Merge "Enable plugins in BATCH mode"

Documentation/dev-plugins.txt

@@ -109,6 +109,24 @@ will be performed by scanning all classes in the plugin JAR for
   Gerrit-HttpModule: tld.example.project.HttpModuleClassName
 ----
 
+=== Batch runtime
+
+Gerrit can be run as a server, serving HTTP or SSH requests, or as an
+offline program. Plugins can contribute Guice modules to this batch
+runtime by binding `Gerrit-BatchModule` to one of their classes.
+The Guice injector is bound to less classes, and some Gerrit features
+will be absent - on purpose.
+
+This feature was originally introduced to support plugins during an
+offline reindexing task.
+
+----
+  Gerrit-BatchModule: tld.example.project.CoreModuleClassName
+----
+
+In this runtime, only the module designated by `Gerrit-BatchModule` is
+enabled, not `Gerrit-SysModule`.
+
 [[plugin_name]]
 === Plugin Name
 
@@ -2840,6 +2858,9 @@ public class MyPluginModule extends AbstractModule {
 }
 ----
 
+Plugin authors should also consider binding their SubmitRule using a `Gerrit-BatchModule`.
+See link:dev-plugins.html[Batch runtime] for more informations.
+
 == SEE ALSO
 
 * link:js-api.html[JavaScript API]

java/com/google/gerrit/pgm/MigrateToNoteDb.java

@@ -34,6 +34,7 @@ import com.google.gerrit.server.index.DummyIndexModule;
 import com.google.gerrit.server.index.change.ChangeSchemaDefinitions;
 import com.google.gerrit.server.notedb.rebuild.GcAllUsers;
 import com.google.gerrit.server.notedb.rebuild.NoteDbMigrator;
+import com.google.gerrit.server.plugins.PluginGuiceEnvironment;
 import com.google.gerrit.server.schema.DataSourceType;
 import com.google.inject.Inject;
 import com.google.inject.Injector;
@@ -118,6 +119,9 @@ public class MigrateToNoteDb extends SiteProgram {
       sysInjector.injectMembers(this);
       sysManager = new LifecycleManager();
       sysManager.add(sysInjector);
+      sysInjector
+          .getInstance(PluginGuiceEnvironment.class)
+          .setDbCfgInjector(dbInjector, dbInjector);
       sysManager.start();
 
       try (NoteDbMigrator migrator =

java/com/google/gerrit/pgm/Reindex.java

@@ -35,6 +35,7 @@ import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.index.IndexModule;
 import com.google.gerrit.server.index.IndexModule.IndexType;
 import com.google.gerrit.server.index.change.ChangeSchemaDefinitions;
+import com.google.gerrit.server.plugins.PluginGuiceEnvironment;
 import com.google.inject.Inject;
 import com.google.inject.Injector;
 import com.google.inject.Key;
@@ -72,6 +73,7 @@ public class Reindex extends SiteProgram {
 
   private Injector dbInjector;
   private Injector sysInjector;
+  private Injector cfgInjector;
   private Config globalConfig;
 
   @Inject private Collection<IndexDefinition<?, ?, ?>> indexDefs;
@@ -80,6 +82,7 @@ public class Reindex extends SiteProgram {
   public int run() throws Exception {
     mustHaveValidSite();
     dbInjector = createDbInjector(MULTI_USER);
+    cfgInjector = dbInjector.createChildInjector();
     globalConfig = dbInjector.getInstance(Key.get(Config.class, GerritServerConfig.class));
     threads = ThreadLimiter.limitThreads(dbInjector, threads);
     overrideConfig();
@@ -88,9 +91,11 @@ public class Reindex extends SiteProgram {
     dbManager.start();
 
     sysInjector = createSysInjector();
+    sysInjector.getInstance(PluginGuiceEnvironment.class).setDbCfgInjector(dbInjector, cfgInjector);
     LifecycleManager sysManager = new LifecycleManager();
     sysManager.add(sysInjector);
     sysManager.start();
+
     sysInjector.injectMembers(this);
     checkIndicesOption();
 

java/com/google/gerrit/pgm/util/BatchProgramModule.java

@@ -65,6 +65,7 @@ import com.google.gerrit.server.patch.DiffExecutorModule;
 import com.google.gerrit.server.patch.PatchListCacheImpl;
 import com.google.gerrit.server.permissions.DefaultPermissionBackendModule;
 import com.google.gerrit.server.permissions.SectionSortCache;
+import com.google.gerrit.server.plugins.PluginModule;
 import com.google.gerrit.server.project.CommentLinkProvider;
 import com.google.gerrit.server.project.CommitResource;
 import com.google.gerrit.server.project.ProjectCacheImpl;
@@ -111,7 +112,16 @@ public class BatchProgramModule extends FactoryModule {
     install(BatchUpdate.module());
     install(PatchListCacheImpl.module());
 
-    // Plugins are not loaded and we're just running through each change
+    // There is the concept of LifecycleModule, in Gerrit's own extension to Guice, which has these:
+    //  listener().to(SomeClassImplementingLifecycleListener.class);
+    // and the start() methods of each such listener are executed in the order they are declared.
+    // Makes sure that PluginLoader.start() is executed before the LuceneIndexModule.start() so that
+    // plugins get loaded and the respective Guice modules installed so that the on-line reindexing
+    // will happen with the proper classes (e.g. group backends, custom Prolog predicates) and the
+    // associated rules ready to be evaluated.
+    install(new PluginModule());
+
+    // We're just running through each change
     // once, so don't worry about cache removal.
     bind(new TypeLiteral<DynamicSet<CacheRemovalListener>>() {})
         .toInstance(DynamicSet.<CacheRemovalListener>emptySet());

java/com/google/gerrit/server/plugins/ServerPlugin.java

@@ -46,6 +46,7 @@ public class ServerPlugin extends Plugin {
   private final String metricsPrefix;
   private final GerritRuntime gerritRuntime;
   protected Class<? extends Module> sysModule;
+  protected Class<? extends Module> batchModule;
   protected Class<? extends Module> sshModule;
   protected Class<? extends Module> httpModule;
 
@@ -91,6 +92,7 @@ public class ServerPlugin extends Plugin {
     String sysName = main.getValue("Gerrit-Module");
     String sshName = main.getValue("Gerrit-SshModule");
     String httpName = main.getValue("Gerrit-HttpModule");
+    String batchName = main.getValue("Gerrit-BatchModule");
 
     if (!Strings.isNullOrEmpty(sshName) && getApiType() != Plugin.ApiType.PLUGIN) {
       throw new InvalidPluginException(
@@ -99,6 +101,7 @@ public class ServerPlugin extends Plugin {
     }
 
     try {
+      this.batchModule = load(batchName, classLoader);
       this.sysModule = load(sysName, classLoader);
       this.sshModule = load(sshName, classLoader);
       this.httpModule = load(httpName, classLoader);
@@ -108,7 +111,7 @@ public class ServerPlugin extends Plugin {
   }
 
   @SuppressWarnings("unchecked")
-  protected static Class<? extends Module> load(String name, ClassLoader pluginLoader)
+  protected static Class<? extends Module> load(@Nullable String name, ClassLoader pluginLoader)
       throws ClassNotFoundException {
     if (Strings.isNullOrEmpty(name)) {
       return null;
@@ -180,6 +183,18 @@ public class ServerPlugin extends Plugin {
     serverManager = new LifecycleManager();
     serverManager.add(root);
 
+    if (gerritRuntime == GerritRuntime.BATCH) {
+      if (batchModule != null) {
+        sysInjector = root.createChildInjector(root.getInstance(batchModule));
+        serverManager.add(sysInjector);
+      } else {
+        sysInjector = root;
+      }
+
+      serverManager.start();
+      return;
+    }
+
     AutoRegisterModules auto = null;
     if (sysModule == null && sshModule == null && httpModule == null) {
       auto = new AutoRegisterModules(getName(), env, scanner, classLoader);