added RestartServlet, which is able to trigger a complete restart of the context

scm-webapp/src/main/java/sonia/scm/ResteasyModule.java

@@ -0,0 +1,20 @@
+package sonia.scm;
+
+import com.google.common.collect.ImmutableMap;
+import com.google.inject.servlet.ServletModule;
+import org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher;
+import org.jboss.resteasy.plugins.server.servlet.ResteasyContextParameters;
+
+import javax.inject.Singleton;
+import java.util.Map;
+
+public class ResteasyModule extends ServletModule {
+
+  @Override
+  protected void configureServlets() {
+    bind(HttpServletDispatcher.class).in(Singleton.class);
+
+    Map<String, String> initParams = ImmutableMap.of(ResteasyContextParameters.RESTEASY_SERVLET_MAPPING_PREFIX, "/api");
+    serve("/api/*").with(HttpServletDispatcher.class, initParams);
+  }
+}

scm-webapp/src/main/java/sonia/scm/ScmContextListener.java

@@ -126,6 +126,7 @@ public class ScmContextListener extends GuiceResteasyBootstrapServletContextList
     ClassOverrides overrides = ClassOverrides.findOverrides(pluginLoader.getUberClassLoader());
     List<Module> moduleList = Lists.newArrayList();
 
+    moduleList.add(new ResteasyModule());
     moduleList.add(new ScmInitializerModule());
     moduleList.add(new ScmEventBusModule());
     moduleList.add(new EagerSingletonModule());

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

@@ -34,22 +34,19 @@ 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;
 
+//~--- JDK imports ------------------------------------------------------------
+
 /**
  *
  * @author Sebastian Sdorra
@@ -65,6 +62,8 @@ public class BootstrapContextFilter extends GuiceFilter
 
   //~--- methods --------------------------------------------------------------
 
+  private final BootstrapContextListener listener = new BootstrapContextListener();
+
   /**
    * Restart the whole webapp context.
    *
@@ -85,29 +84,20 @@ public class BootstrapContextFilter extends GuiceFilter
     }
     else
     {
-
-      logger.warn(
-        "destroy filter pipeline, because of a received restart event");
+      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);
+
+      logger.warn("reinitialize filter pipeline, because of a received restart event");
+      initGuice();
     }
   }
 
-  /**
-   * Method description
-   *
-   *
-   * @param filterConfig
-   *
-   * @throws ServletException
-   */
   @Override
   public void init(FilterConfig filterConfig) throws ServletException
   {
     this.filterConfig = filterConfig;
-    super.init(filterConfig);
+
+    initGuice();
 
     if (SCMContext.getContext().getStage() == Stage.DEVELOPMENT)
     {
@@ -116,6 +106,19 @@ public class BootstrapContextFilter extends GuiceFilter
     }
   }
 
+  public void initGuice() throws ServletException {
+    super.init(filterConfig);
+
+    listener.contextInitialized(new ServletContextEvent(filterConfig.getServletContext()));
+  }
+
+  @Override
+  public void destroy() {
+    super.destroy();
+    listener.contextDestroyed(new ServletContextEvent(filterConfig.getServletContext()));
+    ServletContextCleaner.cleanup(filterConfig.getServletContext());
+  }
+
   //~--- fields ---------------------------------------------------------------
 
   /** Field description */

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

@@ -187,40 +187,12 @@ public class BootstrapContextListener implements ServletContextListener
     return Boolean.getBoolean("sonia.scm.boot.disable-core-plugin-extraction");
   }
 
-  /**
-   * 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);
-    }
-  }
-
   /**
    * Method description
    *
    *
    * @param context
    * @param pluginDirectory
-   * @param name
    * @param entry
    *
    * @throws IOException

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

@@ -0,0 +1,97 @@
+package sonia.scm.boot;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import sonia.scm.Priority;
+import sonia.scm.SCMContext;
+import sonia.scm.Stage;
+import sonia.scm.event.ScmEventBus;
+import sonia.scm.filter.WebElement;
+
+import javax.inject.Inject;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+/**
+ * This servlet sends a {@link RestartEvent} to the {@link ScmEventBus} which causes scm-manager to restart the context.
+ * The {@link RestartServlet} can be used for reloading java code or for installing plugins without a complete restart.
+ * At the moment the Servlet accepts only request, if scm-manager was started in the {@link Stage#DEVELOPMENT} stage.
+ *
+ * @since 2.0.0
+ */
+@Priority(0)
+@WebElement("/restart")
+public class RestartServlet extends HttpServlet {
+
+  private static final Logger LOG = LoggerFactory.getLogger(RestartServlet.class);
+
+  private final ObjectMapper objectMapper = new ObjectMapper();
+  private final AtomicBoolean restarting = new AtomicBoolean();
+
+  private final ScmEventBus eventBus;
+  private final Stage stage;
+
+  @Inject
+  public RestartServlet() {
+    this(ScmEventBus.getInstance(), SCMContext.getContext().getStage());
+  }
+
+  RestartServlet(ScmEventBus eventBus, Stage stage) {
+    this.eventBus = eventBus;
+    this.stage = stage;
+  }
+
+  @Override
+  protected void doPost(HttpServletRequest req, HttpServletResponse resp) {
+    LOG.info("received sendRestartEvent request");
+
+    if (isRestartAllowed()) {
+
+      try (InputStream requestInput = req.getInputStream()) {
+        Reason reason = objectMapper.readValue(requestInput, Reason.class);
+        sendRestartEvent(resp, reason);
+      } catch (IOException ex) {
+        LOG.warn("failed to trigger sendRestartEvent event", ex);
+        resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
+      }
+
+    } else {
+      LOG.debug("received restart event in non development stage");
+      resp.setStatus(HttpServletResponse.SC_NOT_ACCEPTABLE);
+    }
+  }
+
+  private boolean isRestartAllowed() {
+    return stage == Stage.DEVELOPMENT;
+  }
+
+  private void sendRestartEvent(HttpServletResponse response, Reason reason) {
+    if ( restarting.compareAndSet(false, true) ) {
+      LOG.info("trigger sendRestartEvent, because of {}", reason.getMessage());
+      eventBus.post(new RestartEvent(RestartServlet.class, reason.getMessage()));
+
+      response.setStatus(HttpServletResponse.SC_ACCEPTED);
+    } else {
+      LOG.warn("scm-manager restarts already");
+      response.setStatus(HttpServletResponse.SC_CONFLICT);
+    }
+  }
+
+  public static class Reason {
+
+    private String message;
+
+    public void setMessage(String message) {
+      this.message = message;
+    }
+
+    public String getMessage() {
+      return message;
+    }
+  }
+}

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

@@ -0,0 +1,59 @@
+package sonia.scm.boot;
+
+import com.google.common.collect.ImmutableSet;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import javax.servlet.ServletContext;
+import java.util.Enumeration;
+import java.util.Set;
+
+/**
+ * Remove cached resources from {@link ServletContext} to allow a clean restart of scm-manager without stale or
+ * duplicated data.
+ *
+ * @since 2.0.0
+ */
+final class ServletContextCleaner {
+
+  private static final Logger LOG = LoggerFactory.getLogger(ServletContextCleaner.class);
+
+  private static final Set<String> REMOVE_PREFIX = ImmutableSet.of(
+    "org.jboss.resteasy",
+    "resteasy",
+    "org.apache.shiro",
+    "sonia.scm"
+  );
+
+  private ServletContextCleaner() {
+  }
+
+  /**
+   * Remove cached attributes from {@link ServletContext}.
+   *
+   * @param servletContext servlet context
+   */
+  static void cleanup(ServletContext servletContext) {
+    LOG.info("remove cached attributes from context");
+
+    Enumeration<String> attributeNames = servletContext.getAttributeNames();
+    while( attributeNames.hasMoreElements()) {
+      String name = attributeNames.nextElement();
+      if (shouldRemove(name)) {
+        LOG.info("remove attribute {} from servlet context", name);
+        servletContext.removeAttribute(name);
+      } else {
+        LOG.info("keep attribute {} in servlet context", name);
+      }
+    }
+  }
+
+  private static boolean shouldRemove(String name) {
+    for (String prefix : REMOVE_PREFIX) {
+      if (name.startsWith(prefix)) {
+        return true;
+      }
+    }
+    return false;
+  }
+}

scm-webapp/src/main/resources/logback.default.xml

@@ -66,9 +66,6 @@
   <logger name="sonia.scm.plugin.ext.DefaultAnnotationScanner" level="INFO" />
   <logger name="sonia.scm.security.ConfigurableLoginAttemptHandler" level="DEBUG" />
 
-  <!-- event bus -->
-  <logger name="sonia.scm.event.LegmanScmEventBus" level="INFO" />
-
   <!-- cgi -->
   <logger name="sonia.scm.web.cgi.DefaultCGIExecutor" level="DEBUG" />
   
@@ -93,7 +90,9 @@
   <logger name="net.sf.ehcache" level="DEBUG" />
   -->
   
-  <logger name="org.jboss.resteasy" level="DEBUG" />
+  <logger name="org.jboss.resteasy" level="INFO" />
+
+  <logger name="sonia.scm.boot.RestartServlet" level="TRACE" />
 
   <root level="WARN">
     <appender-ref ref="STDOUT" />

scm-webapp/src/main/webapp/WEB-INF/web.xml

@@ -41,10 +41,6 @@
 
   <!-- bootstraping -->
 
-  <listener>
-    <listener-class>sonia.scm.boot.BootstrapContextListener</listener-class>
-  </listener>
-
   <filter>
     <filter-name>BootstrapFilter</filter-name>
     <filter-class>sonia.scm.boot.BootstrapContextFilter</filter-class>
@@ -55,25 +51,6 @@
     <url-pattern>/*</url-pattern>
   </filter-mapping>
   
-  <!-- rest -->
-  
-  <context-param>
-    <param-name>resteasy.servlet.mapping.prefix</param-name>
-    <param-value>/api</param-value>
-  </context-param>
-
-  <servlet>
-    <servlet-name>Resteasy</servlet-name>
-    <servlet-class>
-      org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher
-    </servlet-class>
-  </servlet>
-
-  <servlet-mapping>
-    <servlet-name>Resteasy</servlet-name>
-    <url-pattern>/api/*</url-pattern>
-  </servlet-mapping>
-  
   <!-- capture sessions -->
   <!-- 
   TODO remove, we need no longer a session

scm-webapp/src/test/java/sonia/scm/boot/RestartServletTest.java

@@ -0,0 +1,133 @@
+package sonia.scm.boot;
+
+import com.github.legman.Subscribe;
+import com.google.common.base.Charsets;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnitRunner;
+import sonia.scm.Stage;
+import sonia.scm.event.ScmEventBus;
+import sonia.scm.event.ScmTestEventBus;
+
+import javax.servlet.ServletInputStream;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+@RunWith(MockitoJUnitRunner.class)
+public class RestartServletTest {
+
+  @Mock
+  private HttpServletRequest request;
+
+  @Mock
+  private HttpServletResponse response;
+
+  private RestartServlet restartServlet;
+
+  private EventListener listener;
+
+  private void setUpObjectUnderTest(Stage stage) {
+    listener = new EventListener();
+    ScmEventBus eventBus = ScmTestEventBus.getInstance();
+    eventBus.register(listener);
+
+    restartServlet = new RestartServlet(eventBus, stage);
+  }
+
+  @Test
+  public void testRestart() throws IOException {
+    setUpObjectUnderTest(Stage.DEVELOPMENT);
+    setRequestInputReason("something changed");
+
+    restartServlet.doPost(request, response);
+
+    verify(response).setStatus(HttpServletResponse.SC_ACCEPTED);
+
+    RestartEvent restartEvent = listener.restartEvent;
+    assertThat(restartEvent).isNotNull();
+    assertThat(restartEvent.getCause()).isEqualTo(RestartServlet.class);
+    assertThat(restartEvent.getReason()).isEqualTo("something changed");
+  }
+
+  @Test
+  public void testRestartCalledTwice() throws IOException {
+    setUpObjectUnderTest(Stage.DEVELOPMENT);
+
+    setRequestInputReason("initial change");
+    restartServlet.doPost(request, response);
+    verify(response).setStatus(HttpServletResponse.SC_ACCEPTED);
+
+    setRequestInputReason("changed again");
+    restartServlet.doPost(request, response);
+    verify(response).setStatus(HttpServletResponse.SC_CONFLICT);
+  }
+
+  @Test
+  public void testRestartWithInvalidContent() throws IOException {
+    setUpObjectUnderTest(Stage.DEVELOPMENT);
+
+    setRequestInputContent("invalid json");
+
+    restartServlet.doPost(request, response);
+
+    verify(response).setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
+  }
+
+  @Test
+  public void testRestartInProductionStage() throws IOException {
+    setUpObjectUnderTest(Stage.PRODUCTION);
+
+    setRequestInputReason("initial change");
+
+    restartServlet.doPost(request, response);
+
+    verify(response).setStatus(HttpServletResponse.SC_NOT_ACCEPTABLE);
+  }
+
+  private void setRequestInputReason(String message) throws IOException {
+    String content = createReason(message);
+    setRequestInputContent(content);
+  }
+
+  private void setRequestInputContent(String content) throws IOException {
+    InputStream input = createReasonAsInputStream(content);
+    when(request.getInputStream()).thenReturn(createServletInputStream(input));
+  }
+
+  private ServletInputStream createServletInputStream(final InputStream inputStream) {
+    return new ServletInputStream() {
+      @Override
+      public int read() throws IOException {
+        return inputStream.read();
+      }
+    };
+  }
+
+  private InputStream createReasonAsInputStream(String content) {
+    return new ByteArrayInputStream(content.getBytes(Charsets.UTF_8));
+  }
+
+  private String createReason(String message) {
+    return String.format("{\"message\": \"%s\"}", message);
+  }
+
+  public static class EventListener {
+
+    private RestartEvent restartEvent;
+
+    @Subscribe(async = false)
+    public void store(RestartEvent restartEvent) {
+      this.restartEvent = restartEvent;
+    }
+
+  }
+}

scm-webapp/src/test/java/sonia/scm/boot/ServletContextCleanerTest.java

@@ -0,0 +1,53 @@
+package sonia.scm.boot;
+
+import com.google.common.collect.ImmutableSet;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnitRunner;
+
+import javax.servlet.ServletContext;
+
+import java.util.Collection;
+import java.util.Enumeration;
+import java.util.Set;
+import java.util.Vector;
+
+import static org.junit.Assert.*;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+@RunWith(MockitoJUnitRunner.class)
+public class ServletContextCleanerTest {
+
+  @Mock
+  private ServletContext servletContext;
+
+  @Test
+  public void testCleanup() {
+    Set<String> names = ImmutableSet.of(
+      "org.jboss.resteasy.Dispatcher",
+      "resteasy.Deployment",
+      "sonia.scm.Context",
+      "org.eclipse.jetty.HttpServer",
+      "javax.servlet.Context",
+      "org.apache.shiro.SecurityManager"
+    );
+
+    when(servletContext.getAttributeNames()).thenReturn(toEnumeration(names));
+
+    ServletContextCleaner.cleanup(servletContext);
+
+    verify(servletContext).removeAttribute("org.jboss.resteasy.Dispatcher");
+    verify(servletContext).removeAttribute("resteasy.Deployment");
+    verify(servletContext).removeAttribute("sonia.scm.Context");
+    verify(servletContext, never()).removeAttribute("org.eclipse.jetty.HttpServer");
+    verify(servletContext, never()).removeAttribute("javax.servlet.Context");
+    verify(servletContext).removeAttribute("org.apache.shiro.SecurityManager");
+  }
+
+  private <T> Enumeration<T> toEnumeration(Collection<T> collection) {
+    return new Vector<>(collection).elements();
+  }
+}