first commit

lib/mlbackend/python/classes/privacy/provider.php

@@ -0,0 +1,46 @@
+<?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/>.
+
+/**
+ * Privacy Subsystem implementation for mlbackend_python.
+ *
+ * @package    mlbackend_python
+ * @copyright  2018 David Monllao
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace mlbackend_python\privacy;
+
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * Privacy Subsystem for mlbackend_python implementing null_provider.
+ *
+ * @copyright  2018 David Monllao
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class provider implements \core_privacy\local\metadata\null_provider {
+
+    /**
+     * Get the language string identifier with the component's language
+     * file to explain why this plugin stores no data.
+     *
+     * @return  string
+     */
+    public static function get_reason(): string {
+        return 'privacy:metadata';
+    }
+}

lib/mlbackend/python/classes/processor.php

@@ -0,0 +1,747 @@
+<?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/>.
+
+/**
+ * Python predictions processor
+ *
+ * @package   mlbackend_python
+ * @copyright 2016 David Monllao {@link http://www.davidmonllao.com}
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace mlbackend_python;
+
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * Python predictions processor.
+ *
+ * @package   mlbackend_python
+ * @copyright 2016 David Monllao {@link http://www.davidmonllao.com}
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class processor implements  \core_analytics\classifier, \core_analytics\regressor, \core_analytics\packable {
+
+    /**
+     * The required version of the python package that performs all calculations.
+     */
+    const REQUIRED_PIP_PACKAGE_VERSION = '3.0.5';
+
+    /**
+     * The python package is installed in a server.
+     * @var bool
+     */
+    protected $useserver;
+
+    /**
+     * The path to the Python bin.
+     *
+     * @var string
+     */
+    protected $pathtopython;
+
+    /**
+     * Remote server host
+     * @var string
+     */
+    protected $host;
+
+    /**
+     * Remote server port
+     * @var int
+     */
+    protected $port;
+
+    /**
+     * Whether to use http or https.
+     * @var bool
+     */
+    protected $secure;
+
+    /**
+     * Server username.
+     * @var string
+     */
+    protected $username;
+
+    /**
+     * Server password for $this->username.
+     * @var string
+     */
+    protected $password;
+
+    /**
+     * The constructor.
+     *
+     */
+    public function __construct() {
+        global $CFG;
+
+        $config = get_config('mlbackend_python');
+
+        $this->useserver = !empty($config->useserver);
+
+        if (!$this->useserver) {
+            // Set the python location if there is a value.
+            if (!empty($CFG->pathtopython)) {
+                $this->pathtopython = $CFG->pathtopython;
+            }
+        } else {
+            $this->host = $config->host ?? '';
+            $this->port = $config->port ?? '';
+            $this->secure = $config->secure ?? false;
+            $this->username = $config->username ?? '';
+            $this->password = $config->password ?? '';
+        }
+    }
+
+    /**
+     * Is the plugin ready to be used?.
+     *
+     * @return bool|string Returns true on success, a string detailing the error otherwise
+     */
+    public function is_ready() {
+
+        if (!$this->useserver) {
+            return $this->is_webserver_ready();
+        } else {
+            return $this->is_python_server_ready();
+        }
+    }
+
+    /**
+     * Checks if the python package is available in the web server executing this script.
+     *
+     * @return bool|string Returns true on success, a string detailing the error otherwise
+     */
+    protected function is_webserver_ready() {
+        if (empty($this->pathtopython)) {
+            $settingurl = new \moodle_url('/admin/settings.php', array('section' => 'systempaths'));
+            return get_string('pythonpathnotdefined', 'mlbackend_python', $settingurl->out());
+        }
+
+        // Check the installed pip package version.
+        $cmd = "{$this->pathtopython} -m moodlemlbackend.version";
+
+        $output = null;
+        $exitcode = null;
+        // Execute it sending the standard error to $output.
+        $result = exec($cmd . ' 2>&1', $output, $exitcode);
+
+        if ($exitcode != 0) {
+            return get_string('pythonpackagenotinstalled', 'mlbackend_python', $cmd);
+        }
+
+        $vercheck = self::check_pip_package_version($result);
+        return $this->version_check_return($result, $vercheck);
+    }
+
+    /**
+     * Checks if the server can be accessed.
+     *
+     * @return bool|string True or an error string.
+     */
+    protected function is_python_server_ready() {
+
+        if (empty($this->host) || empty($this->port) || empty($this->username) || empty($this->password)) {
+            return get_string('errornoconfigdata', 'mlbackend_python');
+        }
+
+        // Connection is allowed to use 'localhost' and other potentially blocked hosts/ports.
+        $curl = new \curl(['ignoresecurity' => true]);
+        $responsebody = $curl->get($this->get_server_url('version')->out(false));
+        if ($curl->info['http_code'] !== 200) {
+            return get_string('errorserver', 'mlbackend_python', $this->server_error_str($curl->info['http_code'], $responsebody));
+        }
+
+        $vercheck = self::check_pip_package_version($responsebody);
+        return $this->version_check_return($responsebody, $vercheck);
+
+    }
+
+    /**
+     * Delete the model version output directory.
+     *
+     * @throws \moodle_exception
+     * @param string $uniqueid
+     * @param string $modelversionoutputdir
+     * @return null
+     */
+    public function clear_model($uniqueid, $modelversionoutputdir) {
+        if (!$this->useserver) {
+            remove_dir($modelversionoutputdir);
+        } else {
+            // Use the server.
+
+            $url = $this->get_server_url('deletemodel');
+            list($responsebody, $httpcode) = $this->server_request($url, 'post', ['uniqueid' => $uniqueid]);
+        }
+    }
+
+    /**
+     * Delete the model output directory.
+     *
+     * @throws \moodle_exception
+     * @param string $modeloutputdir
+     * @param string $uniqueid
+     * @return null
+     */
+    public function delete_output_dir($modeloutputdir, $uniqueid) {
+        if (!$this->useserver) {
+            remove_dir($modeloutputdir);
+        } else {
+
+            $url = $this->get_server_url('deletemodel');
+            list($responsebody, $httpcode) = $this->server_request($url, 'post', ['uniqueid' => $uniqueid]);
+        }
+    }
+
+    /**
+     * Trains a machine learning algorithm with the provided dataset.
+     *
+     * @param string $uniqueid
+     * @param \stored_file $dataset
+     * @param string $outputdir
+     * @return \stdClass
+     */
+    public function train_classification($uniqueid, \stored_file $dataset, $outputdir) {
+
+        if (!$this->useserver) {
+            // Use the local file system.
+
+            list($result, $exitcode) = $this->exec_command('training', [$uniqueid, $outputdir,
+                $this->get_file_path($dataset)], 'errornopredictresults');
+
+        } else {
+            // Use the server.
+
+            $requestparams = ['uniqueid' => $uniqueid, 'dirhash' => $this->hash_dir($outputdir),
+                'dataset' => $dataset];
+
+            $url = $this->get_server_url('training');
+            list($result, $httpcode) = $this->server_request($url, 'post', $requestparams);
+        }
+
+        if (!$resultobj = json_decode($result)) {
+            throw new \moodle_exception('errorpredictwrongformat', 'analytics', '', json_last_error_msg());
+        }
+
+        if ($resultobj->status != 0) {
+            $resultobj = $this->format_error_info($resultobj);
+        }
+
+        return $resultobj;
+    }
+
+    /**
+     * Classifies the provided dataset samples.
+     *
+     * @param string $uniqueid
+     * @param \stored_file $dataset
+     * @param string $outputdir
+     * @return \stdClass
+     */
+    public function classify($uniqueid, \stored_file $dataset, $outputdir) {
+
+        if (!$this->useserver) {
+            // Use the local file system.
+
+            list($result, $exitcode) = $this->exec_command('prediction', [$uniqueid, $outputdir,
+                $this->get_file_path($dataset)], 'errornopredictresults');
+
+        } else {
+            // Use the server.
+
+            $requestparams = ['uniqueid' => $uniqueid, 'dirhash' => $this->hash_dir($outputdir),
+                'dataset' => $dataset];
+
+            $url = $this->get_server_url('prediction');
+            list($result, $httpcode) = $this->server_request($url, 'post', $requestparams);
+        }
+
+        if (!$resultobj = json_decode($result)) {
+            throw new \moodle_exception('errorpredictwrongformat', 'analytics', '', json_last_error_msg());
+        }
+
+        if ($resultobj->status != 0) {
+            $resultobj = $this->format_error_info($resultobj);
+        }
+
+        return $resultobj;
+    }
+
+    /**
+     * Evaluates this processor classification model using the provided supervised learning dataset.
+     *
+     * @param string $uniqueid
+     * @param float $maxdeviation
+     * @param int $niterations
+     * @param \stored_file $dataset
+     * @param string $outputdir
+     * @param  string $trainedmodeldir
+     * @return \stdClass
+     */
+    public function evaluate_classification($uniqueid, $maxdeviation, $niterations, \stored_file $dataset,
+            $outputdir, $trainedmodeldir) {
+        global $CFG;
+
+        if (!$this->useserver) {
+            // Use the local file system.
+
+            $datasetpath = $this->get_file_path($dataset);
+
+            $params = [$uniqueid, $outputdir, $datasetpath, \core_analytics\model::MIN_SCORE,
+                $maxdeviation, $niterations];
+
+            if ($trainedmodeldir) {
+                $params[] = $trainedmodeldir;
+            }
+
+            list($result, $exitcode) = $this->exec_command('evaluation', $params, 'errornopredictresults');
+            if (!$resultobj = json_decode($result)) {
+                throw new \moodle_exception('errorpredictwrongformat', 'analytics', '', json_last_error_msg());
+            }
+
+        } else {
+            // Use the server.
+
+            $requestparams = ['uniqueid' => $uniqueid, 'minscore' => \core_analytics\model::MIN_SCORE,
+                'maxdeviation' => $maxdeviation, 'niterations' => $niterations,
+                'dirhash' => $this->hash_dir($outputdir), 'dataset' => $dataset];
+
+            if ($trainedmodeldir) {
+                $requestparams['trainedmodeldirhash'] = $this->hash_dir($trainedmodeldir);
+            }
+
+            $url = $this->get_server_url('evaluation');
+            list($result, $httpcode) = $this->server_request($url, 'post', $requestparams);
+
+            if (!$resultobj = json_decode($result)) {
+                throw new \moodle_exception('errorpredictwrongformat', 'analytics', '', json_last_error_msg());
+            }
+
+            // We need an extra request to get the resources generated during the evaluation process.
+
+            // Directory to temporarly store the evaluation log zip returned by the server.
+            $evaluationtmpdir = make_request_directory();
+            $evaluationzippath = $evaluationtmpdir . DIRECTORY_SEPARATOR . 'evaluationlog.zip';
+
+            $requestparams = ['uniqueid' => $uniqueid, 'dirhash' => $this->hash_dir($outputdir),
+            'runid' => $resultobj->runid];
+
+            $url = $this->get_server_url('evaluationlog');
+            list($result, $httpcode) = $this->server_request($url, 'download_one', $requestparams,
+                ['filepath' => $evaluationzippath]);
+
+            $rundir = $outputdir . DIRECTORY_SEPARATOR . 'logs' . DIRECTORY_SEPARATOR . $resultobj->runid;
+            if (!mkdir($rundir, $CFG->directorypermissions, true)) {
+                throw new \moodle_exception('errorexportmodelresult', 'analytics');
+            }
+
+            $zip = new \zip_packer();
+            $success = $zip->extract_to_pathname($evaluationzippath, $rundir, null, null, true);
+            if (!$success) {
+                $a = 'The evaluation files can not be exported to ' . $rundir;
+                throw new \moodle_exception('errorpredictionsprocessor', 'analytics', '', $a);
+            }
+
+            $resultobj->dir = $rundir;
+        }
+
+        $resultobj = $this->add_extra_result_info($resultobj);
+
+        return $resultobj;
+    }
+
+    /**
+     * Exports the machine learning model.
+     *
+     * @throws \moodle_exception
+     * @param  string $uniqueid  The model unique id
+     * @param  string $modeldir  The directory that contains the trained model.
+     * @return string            The path to the directory that contains the exported model.
+     */
+    public function export(string $uniqueid, string $modeldir): string {
+
+        $exporttmpdir = make_request_directory();
+
+        if (!$this->useserver) {
+            // Use the local file system.
+
+            // We include an exporttmpdir as we want to be sure that the file is not deleted after the
+            // python process finishes.
+            list($exportdir, $exitcode) = $this->exec_command('export', [$uniqueid, $modeldir, $exporttmpdir],
+                'errorexportmodelresult');
+
+            if ($exitcode != 0) {
+                throw new \moodle_exception('errorexportmodelresult', 'analytics');
+            }
+
+        } else {
+            // Use the server.
+
+            $requestparams = ['uniqueid' => $uniqueid, 'dirhash' => $this->hash_dir($modeldir)];
+
+            $exportzippath = $exporttmpdir . DIRECTORY_SEPARATOR . 'export.zip';
+            $url = $this->get_server_url('export');
+            list($result, $httpcode) = $this->server_request($url, 'download_one', $requestparams,
+                ['filepath' => $exportzippath]);
+
+            $exportdir = make_request_directory();
+            $zip = new \zip_packer();
+            $success = $zip->extract_to_pathname($exportzippath, $exportdir, null, null, true);
+            if (!$success) {
+                throw new \moodle_exception('errorexportmodelresult', 'analytics');
+            }
+        }
+
+        return $exportdir;
+    }
+
+    /**
+     * Imports the provided machine learning model.
+     *
+     * @param  string $uniqueid The model unique id
+     * @param  string $modeldir  The directory that will contain the trained model.
+     * @param  string $importdir The directory that contains the files to import.
+     * @return bool Success
+     */
+    public function import(string $uniqueid, string $modeldir, string $importdir): bool {
+
+        if (!$this->useserver) {
+            // Use the local file system.
+
+            list($result, $exitcode) = $this->exec_command('import', [$uniqueid, $modeldir, $importdir],
+                'errorimportmodelresult');
+
+            if ($exitcode != 0) {
+                throw new \moodle_exception('errorimportmodelresult', 'analytics');
+            }
+
+        } else {
+            // Use the server.
+
+            // Zip the $importdir to send a single file.
+            $importzipfile = $this->zip_dir($importdir);
+            if (!$importzipfile) {
+                // There was an error zipping the directory.
+                throw new \moodle_exception('errorimportmodelresult', 'analytics');
+            }
+
+            $requestparams = ['uniqueid' => $uniqueid, 'dirhash' => $this->hash_dir($modeldir),
+                'importzip' => curl_file_create($importzipfile, null, 'import.zip')];
+            $url = $this->get_server_url('import');
+            list($result, $httpcode) = $this->server_request($url, 'post', $requestparams);
+        }
+
+        return (bool)$result;
+    }
+
+    /**
+     * Train this processor regression model using the provided supervised learning dataset.
+     *
+     * @throws new \coding_exception
+     * @param string $uniqueid
+     * @param \stored_file $dataset
+     * @param string $outputdir
+     * @return \stdClass
+     */
+    public function train_regression($uniqueid, \stored_file $dataset, $outputdir) {
+        throw new \coding_exception('This predictor does not support regression yet.');
+    }
+
+    /**
+     * Estimates linear values for the provided dataset samples.
+     *
+     * @throws new \coding_exception
+     * @param string $uniqueid
+     * @param \stored_file $dataset
+     * @param mixed $outputdir
+     * @return void
+     */
+    public function estimate($uniqueid, \stored_file $dataset, $outputdir) {
+        throw new \coding_exception('This predictor does not support regression yet.');
+    }
+
+    /**
+     * Evaluates this processor regression model using the provided supervised learning dataset.
+     *
+     * @throws new \coding_exception
+     * @param string $uniqueid
+     * @param float $maxdeviation
+     * @param int $niterations
+     * @param \stored_file $dataset
+     * @param string $outputdir
+     * @param  string $trainedmodeldir
+     * @return \stdClass
+     */
+    public function evaluate_regression($uniqueid, $maxdeviation, $niterations, \stored_file $dataset,
+            $outputdir, $trainedmodeldir) {
+        throw new \coding_exception('This predictor does not support regression yet.');
+    }
+
+    /**
+     * Returns the path to the dataset file.
+     *
+     * @param \stored_file $file
+     * @return string
+     */
+    protected function get_file_path(\stored_file $file) {
+        // From moodle filesystem to the local file system.
+        // This is not ideal, but there is no read access to moodle filesystem files.
+        return $file->copy_content_to_temp('core_analytics');
+    }
+
+    /**
+     * Check that the given package version can be used and return the error status.
+     *
+     * When evaluating the version, we assume the sematic versioning scheme as described at
+     * https://semver.org/.
+     *
+     * @param string $actual The actual Python package version
+     * @param string $required The required version of the package
+     * @return int -1 = actual version is too low, 1 = actual version too high, 0 = actual version is ok
+     */
+    public static function check_pip_package_version($actual, $required = self::REQUIRED_PIP_PACKAGE_VERSION) {
+
+        if (empty($actual)) {
+            return -1;
+        }
+
+        if (version_compare($actual, $required, '<')) {
+            return -1;
+        }
+
+        $parts = explode('.', $required);
+        $requiredapiver = reset($parts);
+
+        $parts = explode('.', $actual);
+        $actualapiver = reset($parts);
+
+        if ($requiredapiver > 0 || $actualapiver > 1) {
+            if (version_compare($actual, $requiredapiver + 1, '>=')) {
+                return 1;
+            }
+        }
+
+        return 0;
+    }
+
+    /**
+     * Executes the specified module.
+     *
+     * @param  string $modulename
+     * @param  array  $params
+     * @param  string $errorlangstr
+     * @return array [0] is the result body and [1] the exit code.
+     */
+    protected function exec_command(string $modulename, array $params, string $errorlangstr) {
+
+        $cmd = $this->pathtopython . ' -m moodlemlbackend.' . $modulename . ' ';
+        foreach ($params as $param) {
+            $cmd .= escapeshellarg($param) . ' ';
+        }
+
+        if (!PHPUNIT_TEST && CLI_SCRIPT) {
+            debugging($cmd, DEBUG_DEVELOPER);
+        }
+
+        $output = null;
+        $exitcode = null;
+        $result = exec($cmd, $output, $exitcode);
+
+        if (!$result) {
+            throw new \moodle_exception($errorlangstr, 'analytics');
+        }
+
+        return [$result, $exitcode];
+    }
+
+    /**
+     * Formats the errors and info in a single info string.
+     *
+     * @param  \stdClass $resultobj
+     * @return \stdClass
+     */
+    private function format_error_info(\stdClass $resultobj) {
+        if (!empty($resultobj->errors)) {
+            $errors = $resultobj->errors;
+            if (is_array($errors)) {
+                $errors = implode(', ', $errors);
+            }
+        } else if (!empty($resultobj->info)) {
+            // Show info if no errors are returned.
+            $errors = $resultobj->info;
+            if (is_array($errors)) {
+                $errors = implode(', ', $errors);
+            }
+        }
+        $resultobj->info = array(get_string('errorpredictionsprocessor', 'analytics', $errors));
+
+        return $resultobj;
+    }
+
+    /**
+     * Returns the url to the python ML server.
+     *
+     * @param  string|null $path
+     * @return \moodle_url
+     */
+    private function get_server_url(?string $path = null) {
+        $protocol = !empty($this->secure) ? 'https' : 'http';
+        $url = $protocol . '://' . rtrim($this->host, '/');
+        if (!empty($this->port)) {
+            $url .= ':' . $this->port;
+        }
+
+        if ($path) {
+            $url .= '/' . $path;
+        }
+
+        return new \moodle_url($url);
+    }
+
+    /**
+     * Sends a request to the python ML server.
+     *
+     * @param  \moodle_url      $url            The requested url in the python ML server
+     * @param  string           $method         The curl method to use
+     * @param  array            $requestparams  Curl request params
+     * @param  array|null       $options        Curl request options
+     * @return array                            [0] for the response body and [1] for the http code
+     */
+    protected function server_request($url, string $method, array $requestparams, ?array $options = null) {
+
+        if ($method !== 'post' && $method !== 'get' && $method !== 'download_one') {
+            throw new \coding_exception('Incorrect request method provided. Only "get", "post" and "download_one"
+                actions are available.');
+        }
+
+        // Connection is allowed to use 'localhost' and other potentially blocked hosts/ports.
+        $curl = new \curl(['ignoresecurity' => true]);
+
+        $authorization = $this->username . ':' . $this->password;
+        $curl->setHeader('Authorization: Basic ' . base64_encode($authorization));
+
+        $responsebody = $curl->{$method}($url, $requestparams, $options);
+
+        if ($curl->info['http_code'] !== 200) {
+            throw new \moodle_exception('errorserver', 'mlbackend_python', '',
+                $this->server_error_str($curl->info['http_code'], $responsebody));
+        }
+
+        return [$responsebody, $curl->info['http_code']];
+    }
+
+    /**
+     * Adds extra information to results info.
+     *
+     * @param  \stdClass $resultobj
+     * @return \stdClass
+     */
+    protected function add_extra_result_info(\stdClass $resultobj): \stdClass {
+
+        if (!empty($resultobj->dir)) {
+            $dir = $resultobj->dir . DIRECTORY_SEPARATOR . 'tensor';
+            $resultobj->info[] = get_string('tensorboardinfo', 'mlbackend_python', $dir);
+        }
+        return $resultobj;
+    }
+
+    /**
+     * Returns the proper return value for the version checking.
+     *
+     * @param  string $actual   Actual moodlemlbackend version
+     * @param  int    $vercheck Version checking result
+     * @return true|string      Returns true on success, a string detailing the error otherwise
+     */
+    private function version_check_return($actual, $vercheck) {
+
+        if ($vercheck === 0) {
+            return true;
+        }
+
+        if ($actual) {
+            $a = [
+                'installed' => $actual,
+                'required' => self::REQUIRED_PIP_PACKAGE_VERSION,
+            ];
+
+            if ($vercheck < 0) {
+                return get_string('packageinstalledshouldbe', 'mlbackend_python', $a);
+
+            } else if ($vercheck > 0) {
+                return get_string('packageinstalledtoohigh', 'mlbackend_python', $a);
+            }
+        }
+
+        if (!$this->useserver) {
+            $cmd = "{$this->pathtopython} -m moodlemlbackend.version";
+        } else {
+            // We can't not know which is the python bin in the python ML server, the most likely
+            // value is 'python'.
+            $cmd = "python -m moodlemlbackend.version";
+        }
+        return get_string('pythonpackagenotinstalled', 'mlbackend_python', $cmd);
+    }
+
+    /**
+     * Hashes the provided dir as a string.
+     *
+     * @param  string $dir Directory path
+     * @return string Hash
+     */
+    private function hash_dir(string $dir) {
+        return md5($dir);
+    }
+
+    /**
+     * Zips the provided directory.
+     *
+     * @param  string $dir Directory path
+     * @return string The zip filename
+     */
+    private function zip_dir(string $dir) {
+
+        $ziptmpdir = make_request_directory();
+        $ziptmpfile = $ziptmpdir . DIRECTORY_SEPARATOR . 'mlbackend.zip';
+
+        $files = get_directory_list($dir);
+        $zipfiles = [];
+        foreach ($files as $file) {
+            $fullpath = $dir . DIRECTORY_SEPARATOR . $file;
+            // Use the relative path to the file as the path in the zip.
+            $zipfiles[$file] = $fullpath;
+        }
+
+        $zip = new \zip_packer();
+        if (!$zip->archive_to_pathname($zipfiles, $ziptmpfile)) {
+            return false;
+        }
+
+        return $ziptmpfile;
+    }
+
+    /**
+     * Error string for httpcode !== 200
+     *
+     * @param int       $httpstatuscode The HTTP status code
+     * @param string    $responsebody   The body of the response
+     */
+    private function server_error_str(int $httpstatuscode, string $responsebody): string {
+        return 'HTTP status code ' . $httpstatuscode . ': ' . $responsebody;
+    }
+}

lib/mlbackend/python/lang/en/mlbackend_python.php

@@ -0,0 +1,46 @@
+<?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/>.
+
+/**
+ * Strings for component 'mlbackend_python'
+ *
+ * @package   mlbackend_python
+ * @copyright 2017 David Monllao {@link http://www.davidmonllao.com}
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+$string['errornoconfigdata'] = 'The server configuration is not complete.';
+$string['errorserver'] = 'Server error {$a}';
+$string['host'] = 'Host';
+$string['hostdesc'] = 'Host';
+$string['packageinstalledshouldbe'] = 'The moodlemlbackend Python package should be updated. The required version is "{$a->required}" and the installed version is "{$a->installed}".';
+$string['packageinstalledtoohigh'] = 'The moodlemlbackend Python package is not compatible with this version of Moodle. The required version is "{$a->required}" or higher as long as it is API-compatible. The installed version "{$a->installed}" is too high.';
+$string['pluginname'] = 'Python machine learning backend';
+$string['port'] = 'Port';
+$string['portdesc'] = 'Port';
+$string['privacy:metadata'] = 'The Python machine learning backend plugin does not store any personal data.';
+$string['pythonpackagenotinstalled'] = 'The moodlemlbackend Python package is not installed or there is a problem with it. Please execute "{$a}" from command line interface for more info.';
+$string['pythonpathnotdefined'] = 'The path to your executable Python binary has not been defined. Please visit "{$a}" to set it.';
+$string['serversettingsinfo'] = 'If \'Use a server\' is enabled, the server settings will be displayed.';
+$string['username'] = 'Username';
+$string['usernamedesc'] = 'String of characters used as a username to communicate between the Moodle server and the Python server.';
+$string['password'] = 'Password';
+$string['passworddesc'] = 'String of characters used as a password to communicate between the Moodle server and the Python server.';
+$string['secure'] = 'Use HTTPS';
+$string['securedesc'] = 'Whether to use HTTP or HTTPS.';
+$string['useserver'] = 'Use a server';
+$string['useserverdesc'] = 'The machine learning backend Python package is not installed on the web server but on a different server.';
+$string['tensorboardinfo'] = 'Launch TensorBoard from command line by typing tensorboard --logdir=\'{$a}\' in your web server.';

lib/mlbackend/python/settings.php

@@ -0,0 +1,54 @@
+<?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/>.
+
+/**
+ * Administration settings definitions for mlbackend_python.
+ *
+ * @package   mlbackend_python
+ * @copyright 2019 David Monllaó
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+if ($ADMIN->fulltree) {
+
+    $info = $OUTPUT->notification(get_string('serversettingsinfo', 'mlbackend_python'), 'info');
+    $settings->add(new admin_setting_heading('mlbackend_python/serversettingsinfo', '', $info));
+
+    $settings->add(new admin_setting_configcheckbox('mlbackend_python/useserver', get_string('useserver', 'mlbackend_python'),
+                       get_string('useserverdesc', 'mlbackend_python'), 0));
+
+    $settings->add(new admin_setting_configtext('mlbackend_python/host', get_string('host', 'mlbackend_python'),
+                       get_string('host', 'mlbackend_python'), '', PARAM_HOST));
+    $settings->hide_if('mlbackend_python/host', 'mlbackend_python/useserver', 'neq', '1');
+
+    $settings->add(new admin_setting_configtext('mlbackend_python/port', get_string('port', 'mlbackend_python'),
+                       get_string('port', 'mlbackend_python'), '', PARAM_INT));
+    $settings->hide_if('mlbackend_python/port', 'mlbackend_python/useserver', 'neq', '1');
+
+    $settings->add(new admin_setting_configcheckbox('mlbackend_python/secure', get_string('secure', 'mlbackend_python'),
+                       get_string('securedesc', 'mlbackend_python'), 0));
+    $settings->hide_if('mlbackend_python/secure', 'mlbackend_python/useserver', 'neq', '1');
+
+    $settings->add(new admin_setting_configtext('mlbackend_python/username', get_string('username', 'mlbackend_python'),
+                       get_string('usernamedesc', 'mlbackend_python'), 'default', PARAM_ALPHANUMEXT));
+    $settings->hide_if('mlbackend_python/username', 'mlbackend_python/useserver', 'neq', '1');
+
+    $settings->add(new admin_setting_configtext('mlbackend_python/password', get_string('password', 'mlbackend_python'),
+                       get_string('passworddesc', 'mlbackend_python'), '', PARAM_ALPHANUMEXT));
+    $settings->hide_if('mlbackend_python/password', 'mlbackend_python/useserver', 'neq', '1');
+}

lib/mlbackend/python/tests/processor_test.php

@@ -0,0 +1,176 @@
+<?php
+// This file is part of Moodle - https://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/>.
+
+namespace mlbackend_python;
+
+/**
+ * Unit tests for the {@link \mlbackend_python\processor} class.
+ *
+ * @package   mlbackend_python
+ * @category  test
+ * @copyright 2019 David Mudrák <david@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class processor_test extends \advanced_testcase {
+
+    /**
+     * Test implementation of the {@link \mlbackend_python\processor::check_pip_package_version()} method.
+     *
+     * @dataProvider check_pip_package_versions
+     * @param string $actual A sample of the actual package version
+     * @param string $required A sample of the required package version
+     * @param int $result Expected value returned by the tested method
+     */
+    public function test_check_pip_package_version($actual, $required, $result): void {
+        $this->assertSame($result, \mlbackend_python\processor::check_pip_package_version($actual, $required));
+    }
+
+    /**
+     * Check that the {@link \mlbackend_python\processor::check_pip_package_version()} can be called with single argument.
+     */
+    public function test_check_pip_package_version_default(): void {
+
+        $this->assertSame(-1, \mlbackend_python\processor::check_pip_package_version('0.0.1'));
+        $this->assertSame(0, \mlbackend_python\processor::check_pip_package_version(
+            \mlbackend_python\processor::REQUIRED_PIP_PACKAGE_VERSION));
+    }
+
+    /**
+     * Provides data samples for the {@link self::test_check_pip_package_version()}.
+     *
+     * @return array
+     */
+    public function check_pip_package_versions() {
+        return [
+            // Exact match.
+            [
+                '0.0.5',
+                '0.0.5',
+                0,
+            ],
+            [
+                '1.0.0',
+                '1.0.0',
+                0,
+            ],
+            // Actual version higher than required, yet still API compatible.
+            [
+                '1.0.3',
+                '1.0.1',
+                0,
+            ],
+            [
+                '2.1.3',
+                '2.0.0',
+                0,
+            ],
+            [
+                '1.1.5',
+                '1.1',
+                0,
+            ],
+            [
+                '2.0.3',
+                '2',
+                0,
+            ],
+            // Actual version not high enough to meet the requirements.
+            [
+                '0.0.5',
+                '1.0.0',
+                -1,
+            ],
+            [
+                '0.37.0',
+                '1.0.0',
+                -1,
+            ],
+            [
+                '0.0.5',
+                '0.37.0',
+                -1,
+            ],
+            [
+                '2.0.0',
+                '2.0.2',
+                -1,
+            ],
+            [
+                '2.7.0',
+                '3.0',
+                -1,
+            ],
+            [
+                '2.8.9-beta1',
+                '3.0',
+                -1,
+            ],
+            [
+                '1.1.0-rc1',
+                '1.1.0',
+                -1,
+            ],
+            // Actual version too high and no longer API compatible.
+            [
+                '2.0.0',
+                '1.0.0',
+                1,
+            ],
+            [
+                '3.1.5',
+                '2.0',
+                1,
+            ],
+            [
+                '3.0.0',
+                '1.0',
+                1,
+            ],
+            [
+                '2.0.0',
+                '0.0.5',
+                1,
+            ],
+            [
+                '3.0.2',
+                '0.37.0',
+                1,
+            ],
+            // Zero major version requirement is fulfilled with 1.x API (0.x are not considered stable APIs).
+            [
+                '1.0.0',
+                '0.0.5',
+                0,
+            ],
+            [
+                '1.8.6',
+                '0.37.0',
+                0,
+            ],
+            // Empty version is never good enough.
+            [
+                '',
+                '1.0.0',
+                -1,
+            ],
+            [
+                '0.0.0',
+                '0.37.0',
+                -1,
+            ],
+        ];
+    }
+}

lib/mlbackend/python/upgrade.txt

@@ -0,0 +1,7 @@
+This files describes API changes in the mlbackend_python code, the
+information provided here is intended especially for developers.
+
+=== 3.8 ===
+
+* The phi coefficient (Matthews' correlation coefficient) has been replaced by
+  the F1 score as the main accuracy metric.

lib/mlbackend/python/version.php

@@ -0,0 +1,29 @@
+<?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/>.
+
+/**
+ * Version details.
+ *
+ * @package    mlbackend_python
+ * @copyright  2017 David Monllao {@link http://www.davidmonllao.com/}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+$plugin->version   = 2024042200; // The current plugin version (Date: YYYYMMDDXX).
+$plugin->requires  = 2024041600; // Requires this Moodle version.
+$plugin->component = 'mlbackend_python'; // Full name of the plugin (used for diagnostics).