Don't require secondary index when running daemon in slave mode

Add a dummy index implementation and install it when the daemon is
started in slave mode.

Make the reindex program exit with an error if run on a server that
is configured to run in slave mode.

Disable the query ssh command when in slave mode.

Change-Id: Ia323d7dfc3b8f333857ba310072e41943878c11b

gerrit-pgm/src/main/java/com/google/gerrit/pgm/Reindex.java

@@ -27,6 +27,7 @@ import com.google.gerrit.extensions.registration.DynamicSet;
 import com.google.gerrit.lifecycle.LifecycleManager;
 import com.google.gerrit.lifecycle.LifecycleModule;
 import com.google.gerrit.lucene.LuceneIndexModule;
+import com.google.gerrit.pgm.util.Die;
 import com.google.gerrit.pgm.util.SiteProgram;
 import com.google.gerrit.reviewdb.client.Change;
 import com.google.gerrit.reviewdb.client.Project;
@@ -124,6 +125,7 @@ public class Reindex extends SiteProgram {
   private boolean dryRun;
 
   private Injector dbInjector;
+  private Config cfg;
   private Injector sysInjector;
   private ChangeIndex index;
 
@@ -131,6 +133,9 @@ public class Reindex extends SiteProgram {
   public int run() throws Exception {
     mustHaveValidSite();
     dbInjector = createDbInjector(MULTI_USER);
+    cfg = dbInjector.getInstance(
+        Key.get(Config.class, GerritServerConfig.class));
+    checkNotSlaveMode();
     limitThreads();
     disableLuceneAutomaticCommit();
     if (version == null) {
@@ -160,9 +165,13 @@ public class Reindex extends SiteProgram {
     return result;
   }
 
+  private void checkNotSlaveMode() throws Die {
+    if (cfg.getBoolean("container", "slave", false)) {
+      throw die("Cannot run reindex in slave mode");
+    }
+  }
+
   private void limitThreads() {
-    Config cfg =
-        dbInjector.getInstance(Key.get(Config.class, GerritServerConfig.class));
     boolean usePool = cfg.getBoolean("database", "connectionpool",
         dbInjector.getInstance(DataSourceType.class).usePool());
     int poolLimit = cfg.getInt("database", "poollimit",