AspectJ Weaver Agent

This change adds the AspectJ Weaver Agent which will detect the existing of an
aop.xml and the aspectjweaver JAR and configure runtime weaving if they both
exist.

[resolves #473]

Author: nebhale

README.md

@@ -73,6 +73,7 @@ To learn how to configure various properties of the buildpack, follow the "Confi
   * [Tomcat](docs/container-tomcat.md) ([Configuration](docs/container-tomcat.md#configuration))
 * Standard Frameworks
   * [AppDynamics Agent](docs/framework-app_dynamics_agent.md) ([Configuration](docs/framework-app_dynamics_agent.md#configuration))
+  * [AspectJ Weaver Agent](docs/framework-aspectj_weaver_agent.md) ([Configuration](docs/framework-aspectj_weaver_agent.md#configuration))
   * [Client Certificate Mapper](docs/framework-client_certificate_mapper.md) ([Configuration](docs/framework-client_certificate_mapper.md#configuration))
   * [Container Customizer](docs/framework-container_customizer.md) ([Configuration](docs/framework-container_customizer.md#configuration))
   * [Container Security Provider](docs/framework-container_security_provider.md) ([Configuration](docs/framework-container_security_provider.md#configuration))

config/aspectj_weaver_agent.yml

@@ -0,0 +1,18 @@
+# Cloud Foundry Java Buildpack
+# Copyright 2013-2017 the original author or authors.
+#
+# Licensed 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.
+
+# AspectJ Weaver Agent configuration
+---
+enabled: true

config/components.yml

@@ -38,6 +38,7 @@ jres:
 # command after any Java Opts added by previous frameworks.
 frameworks:
   - "JavaBuildpack::Framework::AppDynamicsAgent"
+  - "JavaBuildpack::Framework::AspectjWeaverAgent"
   - "JavaBuildpack::Framework::ClientCertificateMapper"
   - "JavaBuildpack::Framework::ContainerCustomizer"
   - "JavaBuildpack::Framework::ContainerSecurityProvider"

docs/framework-aspectj_weaver_agent.md

@@ -0,0 +1,26 @@
+# AspectJ Weaver Agent Framework
+The AspectJ Weaver Agent Framework configures the AspectJ Runtime Weaving Agent at runtime.
+
+<table>
+  <tr>
+    <td><strong>Detection Criterion</strong></td>
+    <td><tt>aspectjweaver-*.jar</tt> existing and <tt>BOOT-INF/classes/META-INF/aop.xml</tt>, <tt>BOOT-INF/classes/org/aspectj/aop.xml</tt>, or <tt>META-INF/aop.xml</tt> existing.</td>
+  </tr>
+  <tr>
+    <td><strong>Tags</strong></td>
+    <td><tt>aspectj-weaver-agent=&lt;version&gt;</tt></td>
+  </tr>
+</table>
+Tags are printed to standard output by the buildpack detect script
+
+## Configuration
+For general information on configuring the buildpack, including how to specify configuration values through environment variables, refer to [Configuration and Extension][].
+
+The framework can be configured by creating or modifying the [`config/aspectj_weaver_agent.yml`][] file in the buildpack fork.
+
+| Name | Description
+| ---- | -----------
+| `enabled` | Whether to enable the AspectJ Runtime Weaving agent.
+
+[`config/aspectj_weaver_agent.yml`]: ../config/aspect_weaver_agent.yml
+[Configuration and Extension]: ../README.md#configuration-and-extension

lib/java_buildpack/framework/aspectj_weaver_agent.rb

@@ -0,0 +1,75 @@
+# Cloud Foundry Java Buildpack
+# Copyright 2013-2017 the original author or authors.
+#
+# Licensed 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.
+
+require 'java_buildpack/component/base_component'
+require 'java_buildpack/framework'
+require 'java_buildpack/util/dash_case'
+require 'java_buildpack/util/jar_finder'
+
+module JavaBuildpack
+  module Framework
+
+    # Encapsulates the functionality for contributing AspectJ Runtime Weaving configuration an application.
+    class AspectjWeaverAgent < JavaBuildpack::Component::BaseComponent
+
+      # Creates an instance.  In addition to the functionality inherited from +BaseComponent+, +@version+ and +@uri+
+      # instance variables are exposed.
+      #
+      # @param [Hash] context a collection of utilities used by components
+      def initialize(context)
+        super(context)
+
+        @jar_finder = JavaBuildpack::Util::JarFinder.new(/.*aspectjweaver-([\d].*)\.jar/)
+      end
+
+      # (see JavaBuildpack::Component::BaseComponent#detect)
+      def detect
+        supports? ? "#{self.class.to_s.dash_case}=#{@jar_finder.version(@application)}" : nil
+      end
+
+      # (see JavaBuildpack::Component::BaseComponent#compile)
+      def compile
+        puts "-----> AspectJ #{version} Runtime Weaving Enabled"
+      end
+
+      # (see JavaBuildpack::Component::BaseComponent#release)
+      def release
+        @droplet.java_opts.add_javaagent @jar_finder.is?(@application)
+      end
+
+      private
+
+      def aop_xml_exist?
+        (@application.root + 'BOOT-INF/classes/META-INF/aop.xml').exist? ||
+          (@application.root + 'BOOT-INF/classes/org/aspectj/aop.xml').exist? ||
+          (@application.root + 'META-INF/aop.xml').exist?
+      end
+
+      def enabled?
+        @configuration['enabled']
+      end
+
+      def supports?
+        enabled? && @jar_finder.is?(@application) && aop_xml_exist?
+      end
+
+      def version
+        @jar_finder.version(@application)
+      end
+
+    end
+
+  end
+end