Add multisite support

* Add new parameters for multisite support
* give each multisite its own queue to prevent starvation

includes/utilities.inc

@@ -19,6 +19,26 @@ function islandora_job_get_client() {
   return $client;
 }
 
+/**
+ * Get job function name.
+ *
+ * This function allows support for multisites by adding the site
+ * name to each job function.
+ *
+ * @param string $job_name
+ *   Name of the job without site.
+ *
+ * @return string
+ *   Job name with site added.
+ */
+function islandora_job_function_name($job_name) {
+  // Chop the 'sites/' part of the path off. This gives you the name of the
+  // site dir for the multisite, for example sites/example would be example
+  // we use this to create the queue for this multisite.
+  $site = substr(conf_path(),6);
+  return $site == 'default' ? $job_name : "{$site}_{$job_name}";
+}
+
 /**
  * Constructs a payload from arguments passed to various API functions.
  *
@@ -32,11 +52,15 @@ function islandora_job_get_client() {
  *   A JSON encoded payload for Gearman.
  */
 function islandora_job_format_payload($job_name, $args) {
+  global $user;
+  global $base_url;
   array_shift($args);
   return json_encode(
     array(
       "func" => $job_name,
       "args" => $args,
+      "site" => $base_url,
+      "uid" => $user->uid,
     )
   );
 }

islandora_job.module

@@ -38,7 +38,7 @@ function islandora_job_submit($job_name) {
   module_load_include('inc', 'islandora_job', 'includes/utilities');
   $payload = islandora_job_format_payload($job_name, func_get_args());
   $client = islandora_job_get_client();
-  return $client->doNormal($job_name, $payload);
+  return $client->doNormal(islandora_job_function_name($job_name), $payload);
 }
 
 /**
@@ -58,7 +58,7 @@ function islandora_job_submit_background($job_name) {
   module_load_include('inc', 'islandora_job', 'includes/utilities');
   $payload = islandora_job_format_payload($job_name, func_get_args());
   $client = islandora_job_get_client();
-  return $client->doBackground($job_name, $payload);
+  return $client->doBackground(islandora_job_function_name($job_name), $payload);
 }
 
 /**
@@ -92,7 +92,7 @@ function islandora_job_submit_batch($tasks, $callback = NULL) {
     // Push on a dummy arg as if this array came from func_get_args().
     array_unshift($args, '');
     $payload = islandora_job_format_payload($job_name, $args);
-    $client->addTask($job_name, $payload);
+    $client->addTask(islandora_job_function_name($job_name), $payload);
   }
   return $client->runTasks();
 }