MDL-59995 core_admin: added setting to define Python bin path

admin/settings/server.php

@@ -12,6 +12,8 @@
 $temp->add(new admin_setting_configexecutable('aspellpath', new lang_string('aspellpath', 'admin'), new lang_string('edhelpaspellpath'), ''));
 $temp->add(new admin_setting_configexecutable('pathtodot', new lang_string('pathtodot', 'admin'), new lang_string('pathtodot_help', 'admin'), ''));
 $temp->add(new admin_setting_configexecutable('pathtogs', new lang_string('pathtogs', 'admin'), new lang_string('pathtogs_help', 'admin'), '/usr/bin/gs'));
+$temp->add(new admin_setting_configexecutable('pathtopython', new lang_string('pathtopython', 'admin'),
+    new lang_string('pathtopythondesc', 'admin'), ''));
 $ADMIN->add('server', $temp);
 
 

lang/en/admin.php

@@ -835,6 +835,8 @@
 $string['pathtopsql'] = 'Path to psql';
 $string['pathtopsqldesc'] = 'This is only necessary to enter if you have more than one psql on your system (for example if you have more than one version of postgresql installed)';
 $string['pathtopsqlinvalid'] = 'Invalid path to psql - either wrong path or not executable';
+$string['pathtopython'] = 'Path to Python';
+$string['pathtopythondesc'] = 'Path to your executable Python binary.';
 $string['pcreunicodewarning'] = 'It is strongly recommended to use PCRE PHP extension that is compatible with Unicode characters.';
 $string['perfdebug'] = 'Performance info';
 $string['performance'] = 'Performance';

lib/mlbackend/python/classes/processor.php

@@ -40,15 +40,38 @@ class processor implements  \core_analytics\classifier, \core_analytics\regresso
      */
     const REQUIRED_PIP_PACKAGE_VERSION = '0.0.2';
 
+    /**
+     * The path to the Python bin.
+     *
+     * @var string
+     */
+    protected $pathtopython;
+
+    /**
+     * The constructor.
+     */
+    public function __construct() {
+        global $CFG;
+
+        // Set the python location if there is a value.
+        if (!empty($CFG->pathtopython)) {
+            $this->pathtopython = $CFG->pathtopython;
+        }
+    }
+
     /**
      * Is the plugin ready to be used?.
      *
-     * @return bool
+     * @return bool|string Returns true on success, a string detailing the error otherwise
      */
     public function is_ready() {
+        if (empty($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 = 'python -m moodlemlbackend.version';
+        $cmd = "{$this->pathtopython} -m moodlemlbackend.version";
 
         $output = null;
         $exitcode = null;
@@ -84,7 +107,7 @@ public function train_classification($uniqueid, \stored_file $dataset, $outputdi
         // Obtain the physical route to the file.
         $datasetpath = $this->get_file_path($dataset);
 
-        $cmd = 'python -m moodlemlbackend.training ' .
+        $cmd = "{$this->pathtopython} -m moodlemlbackend.training " .
             escapeshellarg($uniqueid) . ' ' .
             escapeshellarg($outputdir) . ' ' .
             escapeshellarg($datasetpath);
@@ -125,7 +148,7 @@ public function classify($uniqueid, \stored_file $dataset, $outputdir) {
         // Obtain the physical route to the file.
         $datasetpath = $this->get_file_path($dataset);
 
-        $cmd = 'python -m moodlemlbackend.prediction ' .
+        $cmd = "{$this->pathtopython} -m moodlemlbackend.prediction " .
             escapeshellarg($uniqueid) . ' ' .
             escapeshellarg($outputdir) . ' ' .
             escapeshellarg($datasetpath);
@@ -168,7 +191,7 @@ public function evaluate_classification($uniqueid, $maxdeviation, $niterations,
         // Obtain the physical route to the file.
         $datasetpath = $this->get_file_path($dataset);
 
-        $cmd = 'python -m moodlemlbackend.evaluation ' .
+        $cmd = "{$this->pathtopython} -m moodlemlbackend.evaluation " .
             escapeshellarg($uniqueid) . ' ' .
             escapeshellarg($outputdir) . ' ' .
             escapeshellarg($datasetpath) . ' ' .

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

@@ -25,3 +25,4 @@
 $string['packageinstalledshouldbe'] = '"moodlemlbackend" python package should be updated. The required version is "{$a->required}" and the installed version is "{$a->installed}"';
 $string['pluginname'] = 'Python machine learning backend';
 $string['pythonpackagenotinstalled'] = '"moodlemlbackend" python package is not installed or there is a problem with it. Please execute "{$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.';