Add configuration to allow deferring the initial Deployment until after Server is started

jetty-deploy/pom.xml

@@ -59,5 +59,9 @@
       <artifactId>jetty-test-helper</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.awaitility</groupId>
+      <artifactId>awaitility</artifactId>
+    </dependency>
   </dependencies>
 </project>

jetty-deploy/src/main/config/etc/jetty-deploy.xml

@@ -53,6 +53,7 @@
                   </Default>
                 </Property>
               </Set>
+              <Set name="deferInitialScan"><Property name="jetty.deploy.deferInitialScan" default="false"/></Set>
               <Set name="scanInterval"><Property name="jetty.deploy.scanInterval" default="1"/></Set>
               <Set name="extractWars"><Property name="jetty.deploy.extractWars" default="true"/></Set>
               <Set name="configurationManager">

jetty-deploy/src/main/config/modules/deploy.mod

@@ -20,8 +20,15 @@ etc/jetty-deploy.xml
 # Defaults Descriptor for all deployed webapps
 # jetty.deploy.defaultsDescriptorPath=${jetty.base}/etc/webdefault.xml
 
+# Defer Initial Scan
+# true to have the initial scan deferred until the Server component is started.
+#      Note: deploy failures do not fail server startup in a deferred initial scan mode.
+# false (default) to have initial scan occur as normal.
+# jetty.deploy.deferInitialScan=false
+
 # Monitored directory scan period (seconds)
 # jetty.deploy.scanInterval=1
 
 # Whether to extract *.war files
 # jetty.deploy.extractWars=true
+

jetty-deploy/src/main/java/org/eclipse/jetty/deploy/providers/ScanningAppProvider.java

@@ -27,11 +27,13 @@
 import org.eclipse.jetty.deploy.App;
 import org.eclipse.jetty.deploy.AppProvider;
 import org.eclipse.jetty.deploy.DeploymentManager;
+import org.eclipse.jetty.server.Server;
 import org.eclipse.jetty.util.Scanner;
 import org.eclipse.jetty.util.annotation.ManagedAttribute;
 import org.eclipse.jetty.util.annotation.ManagedObject;
 import org.eclipse.jetty.util.annotation.ManagedOperation;
 import org.eclipse.jetty.util.component.ContainerLifeCycle;
+import org.eclipse.jetty.util.component.LifeCycle;
 import org.eclipse.jetty.util.resource.Resource;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -49,6 +51,7 @@ public abstract class ScanningAppProvider extends ContainerLifeCycle implements
     private int _scanInterval = 10;
     private Scanner _scanner;
     private boolean _useRealPaths;
+    private boolean _deferInitialScan = false;
 
     private final Scanner.DiscreteListener _scannerListener = new Scanner.DiscreteListener()
     {
@@ -152,9 +155,30 @@ protected void doStart() throws Exception
         _scanner.setReportDirs(true);
         _scanner.setScanDepth(1); //consider direct dir children of monitored dir
         _scanner.addListener(_scannerListener);
-
+        _scanner.setReportExistingFilesOnStartup(true);
+        _scanner.setAutoStartScanning(!_deferInitialScan);
         addBean(_scanner);
 
+        if (isDeferInitialScan())
+        {
+            // Setup listener to wait for Server in STARTED state, which
+            // triggers the first scan of the monitored directories
+            getDeploymentManager().getServer().addEventListener(
+                new LifeCycle.Listener()
+                {
+                    @Override
+                    public void lifeCycleStarted(LifeCycle event)
+                    {
+                        if (event instanceof Server)
+                        {
+                            if (LOG.isDebugEnabled())
+                                LOG.debug("Triggering Deferred Scan of {}", _monitored);
+                            _scanner.startScanning();
+                        }
+                    }
+                });
+        }
+
         super.doStart();
     }
 
@@ -296,6 +320,34 @@ public void setMonitoredDirectories(Collection<String> directories)
         }
     }
 
+    /**
+     * Test if initial scan should be deferred.
+     *
+     * @return true if initial scan is deferred, false to have initial scan occur on startup of ScanningAppProvider.
+     */
+    public boolean isDeferInitialScan()
+    {
+        return _deferInitialScan;
+    }
+
+    /**
+     * Flag to control initial scan behavior.
+     *
+     * <ul>
+     *     <li>{@code true} - to have initial scan deferred until the {@link Server} component
+     *     has reached it's STARTED state.<br>
+     *     Note: any failures in a deploy will not fail the Server startup in this mode.</li>
+     *     <li>{@code false} - (default value) to have initial scan occur as normal on
+     *     ScanningAppProvider startup.</li>
+     * </ul>
+     *
+     * @param defer true to defer initial scan, false to have initial scan occur on startup of ScanningAppProvider.
+     */
+    public void setDeferInitialScan(boolean defer)
+    {
+        _deferInitialScan = defer;
+    }
+
     public void setScanInterval(int scanInterval)
     {
         _scanInterval = scanInterval;