Re-run config validation from bin/search

Summary:
Ref T12450. Normally, we validate config when:

  - You restart the webserver.
  - You edit it with `bin/config set ...`.
  - You edit it with the web UI.

However, you can also change config by editing `local.json`, `some_env.conf.php`, a `SiteConfig` class, etc. In these cases, you may miss config warnings.

Explicitly re-run search config checks from `bin/search`, similar to the additional database checks we run from `bin/storage`, to try to produce a better error message if the user has made a configuration error.

Test Plan:
```
$ ./bin/search init
Usage Exception: Setting "cluster.search" is misconfigured: Invalid search engine type: elastic. Valid types are: elasticsearch, mysql.
```

Reviewers: chad, 20after4

Reviewed By: 20after4

Maniphest Tasks: T12450

Differential Revision: https://secure.phabricator.com/D17574

src/applications/search/management/PhabricatorSearchManagementIndexWorkflow.php

@@ -45,6 +45,8 @@ final class PhabricatorSearchManagementIndexWorkflow
   }
 
   public function execute(PhutilArgumentParser $args) {
+    $this->validateClusterSearchConfig();
+
     $console = PhutilConsole::getConsole();
 
     $is_all = $args->getArg('all');

src/applications/search/management/PhabricatorSearchManagementInitWorkflow.php

@@ -11,6 +11,7 @@ final class PhabricatorSearchManagementInitWorkflow
   }
 
   public function execute(PhutilArgumentParser $args) {
+    $this->validateClusterSearchConfig();
 
     $work_done = false;
     foreach (PhabricatorSearchService::getAllServices() as $service) {

src/applications/search/management/PhabricatorSearchManagementWorkflow.php

@@ -1,4 +1,26 @@
 <?php
 
 abstract class PhabricatorSearchManagementWorkflow
-  extends PhabricatorManagementWorkflow {}
+  extends PhabricatorManagementWorkflow {
+
+  protected function validateClusterSearchConfig() {
+    // Configuration is normally validated by setup self-checks on the web
+    // workflow, but users may reasonsably run `bin/search` commands after
+    // making manual edits to "local.json". Re-verify configuration here before
+    // continuing.
+
+    $config_key = 'cluster.search';
+    $config_value = PhabricatorEnv::getEnvConfig($config_key);
+
+    try {
+      PhabricatorClusterSearchConfigOptionType::validateValue($config_value);
+    } catch (Exception $ex) {
+      throw new PhutilArgumentUsageException(
+        pht(
+          'Setting "%s" is misconfigured: %s',
+          $config_key,
+          $ex->getMessage()));
+    }
+  }
+
+}

src/infrastructure/cluster/config/PhabricatorClusterSearchConfigOptionType.php

@@ -4,6 +4,10 @@ final class PhabricatorClusterSearchConfigOptionType
   extends PhabricatorConfigJSONOptionType {
 
   public function validateOption(PhabricatorConfigOption $option, $value) {
+    self::validateClusterSearchConfigValue($value);
+  }
+
+  public static function validateValue($value) {
     if (!is_array($value)) {
       throw new Exception(
         pht(
@@ -46,7 +50,8 @@ final class PhabricatorClusterSearchConfigOptionType
 
       if (!array_key_exists($spec['type'], $engines)) {
         throw new Exception(
-          pht('Invalid search engine type: %s. Valid types include: %s',
+          pht(
+            'Invalid search engine type: %s. Valid types are: %s.',
             $spec['type'],
             implode(', ', array_keys($engines))));
       }