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Posted to dev@tomcat.apache.org by ma...@apache.org on 2021/11/04 10:53:25 UTC

[tomcat] branch 9.0.x updated: Provide a little more control over resource caching

This is an automated email from the ASF dual-hosted git repository.

markt pushed a commit to branch 9.0.x
in repository https://gitbox.apache.org/repos/asf/tomcat.git


The following commit(s) were added to refs/heads/9.0.x by this push:
     new 9cf432c  Provide a little more control over resource caching
9cf432c is described below

commit 9cf432cecde096f10ea19ff78d49b03307f85099
Author: Mark Thomas <ma...@apache.org>
AuthorDate: Thu Nov 4 10:52:06 2021 +0000

    Provide a little more control over resource caching
---
 java/org/apache/catalina/WebResourceRoot.java      | 44 ++++++++++++++++++++++
 .../apache/catalina/startup/ContextRuleSet.java    |  8 ++++
 java/org/apache/catalina/webresources/Cache.java   | 17 +++++++++
 .../catalina/webresources/MyCacheStrategy.java     | 29 ++++++++++++++
 .../apache/catalina/webresources/StandardRoot.java | 11 ++++++
 webapps/docs/changelog.xml                         |  5 +++
 6 files changed, 114 insertions(+)

diff --git a/java/org/apache/catalina/WebResourceRoot.java b/java/org/apache/catalina/WebResourceRoot.java
index 8d8092a..ae37893 100644
--- a/java/org/apache/catalina/WebResourceRoot.java
+++ b/java/org/apache/catalina/WebResourceRoot.java
@@ -431,10 +431,54 @@ public interface WebResourceRoot extends Lifecycle {
      */
     void gc();
 
+    /**
+     * Obtain the current caching strategy.
+     * <p>
+     * The default implementation returns {@code null}. Sub-classes wishing to
+     * utilise a {@link CacheStrategy} should provide an appropriate
+     * implementation.
+     *
+     * @return the current caching strategy or {@code null} if no strategy has
+     *         been configured
+     */
+    default CacheStrategy getCacheStrategy() {
+        return null;
+    }
+
+    /**
+     * Set the current caching strategy.
+     * <p>
+     * The default implementation is a NO-OP. Sub-classes wishing to utilise a
+     * {@link CacheStrategy} should provide an appropriate implementation.
+     *
+     * @param strategy The new strategy to use or {@code null} for no strategy
+     */
+    default void setCacheStrategy(CacheStrategy strategy) {
+        // NO-OP
+    }
+
     enum ResourceSetType {
         PRE,
         RESOURCE_JAR,
         POST,
         CLASSES_JAR
     }
+
+    /**
+     * Provides a mechanism to modify the caching behaviour.
+     */
+    interface CacheStrategy {
+
+        /**
+         * Should the result of looking up the resource at the given path be
+         * excluded from caching?
+         *
+         * @param path  The path to check against the strategy to see if the
+         *              result should be cached
+         *
+         * @return {@code true} if the result should not be cached, otherwise
+         *         {@code false}
+         */
+        boolean noCache(String path);
+    }
 }
diff --git a/java/org/apache/catalina/startup/ContextRuleSet.java b/java/org/apache/catalina/startup/ContextRuleSet.java
index e230d54..4aa081e 100644
--- a/java/org/apache/catalina/startup/ContextRuleSet.java
+++ b/java/org/apache/catalina/startup/ContextRuleSet.java
@@ -168,6 +168,14 @@ public class ContextRuleSet implements RuleSet {
                             "setResources",
                             "org.apache.catalina.WebResourceRoot");
 
+        digester.addObjectCreate(prefix + "Context/Resources/CacheStrategy",
+                                 null, // MUST be specified in the element
+                                 "className");
+        digester.addSetProperties(prefix + "Context/Resources/CacheStrategy");
+        digester.addSetNext(prefix + "Context/Resources/CacheStrategy",
+                            "setCacheStrategy",
+                            "org.apache.catalina.WebResourceRoot$CacheStrategy");
+
         digester.addObjectCreate(prefix + "Context/Resources/PreResources",
                                  null, // MUST be specified in the element
                                  "className");
diff --git a/java/org/apache/catalina/webresources/Cache.java b/java/org/apache/catalina/webresources/Cache.java
index b2ce23c..bf762d4 100644
--- a/java/org/apache/catalina/webresources/Cache.java
+++ b/java/org/apache/catalina/webresources/Cache.java
@@ -24,6 +24,7 @@ import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.atomic.AtomicLong;
 
 import org.apache.catalina.WebResource;
+import org.apache.catalina.WebResourceRoot.CacheStrategy;
 import org.apache.juli.logging.Log;
 import org.apache.juli.logging.LogFactory;
 import org.apache.tomcat.util.res.StringManager;
@@ -45,6 +46,7 @@ public class Cache {
     private long ttl = 5000;
     private long maxSize = 10 * 1024 * 1024;
     private int objectMaxSize = (int) maxSize/OBJECT_MAX_SIZE_FACTOR;
+    private CacheStrategy cacheStrategy;
 
     private AtomicLong lookupCount = new AtomicLong(0);
     private AtomicLong hitCount = new AtomicLong(0);
@@ -62,6 +64,13 @@ public class Cache {
             return root.getResourceInternal(path, useClassLoaderResources);
         }
 
+        CacheStrategy strategy = getCacheStrategy();
+        if (strategy != null) {
+            if (strategy.noCache(path)) {
+                return root.getResourceInternal(path, useClassLoaderResources);
+            }
+        }
+
         lookupCount.incrementAndGet();
 
         CachedResource cacheEntry = resourceCache.get(path);
@@ -261,6 +270,14 @@ public class Cache {
         }
     }
 
+    public CacheStrategy getCacheStrategy() {
+        return cacheStrategy;
+    }
+
+    public void setCacheStrategy(CacheStrategy cacheStrategy) {
+        this.cacheStrategy = cacheStrategy;
+    }
+
     public long getTtl() {
         return ttl;
     }
diff --git a/java/org/apache/catalina/webresources/MyCacheStrategy.java b/java/org/apache/catalina/webresources/MyCacheStrategy.java
new file mode 100644
index 0000000..ac23782
--- /dev/null
+++ b/java/org/apache/catalina/webresources/MyCacheStrategy.java
@@ -0,0 +1,29 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.catalina.webresources;
+
+import org.apache.catalina.WebResourceRoot.CacheStrategy;
+
+public class MyCacheStrategy implements CacheStrategy {
+
+
+    @Override
+    public boolean noCache(String path) {
+        System.out.println(path);
+        return true;
+    }
+}
diff --git a/java/org/apache/catalina/webresources/StandardRoot.java b/java/org/apache/catalina/webresources/StandardRoot.java
index 6238e39..ec28485 100644
--- a/java/org/apache/catalina/webresources/StandardRoot.java
+++ b/java/org/apache/catalina/webresources/StandardRoot.java
@@ -498,6 +498,17 @@ public class StandardRoot extends LifecycleMBeanBase implements WebResourceRoot
         return cachingAllowed;
     }
 
+
+    @Override
+    public CacheStrategy getCacheStrategy() {
+        return cache.getCacheStrategy();
+    }
+
+    @Override
+    public void setCacheStrategy(CacheStrategy strategy) {
+        cache.setCacheStrategy(strategy);
+    }
+
     @Override
     public long getCacheTtl() {
         return cache.getTtl();
diff --git a/webapps/docs/changelog.xml b/webapps/docs/changelog.xml
index 6012049..74cd374 100644
--- a/webapps/docs/changelog.xml
+++ b/webapps/docs/changelog.xml
@@ -116,6 +116,11 @@
         Add Javadoc comment which listeners must be nested whithin
         <code>Server</code> elements only. (michaelo)
       </docs>
+      <add>
+        Add support for custom caching strategies for web application resources.
+        This initial implementation allows control over whether or not a
+        resource is cached. (markt)
+      </add>
     </changelog>
   </subsection>
   <subsection name="Coyote">

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Re: [tomcat] branch 9.0.x updated: Provide a little more control over resource caching

Posted by Mark Thomas <ma...@apache.org>.
On 08/11/2021 13:24, Rémy Maucherat wrote:
> On Mon, Nov 8, 2021 at 1:02 PM Mark Thomas <ma...@apache.org> wrote:
>>
>> On 04/11/2021 11:11, Mark Thomas wrote:
>>> On 04/11/2021 10:53, markt@apache.org wrote:
>>>> This is an automated email from the ASF dual-hosted git repository.
>>>>
>>>> markt pushed a commit to branch 9.0.x
>>>> in repository https://gitbox.apache.org/repos/asf/tomcat.git
>>>>
>>>>
>>>> The following commit(s) were added to refs/heads/9.0.x by this push:
>>>>        new 9cf432c  Provide a little more control over resource caching
>>>> 9cf432c is described below
>>>>
>>>> commit 9cf432cecde096f10ea19ff78d49b03307f85099
>>>> Author: Mark Thomas <ma...@apache.org>
>>>> AuthorDate: Thu Nov 4 10:52:06 2021 +0000
>>>>
>>>>       Provide a little more control over resource caching
>>>
>>> Do we want to back-port this to 8.5.x? Because we can't use default
>>> methods it will break any custom WebResourceRoot implementations.
>>
>> Ping (as the releases are approaching).
> 
> I gave up a backport for that reason previously, so I considered I
> should not be breaking the 8.5 API.

Ack. I was leaning the same way so I won't back-port this.

Mark

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Re: [tomcat] branch 9.0.x updated: Provide a little more control over resource caching

Posted by Rémy Maucherat <re...@apache.org>.
On Mon, Nov 8, 2021 at 1:02 PM Mark Thomas <ma...@apache.org> wrote:
>
> On 04/11/2021 11:11, Mark Thomas wrote:
> > On 04/11/2021 10:53, markt@apache.org wrote:
> >> This is an automated email from the ASF dual-hosted git repository.
> >>
> >> markt pushed a commit to branch 9.0.x
> >> in repository https://gitbox.apache.org/repos/asf/tomcat.git
> >>
> >>
> >> The following commit(s) were added to refs/heads/9.0.x by this push:
> >>       new 9cf432c  Provide a little more control over resource caching
> >> 9cf432c is described below
> >>
> >> commit 9cf432cecde096f10ea19ff78d49b03307f85099
> >> Author: Mark Thomas <ma...@apache.org>
> >> AuthorDate: Thu Nov 4 10:52:06 2021 +0000
> >>
> >>      Provide a little more control over resource caching
> >
> > Do we want to back-port this to 8.5.x? Because we can't use default
> > methods it will break any custom WebResourceRoot implementations.
>
> Ping (as the releases are approaching).

I gave up a backport for that reason previously, so I considered I
should not be breaking the 8.5 API.

Rémy

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Re: [tomcat] branch 9.0.x updated: Provide a little more control over resource caching

Posted by Mark Thomas <ma...@apache.org>.
On 04/11/2021 11:11, Mark Thomas wrote:
> On 04/11/2021 10:53, markt@apache.org wrote:
>> This is an automated email from the ASF dual-hosted git repository.
>>
>> markt pushed a commit to branch 9.0.x
>> in repository https://gitbox.apache.org/repos/asf/tomcat.git
>>
>>
>> The following commit(s) were added to refs/heads/9.0.x by this push:
>>       new 9cf432c  Provide a little more control over resource caching
>> 9cf432c is described below
>>
>> commit 9cf432cecde096f10ea19ff78d49b03307f85099
>> Author: Mark Thomas <ma...@apache.org>
>> AuthorDate: Thu Nov 4 10:52:06 2021 +0000
>>
>>      Provide a little more control over resource caching
> 
> Do we want to back-port this to 8.5.x? Because we can't use default 
> methods it will break any custom WebResourceRoot implementations.

Ping (as the releases are approaching).

Mark

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Re: [tomcat] branch 9.0.x updated: Provide a little more control over resource caching

Posted by Mark Thomas <ma...@apache.org>.
On 04/11/2021 10:53, markt@apache.org wrote:
> This is an automated email from the ASF dual-hosted git repository.
> 
> markt pushed a commit to branch 9.0.x
> in repository https://gitbox.apache.org/repos/asf/tomcat.git
> 
> 
> The following commit(s) were added to refs/heads/9.0.x by this push:
>       new 9cf432c  Provide a little more control over resource caching
> 9cf432c is described below
> 
> commit 9cf432cecde096f10ea19ff78d49b03307f85099
> Author: Mark Thomas <ma...@apache.org>
> AuthorDate: Thu Nov 4 10:52:06 2021 +0000
> 
>      Provide a little more control over resource caching

Do we want to back-port this to 8.5.x? Because we can't use default 
methods it will break any custom WebResourceRoot implementations.

Mark

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