experimental implementation of a context restart, to speed up redeployments durring plugin development

scm-webapp/src/main/java/sonia/scm/boot/BootstrapContextFilter.java

@@ -0,0 +1,123 @@
+/**
+ * Copyright (c) 2014, Sebastian Sdorra All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer. 2. Redistributions in
+ * binary form must reproduce the above copyright notice, this list of
+ * conditions and the following disclaimer in the documentation and/or other
+ * materials provided with the distribution. 3. Neither the name of SCM-Manager;
+ * nor the names of its contributors may be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * http://bitbucket.org/sdorra/scm-manager
+ *
+ */
+
+
+
+package sonia.scm.boot;
+
+//~--- non-JDK imports --------------------------------------------------------
+
+import com.github.legman.Subscribe;
+
+import com.google.inject.servlet.GuiceFilter;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import sonia.scm.SCMContext;
+import sonia.scm.Stage;
+import sonia.scm.event.ScmEventBus;
+
+//~--- JDK imports ------------------------------------------------------------
+
+import javax.servlet.FilterConfig;
+import javax.servlet.ServletContextEvent;
+import javax.servlet.ServletException;
+
+/**
+ *
+ * @author Sebastian Sdorra
+ */
+public class BootstrapContextFilter extends GuiceFilter
+{
+
+  /**
+   * the logger for BootstrapContextFilter
+   */
+  private static final Logger logger =
+    LoggerFactory.getLogger(BootstrapContextFilter.class);
+
+  //~--- methods --------------------------------------------------------------
+
+  /**
+   * Restart the whole webapp context.
+   *
+   *
+   * @param event restart event
+   *
+   * @throws ServletException
+   */
+  @Subscribe(async = false)
+  public void handleRestartEvent(RestartEvent event) throws ServletException
+  {
+    logger.warn("received restart event from {} with reason: {}",
+      event.getCause(), event.getReason());
+
+    if (filterConfig == null)
+    {
+      logger.error("filter config is null, scm-manager is not initialized");
+    }
+    else
+    {
+
+      logger.warn(
+        "destroy filter pipeline, because of a received restart event");
+      destroy();
+      logger.warn(
+        "reinitialize filter pipeline, because of a received restart event");
+      super.init(filterConfig);
+    }
+  }
+
+  /**
+   * Method description
+   *
+   *
+   * @param filterConfig
+   *
+   * @throws ServletException
+   */
+  @Override
+  public void init(FilterConfig filterConfig) throws ServletException
+  {
+    this.filterConfig = filterConfig;
+    super.init(filterConfig);
+
+    if (SCMContext.getContext().getStage() == Stage.DEVELOPMENT)
+    {
+      logger.info("register for restart events");
+      ScmEventBus.getInstance().register(this);
+    }
+  }
+
+  //~--- fields ---------------------------------------------------------------
+
+  /** Field description */
+  private FilterConfig filterConfig;
+}

scm-webapp/src/main/java/sonia/scm/boot/BootstrapContextListener.java

@@ -33,15 +33,20 @@ package sonia.scm.boot;
 
 //~--- non-JDK imports --------------------------------------------------------
 
+import com.github.legman.Subscribe;
+
 import com.google.common.base.Charsets;
 import com.google.common.collect.ImmutableList;
 import com.google.common.io.Files;
+import com.google.inject.servlet.GuiceFilter;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import sonia.scm.SCMContext;
 import sonia.scm.ScmContextListener;
+import sonia.scm.Stage;
+import sonia.scm.event.ScmEventBus;
 import sonia.scm.plugin.Plugin;
 import sonia.scm.plugin.PluginException;
 import sonia.scm.plugin.PluginLoadException;
@@ -128,6 +133,7 @@ public class BootstrapContextListener implements ServletContextListener
       }
     }
 
+    context = null;
     contextListener = null;
   }
 
@@ -140,7 +146,8 @@ public class BootstrapContextListener implements ServletContextListener
   @Override
   public void contextInitialized(ServletContextEvent sce)
   {
-    ServletContext context = sce.getServletContext();
+    context = sce.getServletContext();
+
     PluginIndex index = readCorePluginIndex(context);
 
     File pluginDirectory = getPluginDirectory();
@@ -163,6 +170,42 @@ public class BootstrapContextListener implements ServletContextListener
     }
 
     contextListener.contextInitialized(sce);
+    
+        // register for restart events
+    if (!registered
+      && (SCMContext.getContext().getStage() == Stage.DEVELOPMENT))
+    {
+      logger.info("register for restart events");
+      ScmEventBus.getInstance().register(this);
+      registered = true;
+    }
+  }
+
+  /**
+   * Restart the whole webapp context.
+   *
+   *
+   * @param event restart event
+   */
+  @Subscribe
+  public void handleRestartEvent(RestartEvent event)
+  {
+    logger.warn("received restart event from {} with reason: {}",
+      event.getCause(), event.getReason());
+
+    if (context == null)
+    {
+      logger.error("context is null, scm-manager is not initialized");
+    }
+    else
+    {
+      ServletContextEvent sce = new ServletContextEvent(context);
+
+      logger.warn("destroy context, because of a received restart event");
+      contextDestroyed(sce);
+      logger.warn("reinitialize context, because of a received restart event");
+      contextInitialized(sce);
+    }
   }
 
   /**
@@ -391,6 +434,12 @@ public class BootstrapContextListener implements ServletContextListener
 
   //~--- fields ---------------------------------------------------------------
 
+  /** Field description */
+  private ServletContext context;
+
   /** Field description */
   private ScmContextListener contextListener;
+
+  /** Field description */
+  private boolean registered = false;
 }