $sql): string {
global $CFG;

if (!property_exists($CFG, 'debugsqltrace')) {
return $sql;
}

$level = $CFG->debugsqltrace;

if (empty($level)) {
return $sql;
}

$callers = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS);

// Ignore moodle_database internals.
$callers = array_filter($callers, function($caller) {
return empty($caller['class']) || $caller['class'] != 'moodle_database';
});

$callers = array_slice($callers, 0, $level);

$text = trim(format_backtrace($callers, true));

// Convert all linebreaks to SQL comments, optionally
// also eating any * formatting.
$text = preg_replace("/(^|\n)\*?\s*/", "\n-- ", $text);

// Convert all ? to 'unknown' in the sql coment so these don't get
// caught by fix_sql_params().
$text = str_replace('?', 'unknown', $text);

// Convert tokens like :test to ::test for the same reason.
$text = preg_replace('/(?<!:):[a-z][a-z0-9_]*/', ':\0', $text);

return $sql . $text;
}


/**
* Ensures that limit params are numeric and positive integers, to be passed to the database.
* We explicitly treat null, '' and -1 as 0 in order to provide compatibility with how limit
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49 changes: 49 additions & 0 deletions lib/dml/tests/dml_test.php
Expand Up @@ -438,6 +438,55 @@ public function test_fix_sql_params() {
$this->assertSame(array_values($params), array_values($inparams));
}

/**
* Test the database debugging as SQL comment.
*/
public function test_add_sql_debugging() {
global $CFG;
$DB = $this->tdb;

require_once($CFG->dirroot . '/lib/dml/tests/fixtures/test_dml_sql_debugging_fixture.php');
$fixture = new test_dml_sql_debugging_fixture($this);

$sql = "SELECT * FROM {users}";

$out = $fixture->four($sql);

$CFG->debugsqltrace = 0;
$this->assertEquals("SELECT * FROM {users}", $out);

$CFG->debugsqltrace = 1;
$out = $fixture->four($sql);
$expected = <<<EOD
SELECT * FROM {users}
-- line 65 of /lib/dml/tests/fixtures/test_dml_sql_debugging_fixture.php: call to ReflectionMethod->invoke()
EOD;
$this->assertEquals($expected, $out);

$CFG->debugsqltrace = 2;
$out = $fixture->four($sql);
$expected = <<<EOD
SELECT * FROM {users}
-- line 65 of /lib/dml/tests/fixtures/test_dml_sql_debugging_fixture.php: call to ReflectionMethod->invoke()
-- line 74 of /lib/dml/tests/fixtures/test_dml_sql_debugging_fixture.php: call to test_dml_sql_debugging_fixture->one()
EOD;
$this->assertEquals($expected, $out);

$CFG->debugsqltrace = 5;
$out = $fixture->four($sql);
$expected = <<<EOD
SELECT * FROM {users}
-- line 65 of /lib/dml/tests/fixtures/test_dml_sql_debugging_fixture.php: call to ReflectionMethod->invoke()
-- line 74 of /lib/dml/tests/fixtures/test_dml_sql_debugging_fixture.php: call to test_dml_sql_debugging_fixture->one()
-- line 83 of /lib/dml/tests/fixtures/test_dml_sql_debugging_fixture.php: call to test_dml_sql_debugging_fixture->two()
-- line 92 of /lib/dml/tests/fixtures/test_dml_sql_debugging_fixture.php: call to test_dml_sql_debugging_fixture->three()
-- line 476 of /lib/dml/tests/dml_test.php: call to test_dml_sql_debugging_fixture->four()
EOD;
$this->assertEquals($expected, $out);

$CFG->debugsqltrace = 0;
}

public function test_strtok() {
// Strtok was previously used by bound emulation, make sure it is not used any more.
$DB = $this->tdb;
Expand Down
95 changes: 95 additions & 0 deletions lib/dml/tests/fixtures/test_dml_sql_debugging_fixture.php
@@ -0,0 +1,95 @@
<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle. If not, see <http://www.gnu.org/licenses/>.

/**
* Test SQL debugging fixture
*
* @package core
* @category dml
* @copyright 2020 Brendan Heywood <brendan@catalyst-au.net>
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/

defined('MOODLE_INTERNAL') || die();

/**
* Test SQL debugging fixture
*
* @package core
* @category dml
* @copyright 2020 Brendan Heywood <brendan@catalyst-au.net>
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class test_dml_sql_debugging_fixture {
/** @var db handle */
private $db;

/**
* constructor
* @param testcase $testcase test object
*/
public function __construct($testcase) {
$this->db = $testcase->getMockBuilder(\moodle_database::class)
->getMockForAbstractClass();
}

/**
* Get db handle
* @return a db handle
*/
public function get_mock() {
return $this->db;
}

/**
* Test caller in stacktrace
* @param string $sql original sql
* @return string sql with comments
*/
public function one(string $sql) {
$method = new \ReflectionMethod($this->db, 'add_sql_debugging');
$method->setAccessible(true);
return $method->invoke($this->db, $sql);
}

/**
* Test caller in stacktrace
* @param string $sql original sql
* @return string sql with comments
*/
public function two(string $sql) {
return $this->one($sql);
}

/**
* Test caller in stacktrace
* @param string $sql original sql
* @return string sql with comments
*/
public function three(string $sql) {
return $this->two($sql);
}

/**
* Test caller in stacktrace
* @param string $sql original sql
* @return string sql with comments
*/
public function four(string $sql) {
return $this->three($sql);
}

}

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