MDL-53535 search_solr: Solr version restrictions

Also removing is_server_ready call from execute_query as in production
workflows search is done through \core_search\manager::search and
\core_search\manager::instance already checks is_server_ready. In
testing environment setUp functions should check that the server is
ready before performing other actions.

search/classes/engine.php

@@ -79,8 +79,6 @@ abstract class engine {
      *
      * Search engine availability should be checked separately.
      *
-     * @see self::is_installed
-     * @see self::is_server_ready
      * @return void
      */
     public function __construct() {

search/classes/manager.php

@@ -109,6 +109,8 @@ public function __construct($engine) {
     /**
      * Returns an initialised \core_search instance.
      *
+     * @see \core_search\engine::is_installed
+     * @see \core_search\engine::is_server_ready
      * @throws \core_search\engine_exception
      * @return \core_search\manager
      */

search/engine/solr/classes/engine.php

@@ -112,11 +112,6 @@ public function execute_query($filters, $usercontexts) {
         // If there is any problem we trigger the exception as soon as possible.
         $client = $this->get_search_client();
 
-        $serverstatus = $this->is_server_ready();
-        if ($serverstatus !== true) {
-            throw new \core_search\engine_exception('engineserverstatus', 'search');
-        }
-
         $query = new \SolrDisMaxQuery();
         $maxrows = \core_search\manager::MAX_RESULTS;
         if ($this->file_indexing_enabled()) {
@@ -948,6 +943,29 @@ public function delete($areaid = null) {
      */
     public function is_server_ready() {
 
+        $configured = $this->is_server_configured();
+        if ($configured !== true) {
+            return $configured;
+        }
+
+        // Check that the schema is already set up.
+        try {
+            $schema = new \search_solr\schema();
+            $schema->validate_setup();
+        } catch (\moodle_exception $e) {
+            return $e->getMessage();
+        }
+
+        return true;
+    }
+
+    /**
+     * Is the solr server properly configured?.
+     *
+     * @return true|string Returns true if all good or an error string.
+     */
+    public function is_server_configured() {
+
         if (empty($this->config->server_hostname) || empty($this->config->indexname)) {
             return 'No solr configuration found';
         }
@@ -957,24 +975,30 @@ public function is_server_ready() {
         }
 
         try {
-            @$client->ping();
+            if ($this->get_solr_major_version() < 4) {
+                // Minimum solr 4.0.
+                return get_string('minimumsolr4', 'search_solr');
+            }
         } catch (\SolrClientException $ex) {
             return 'Solr client error: ' . $ex->getMessage();
         } catch (\SolrServerException $ex) {
             return 'Solr server error: ' . $ex->getMessage();
         }
 
-        // Check that setup schema has already run.
-        try {
-            $schema = new \search_solr\schema();
-            $schema->validate_setup();
-        } catch (\moodle_exception $e) {
-            return $e->getMessage();
-        }
-
         return true;
     }
 
+    /**
+     * Returns the solr server major version.
+     *
+     * @return int
+     */
+    public function get_solr_major_version() {
+        $systemdata = $this->get_search_client()->system();
+        $solrversion = $systemdata->getResponse()->offsetGet('lucene')->offsetGet('solr-spec-version');
+        return intval(substr($solrversion, 0, strpos($solrversion, '.')));
+    }
+
     /**
      * Checks if the PHP Solr extension is available.
      *

search/engine/solr/classes/schema.php

@@ -79,6 +79,28 @@ public function __construct() {
         $this->curl->setHeader('Content-type: application/json');
     }
 
+    /**
+     * Can setup be executed against the configured server.
+     *
+     * @return true|string True or error message.
+     */
+    public function can_setup_server() {
+
+        $engine = new \search_solr\engine();
+        $status = $engine->is_server_configured();
+        if ($status !== true) {
+            return $status;
+        }
+
+        // We know that the server is ready here.
+        if ($engine->get_solr_major_version() < 5) {
+            // Schema setup script only available for 5.0 onwards.
+            return get_string('schemasetupfromsolr5', 'search_solr');
+        }
+
+        return true;
+    }
+
     /**
      * Setup solr stuff required by moodle.
      *

search/engine/solr/lang/en/search_solr.php

@@ -32,11 +32,13 @@
 $string['fileindexsettings'] = 'File indexing settings';
 $string['maxindexfilekb'] = 'Maximum file size to index (kB)';
 $string['maxindexfilekb_help'] = 'Files larger than this number of kilobytes will be skipped for search indexing. 0 to index files of any size.';
+$string['minimumsolr4'] = 'Solr 4.0 is the minimum version required for Moodle';
 $string['missingconfig'] = 'Your Apache Solr server is not yet configured in Moodle.';
 $string['multivaluedfield'] = 'Field "{$a}" returned an array instead of a scalar, the field is probably defined in Solr with "Multivalued" to true, this means that Solr autocreated the field for you when you indexed data because you forgot to run search/engine/solr/cli/setup_schema.php. Please delete the current index, create a new one and run setup_schema.php before indexing data in Solr.';
 $string['nodatafromserver'] = 'No data from server';
 $string['pluginname'] = 'Solr';
 $string['schemafieldautocreated'] = 'Field "{$a}" already exists in Solr schema. You probably forgot to run this script before indexing data and fields were autocreated by Solr. Please delete the current index, create a new one and run setup_schema.php again before indexing data in Solr.';
+$string['schemasetupfromsolr5'] = 'Your Solr server version is lower than 5.0, this script can only set your schema if your Solr version is 5.0 or higher. You need to manually set the fields in your schema according to \\search_solr\\document::get_default_fields_definition()';
 $string['searchinfo'] = 'Search queries';
 $string['searchinfo_help'] = 'Features you can use while performing search queries:
 

search/engine/solr/setup_schema.php

@@ -34,8 +34,24 @@
 require_login(null, false);
 require_capability('moodle/site:config', context_system::instance());
 
+$returnurl = new moodle_url('/admin/settings.php', array('section' => 'manageglobalsearch'));
+
 $schema = new \search_solr\schema();
+
+$status = $schema->can_setup_server();
+if ($status !== true) {
+
+    $PAGE->set_context(context_system::instance());
+    $PAGE->set_url(new moodle_url('/search/engine/solr/setup_schema.php'));
+
+    echo $OUTPUT->header();
+    echo $OUTPUT->notification($status, \core\output\notification::NOTIFY_ERROR);
+    echo $OUTPUT->box($OUTPUT->action_link($returnurl, get_string('continue')), 'generalbox centerpara');
+    echo $OUTPUT->footer();
+
+    exit(1);
+}
+
 $schema->setup();
 
-$url = new moodle_url('/admin/settings.php', array('section' => 'manageglobalsearch'));
-redirect($url, get_string('setupok', 'search_solr'), 4);
+redirect($returnurl, get_string('setupok', 'search_solr'), 4);