Support wildcard aliases for Drush 8 (#4109)

examples/example.aliases.drushrc.php

@@ -178,6 +178,36 @@
  * to ignore the site at the cwd and just see default drush status:
  *
  *   $ drush @none status
+ *
+ * Wildcard Aliases for Service Providers
+ *
+ * Some service providers that manage Drupal sites allow customers to create
+ * multiple "environments" for a site. It is common for these providers to
+ * also have a feature to automatically create Drush aliases for all of a
+ * user's sites. Rather than write one record for every environment in that
+ * site, it is also possible to write a single "wildcard" alias that represents
+ * all possible environments. This is possible if the contents of each
+ * environment alias are identical save for the name of the environment in
+ * one or more values. The variable `${env-name}` will be substituted with the
+ * environment name wherever it appears.
+ *
+ * Example wildcard record:
+ *
+ * @code
+ *   $aliases['remote-example.*'] = array(
+ *     'remote-host' => '${env-name}.server.domain.com',
+ *     'remote-user' => 'www-admin',
+ *     'root' => '/path/to/${env-name}',
+ *     'uri' => '${env-name}.example.com',
+ *   );
+ * @endcode
+ *
+ * With a wildcard record, any environment name may be used, and will always
+ * match. This is not desirable in instances where the specified environment
+ * does not exist (e.g. if the user made a typo). An alias alter hook in a
+ * policy file may be used to catch these mistakes and report an error.
+ * @see policy.drush.inc for an example on how to do this.
+
  *
  * See `drush help site-alias` for more options for displaying site
  * aliases.  See `drush topic docs-bastion` for instructions on configuring

examples/policy.drush.inc

@@ -66,6 +66,22 @@ function policy_drush_sitealias_alter(&$alias_record) {
     }
     unset($alias_record['parent']);
   }
+
+  // If the alias is a remote wildcard alias, then test to see if the
+  // environment exists, and raise an "environment not found" error if
+  // it does not.
+  if (isset($alias_record['remote-host'])) {
+    $host = $alias_record['remote-host'];
+    if (preg_match('#\.myserver.com$#', $host)) {
+      $ip = gethostbyname($host);
+      // If the return value of gethostbyname equals its input parameter,
+      // that indicates failure.
+      if ($host == $ip) {
+        $aliasName = $alias_record['#name'];
+        return drush_set_error('NO_SUCH_ALIAS', "The alias $aliasName refers to a multidev environment that does not exist.");
+      }
+    }
+  }
 }
 
 /**

includes/sitealias.inc

@@ -722,6 +722,9 @@ function _drush_sitealias_find_and_load_alias_from_file($aliasname, $alias_files
           $aliases[$group_name] = array('site-list' => implode(',', $alias_names), '#group' => $group_name, '#name' => $group_name);
         }
       }
+      // Wildcard check if necessary. This will insert a resolved alias
+      // record into the aliases list, allowing the existing code to match it.
+      _drush_sitealias_wildcard_check($aliasname, $aliases);
       // Store only the named alias into the alias cache
       if ((isset($aliases)) && !empty($aliasname) && array_key_exists($aliasname, $aliases)) {
         drush_set_config_special_contexts($options); // maybe unnecessary
@@ -752,6 +755,49 @@ function _drush_sitealias_find_and_load_alias_from_file($aliasname, $alias_files
   return $result;
 }
 
+/**
+ * Convert a matching wildcard record into the requested record if needed.
+ */
+function _drush_sitealias_wildcard_check($aliasname, &$aliases) {
+  // Don't overwrite a specific alias record with a resolved wildcard record.
+  if (array_key_exists($aliasname, $aliases) || empty($aliasname)) {
+    return;
+  }
+  // If the alias is 'site.dev', then $alias_env is 'dev'
+  $alias_env = preg_replace('#^.*\.#', '', $aliasname);
+  // Check to see if there is a wildcard record.
+  // e.g. if alias is 'site.dev', then look for a record 'site.*'.
+  $wildcard_alias_name = preg_replace('#\.[^.]*$#', '.*', $aliasname);
+  if (($wildcard_alias_name == $aliasname) || empty($alias_env) || !array_key_exists($wildcard_alias_name, $aliases)) {
+    return;
+  }
+
+  $aliases[$aliasname] = _drush_sitealias_replace_wildcard_values($aliases[$wildcard_alias_name], $alias_env);
+  $aliases[$aliasname]['#name'] = $aliasname;
+}
+
+/**
+ * Make substitutions in a wildcard alias record.
+ */
+function _drush_sitealias_replace_wildcard_values($alias_record, $alias_env) {
+  $result = array();
+
+  foreach ($alias_record as $key => $value) {
+    if (is_array($value)) {
+      $result[$key] = _drush_sitealias_replace_wildcard_values($value, $alias_env);
+    }
+    elseif (is_string($value)) {
+      // This substitution looks just like a consolidation/config variable,
+      // although this is the only one we support.
+      $result[$key] = str_replace('${env-name}', $alias_env, $value);
+    }
+    else {
+      $result[$key] = $value;
+    }
+  }
+  return $result;
+}
+
 /**
  * Merges two site aliases.
  *

tests/siteAliasTest.php

@@ -171,6 +171,38 @@ public function testBadAlias() {
     $this->drush('sa', array('@badalias'), array(), NULL, NULL, self::EXIT_ERROR);
   }
 
+  /**
+   * Test wildcard aliases
+   */
+  public function testWildcardAliases() {
+    $aliasPath = UNISH_SANDBOX . '/site-alias-directory';
+    file_exists($aliasPath) ?: mkdir($aliasPath);
+    $aliasFile = $aliasPath . '/wild.aliases.drushrc.php';
+    $aliasContents = <<<EOD
+  <?php
+  // Written by Unish. This file is safe to delete.
+  \$aliases['foo.*'] = array(
+    'remote-host' => '\${env-name}.remote-host.com',
+    'remote-user' => 'www-admin',
+    'root' => '/path/to/\${env-name}',
+    'uri' => 'https://\${env-name}.foo.example.com',
+  );
+EOD;
+    file_put_contents($aliasFile, $aliasContents);
+    $options = array(
+      'alias-path' => $aliasPath,
+      'yes' => NULL,
+    );
+    $this->drush('sa', array('@foo.bar'), $options, NULL, NULL, self::EXIT_SUCCESS);
+    $output = $this->getOutput();
+    $this->assertEquals("\$aliases[\"foo.bar\"] = array (
+  'remote-host' => 'bar.remote-host.com',
+  'remote-user' => 'www-admin',
+  'root' => '/path/to/bar',
+  'uri' => 'https://bar.foo.example.com',
+);", $output);
+  }
+
   /**
    * Ensure that a --uri on CLI overrides on provided by site alias during a backend invoke.
    */