Issue #5032 - More work towards wrapper based extensible ServletContext

Signed-off-by: Joakim Erdfelt <joakim.erdfelt@gmail.com>

jetty-metrics/pom.xml

@@ -0,0 +1,62 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <parent>
+    <artifactId>jetty-project</artifactId>
+    <groupId>org.eclipse.jetty</groupId>
+    <version>9.4.32-SNAPSHOT</version>
+  </parent>
+  <modelVersion>4.0.0</modelVersion>
+  <artifactId>jetty-metrics</artifactId>
+  <name>Jetty :: Metrics</name>
+  <description>Jetty Metrics</description>
+  <url>http://www.eclipse.org/jetty</url>
+  <properties>
+    <bundle-symbolic-name>${project.groupId}.metrics</bundle-symbolic-name>
+  </properties>
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-jar-plugin</artifactId>
+        <executions>
+          <execution>
+            <id>tests</id>
+            <goals>
+              <goal>test-jar</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>findbugs-maven-plugin</artifactId>
+        <configuration>
+          <onlyAnalyze>org.eclipse.jetty.metrics.*</onlyAnalyze>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
+  <dependencies>
+    <dependency>
+      <groupId>org.eclipse.jetty</groupId>
+      <artifactId>jetty-servlet</artifactId>
+      <version>${project.version}</version>
+    </dependency>
+    <dependency>
+      <groupId>org.eclipse.jetty</groupId>
+      <artifactId>jetty-webapp</artifactId>
+      <version>${project.version}</version>
+    </dependency>
+    <dependency>
+      <groupId>org.eclipse.jetty.toolchain</groupId>
+      <artifactId>jetty-test-helper</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.eclipse.jetty</groupId>
+      <artifactId>jetty-client</artifactId>
+      <version>${project.version}</version>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+</project>

jetty-metrics/src/main/java/org/eclipse/jetty/metrics/MetricsFilterWrapper.java

@@ -0,0 +1,90 @@
+//
+//  ========================================================================
+//  Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
+//  ------------------------------------------------------------------------
+//  All rights reserved. This program and the accompanying materials
+//  are made available under the terms of the Eclipse Public License v1.0
+//  and Apache License v2.0 which accompanies this distribution.
+//
+//      The Eclipse Public License is available at
+//      http://www.eclipse.org/legal/epl-v10.html
+//
+//      The Apache License v2.0 is available at
+//      http://www.opensource.org/licenses/apache2.0.php
+//
+//  You may elect to redistribute this code under either of these licenses.
+//  ========================================================================
+//
+
+package org.eclipse.jetty.metrics;
+
+import java.io.IOException;
+import java.time.Duration;
+import java.time.temporal.ChronoUnit;
+import javax.servlet.Filter;
+import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
+import javax.servlet.ServletContext;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+
+import org.eclipse.jetty.servlet.FilterHolder;
+
+public class MetricsFilterWrapper extends FilterHolder.WrapperFilter
+{
+    private final ServletMetricsListener metricsListener;
+
+    public MetricsFilterWrapper(Filter filter, ServletMetricsListener metricsListener)
+    {
+        super(filter);
+        this.metricsListener = metricsListener;
+    }
+
+    @Override
+    public void init(FilterConfig filterConfig) throws ServletException
+    {
+        ServletContext servletContext = filterConfig.getServletContext();
+        Filter delegate = getWrappedFilter();
+        long start = System.nanoTime();
+        try
+        {
+            metricsListener.onFilterStarting(servletContext, delegate);
+            this.getWrappedFilter().init(filterConfig);
+        }
+        finally
+        {
+            long end = System.nanoTime();
+            long dur = end - start;
+            metricsListener.onFilterReady(servletContext, delegate, Duration.of(dur, ChronoUnit.NANOS));
+        }
+    }
+
+    @Override
+    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException
+    {
+        ServletContext servletContext = request.getServletContext();
+        Filter delegate = getWrappedFilter();
+        long start = System.nanoTime();
+        try
+        {
+            metricsListener.onFilterEnter(servletContext, delegate, request);
+            delegate.doFilter(request, response, chain);
+            long end = System.nanoTime();
+            long dur = end - start;
+            metricsListener.onFilterExit(servletContext, delegate, request, Duration.of(dur, ChronoUnit.NANOS), null);
+        }
+        catch (Throwable cause)
+        {
+            long end = System.nanoTime();
+            long dur = end - start;
+            metricsListener.onFilterExit(servletContext, delegate, request, Duration.of(dur, ChronoUnit.NANOS), cause);
+            throw cause;
+        }
+    }
+
+    @Override
+    public void destroy()
+    {
+    }
+}

jetty-metrics/src/main/java/org/eclipse/jetty/metrics/MetricsHandler.java

@@ -0,0 +1,91 @@
+//
+//  ========================================================================
+//  Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
+//  ------------------------------------------------------------------------
+//  All rights reserved. This program and the accompanying materials
+//  are made available under the terms of the Eclipse Public License v1.0
+//  and Apache License v2.0 which accompanies this distribution.
+//
+//      The Eclipse Public License is available at
+//      http://www.eclipse.org/legal/epl-v10.html
+//
+//      The Apache License v2.0 is available at
+//      http://www.opensource.org/licenses/apache2.0.php
+//
+//  You may elect to redistribute this code under either of these licenses.
+//  ========================================================================
+//
+
+package org.eclipse.jetty.metrics;
+
+import java.util.EventListener;
+import javax.servlet.Filter;
+import javax.servlet.Servlet;
+
+import org.eclipse.jetty.server.HttpChannel;
+import org.eclipse.jetty.servlet.FilterHolder;
+import org.eclipse.jetty.servlet.ListenerHolder;
+import org.eclipse.jetty.servlet.ServletHolder;
+import org.eclipse.jetty.util.component.ContainerLifeCycle;
+import org.eclipse.jetty.util.log.Log;
+import org.eclipse.jetty.util.log.Logger;
+
+public class MetricsHandler extends ContainerLifeCycle
+    implements ServletHolder.WrapperFunction,
+    FilterHolder.WrapperFunction,
+    ListenerHolder.WrapperFunction,
+    HttpChannel.Listener
+{
+    private static final Logger LOG = Log.getLogger(MetricsHandler.class);
+    private final ServletMetricsListener metricsListener;
+
+    public MetricsHandler(ServletMetricsListener metricsListener)
+    {
+        this.metricsListener = metricsListener;
+    }
+
+    @Override
+    public EventListener wrapEventListener(EventListener listener)
+    {
+        LOG.info("wrapEventListener({})", listener);
+        return listener;
+    }
+
+    @Override
+    public Filter wrapFilter(Filter filter)
+    {
+        LOG.info("wrapFilter({})", filter);
+        Filter unwrapped = filter;
+        while (unwrapped instanceof FilterHolder.WrapperFilter)
+        {
+            if (unwrapped instanceof MetricsFilterWrapper)
+            {
+                // Are we already wrapped somewhere along the line?
+                return unwrapped;
+            }
+            // Unwrap
+            unwrapped = ((FilterHolder.WrapperFilter)unwrapped).getWrappedFilter();
+        }
+
+        return new MetricsFilterWrapper(filter, metricsListener);
+    }
+
+    @Override
+    public Servlet wrapServlet(Servlet servlet)
+    {
+        LOG.info("wrapServlet({})", servlet);
+        Servlet unwrapped = servlet;
+        while (unwrapped instanceof ServletHolder.WrapperServlet)
+        {
+            if (unwrapped instanceof MetricsServletWrapper)
+            {
+                // Are we already wrapped somewhere along the line?
+                return unwrapped;
+            }
+            // Unwrap
+            unwrapped = ((ServletHolder.WrapperServlet)unwrapped).getWrappedServlet();
+        }
+
+        return new MetricsServletWrapper(servlet, metricsListener);
+    }
+}

jetty-metrics/src/main/java/org/eclipse/jetty/metrics/MetricsServletWrapper.java

@@ -0,0 +1,91 @@
+//
+//  ========================================================================
+//  Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
+//  ------------------------------------------------------------------------
+//  All rights reserved. This program and the accompanying materials
+//  are made available under the terms of the Eclipse Public License v1.0
+//  and Apache License v2.0 which accompanies this distribution.
+//
+//      The Eclipse Public License is available at
+//      http://www.eclipse.org/legal/epl-v10.html
+//
+//      The Apache License v2.0 is available at
+//      http://www.opensource.org/licenses/apache2.0.php
+//
+//  You may elect to redistribute this code under either of these licenses.
+//  ========================================================================
+//
+
+package org.eclipse.jetty.metrics;
+
+import java.io.IOException;
+import java.time.Duration;
+import java.time.temporal.ChronoUnit;
+import java.util.Objects;
+import javax.servlet.Servlet;
+import javax.servlet.ServletConfig;
+import javax.servlet.ServletContext;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+
+import org.eclipse.jetty.servlet.ServletHolder;
+
+public class MetricsServletWrapper extends ServletHolder.WrapperServlet
+{
+    private final ServletMetricsListener metricsListener;
+
+    public MetricsServletWrapper(Servlet servlet, ServletMetricsListener metricsListener)
+    {
+        super(servlet);
+        this.metricsListener = metricsListener;
+    }
+
+    /**
+     * Entry point for {@link ServletHolder#initialize()}
+     */
+    @Override
+    public void init(ServletConfig config) throws ServletException
+    {
+        ServletContext servletContext = config.getServletContext();
+        Servlet delegate = getWrappedServlet();
+        long start = System.nanoTime();
+        try
+        {
+            metricsListener.onServletStarting(servletContext, delegate);
+            delegate.init(config);
+        }
+        finally
+        {
+            long end = System.nanoTime();
+            long dur = end - start;
+            metricsListener.onServletReady(servletContext, delegate, Duration.of(dur, ChronoUnit.NANOS));
+        }
+    }
+
+    /**
+     * Entry point for all Servlet requests
+     */
+    @Override
+    public void service(ServletRequest req, ServletResponse res) throws ServletException, IOException
+    {
+        ServletContext servletContext = req.getServletContext();
+        Servlet delegate = Objects.requireNonNull(getWrappedServlet());
+        long start = System.nanoTime();
+        try
+        {
+            metricsListener.onServletEnter(servletContext, delegate, req);
+            delegate.service(req, res);
+            long end = System.nanoTime();
+            long dur = end - start;
+            metricsListener.onServletExit(servletContext, delegate, req, Duration.of(dur, ChronoUnit.NANOS), null);
+        }
+        catch (Throwable cause)
+        {
+            long end = System.nanoTime();
+            long dur = end - start;
+            metricsListener.onServletExit(servletContext, delegate, req, Duration.of(dur, ChronoUnit.NANOS), cause);
+            throw cause;
+        }
+    }
+}

jetty-metrics/src/main/java/org/eclipse/jetty/metrics/MetricsWrapper.java

@@ -0,0 +1,23 @@
+//
+//  ========================================================================
+//  Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
+//  ------------------------------------------------------------------------
+//  All rights reserved. This program and the accompanying materials
+//  are made available under the terms of the Eclipse Public License v1.0
+//  and Apache License v2.0 which accompanies this distribution.
+//
+//      The Eclipse Public License is available at
+//      http://www.eclipse.org/legal/epl-v10.html
+//
+//      The Apache License v2.0 is available at
+//      http://www.opensource.org/licenses/apache2.0.php
+//
+//  You may elect to redistribute this code under either of these licenses.
+//  ========================================================================
+//
+
+package org.eclipse.jetty.metrics;
+
+public interface MetricsWrapper
+{
+}