add mandatory plugins support in conf

config/elasticsearch.yml

@@ -82,11 +82,11 @@
 #
 # node.rack: rack314
 
-
 # By default, multiple nodes are allowed to start from the same installation location
 # to disable it, set the following:
 # node.max_local_storage_nodes: 1
 
+
 #################################### Index ####################################
 
 # You can set a number of options (such as shard/replica options, mapping
@@ -165,6 +165,13 @@
 # path.plugins: /path/to/plugins
 
 
+#################################### Plugin ###################################
+
+# If a plugin listed here is not installed for current node, the node will not start.
+#
+# plugin.mandatory: mapper-attachments,lang-groovy
+
+
 ################################### Memory ####################################
 
 # ElasticSearch performs poorly when JVM starts swapping: you should ensure that

src/main/java/org/elasticsearch/plugins/PluginsService.java

@@ -74,8 +74,22 @@ public PluginsService(Settings settings, Environment environment) {
         // first, find all the ones that are in the classpath
         Map<String, Plugin> plugins = Maps.newHashMap();
         plugins.putAll(loadPluginsFromClasspath(settings));
+        Set<String> sitePlugins = sitePlugins();
+
+        String[] mandatoryPlugins = settings.getAsArray("plugin.mandatory", null);
+        if (mandatoryPlugins != null) {
+            Set<String> missingPlugins = Sets.newHashSet();
+            for (String mandatoryPlugin : mandatoryPlugins) {
+                if (!plugins.containsKey(mandatoryPlugin) && !sitePlugins.contains(mandatoryPlugin) && !missingPlugins.contains(mandatoryPlugin)) {
+                    missingPlugins.add(mandatoryPlugin);
+                }
+            }
+            if (!missingPlugins.isEmpty()) {
+                throw new ElasticSearchException("Missing mandatory plugins " + missingPlugins);
+            }
+        }
 
-        logger.info("loaded {}, sites {}", plugins.keySet(), sitePlugins());
+        logger.info("loaded {}, sites {}", plugins.keySet(), sitePlugins);
 
         this.plugins = ImmutableMap.copyOf(plugins);