Fix monitoring in Embedded GlassFish

Requires running with flashlight-agent on command line with -javaagent:flashlight-agent.jar
When started with command "enable-monitoring --mbean true", metric will be available via JMX beans

Author: OndroMih

appserver/extras/embedded/all/pom.xml

@@ -127,6 +127,17 @@
                 </executions>
             </plugin>
 
+            <plugin>
+                <groupId>org.codehaus.gmaven</groupId>
+                <artifactId>groovy-maven-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <id>merge-manifest-values-to-properties</id>
+                        <phase>prepare-package</phase>
+                    </execution>
+                </executions>
+            </plugin>
+
             <plugin>
                 <artifactId>maven-assembly-plugin</artifactId>
                 <executions>
@@ -168,6 +179,7 @@
                                     <Main-Class>org.glassfish.runnablejar.UberMain</Main-Class>
                                     <Add-Opens>java.base/java.lang java.base/java.io java.base/java.util java.base/sun.nio.fs java.base/sun.net.www.protocol.jrt java.naming/javax.naming.spi java.rmi/sun.rmi.transport jdk.management/com.sun.management.internal java.base/jdk.internal.vm.annotation</Add-Opens>
                                     <Add-Exports>java.naming/com.sun.jndi.ldap java.base/jdk.internal.vm.annotation</Add-Exports>
+                                    <probe-provider-class-names>${probe.provider.class.names}</probe-provider-class-names>
                                 </manifestEntries>
                             </archive>
                         </configuration>

appserver/extras/embedded/pom.xml

@@ -16,7 +16,6 @@
     SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 
 -->
-
 <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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
 
@@ -52,4 +51,62 @@
         </dependencies>
     </dependencyManagement>
 
+    <build>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <groupId>org.codehaus.gmaven</groupId>
+                    <artifactId>groovy-maven-plugin</artifactId>
+                    <executions>
+                        <execution>
+                            <!-- Merges all values in the 'probe-provider-class-names'
+
+                                attribute into a system property 'probe.provider.class.names',
+
+                                which be used when building the final manifest
+                            -->
+                            <id>merge-manifest-values-to-properties</id>
+                            <goals>
+                                <goal>execute</goal>
+                            </goals>
+                            <configuration>
+                                <source>
+                                    import java.util.jar.JarFile
+                                    import java.util.jar.Manifest
+
+                                    def probeProviders = [] as Set
+
+                                    project.artifacts.each { artifact ->
+                                        if (artifact.type == 'jar') {
+                                            try {
+                                                def jar = new JarFile(artifact.file)
+                                                def manifest = jar.manifest
+                                                if (manifest) {
+                                                    def probeValue = manifest.mainAttributes.getValue('probe-provider-class-names')
+                                                    if (probeValue) {
+                                                        probeProviders.add(probeValue)
+                                                    }
+                                                }
+                                                jar.close()
+                                            } catch (Exception e) {
+                                                // Ignore invalid JARs
+                                            }
+                                        }
+                                    }
+
+                                    if (probeProviders) {
+                                        project.properties['probe.provider.class.names'] = probeProviders.join(',')
+                                        println "Found ${probeProviders.size()} probe providers in project dependencies"
+                                    } else {
+                                        println "No probe providers found in project dependencies"
+                                    }
+                                </source>
+                            </configuration>
+                        </execution>
+                    </executions>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+    </build>
+
 </project>

appserver/extras/embedded/web/pom.xml

@@ -113,6 +113,17 @@
                 </executions>
             </plugin>
 
+            <plugin>
+                <groupId>org.codehaus.gmaven</groupId>
+                <artifactId>groovy-maven-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <id>merge-manifest-values-to-properties</id>
+                        <phase>prepare-package</phase>
+                    </execution>
+                </executions>
+            </plugin>
+
             <plugin>
                 <artifactId>maven-assembly-plugin</artifactId>
                 <executions>
@@ -192,6 +203,7 @@
                                     <Main-Class>org.glassfish.runnablejar.UberMain</Main-Class>
                                     <Add-Opens>java.base/java.lang java.base/java.io java.base/java.util java.base/sun.nio.fs java.base/sun.net.www.protocol.jrt java.naming/javax.naming.spi java.rmi/sun.rmi.transport jdk.management/com.sun.management.internal java.base/jdk.internal.vm.annotation</Add-Opens>
                                     <Add-Exports>java.naming/com.sun.jndi.ldap java.base/jdk.internal.vm.annotation</Add-Exports>
+                                    <probe-provider-class-names>${probe.provider.class.names}</probe-provider-class-names>
                                 </manifestEntries>
                             </archive>
                         </configuration>

nucleus/flashlight/framework/src/main/java/org/glassfish/flashlight/cli/EnableMonitoring.java

@@ -126,7 +126,7 @@ public void execute(AdminCommandContext context) {
          if (!AgentAttacher.attachAgent(pidInt, options)) {
             ActionReport.MessagePart part = report.getTopMessagePart().addChild();
             part.setMessage(localStrings.getLocalString("attach.agent.exception",
-                    "Can't attach the agent to the JVM."));
+                    "Can't attach the agent to the JVM. Restart with the flash-light agent attached by the -javaagent command line parameter"));
             report.setActionExitCode(ActionReport.ExitCode.FAILURE);
             return;
         }

nucleus/flashlight/framework/src/main/java/org/glassfish/flashlight/impl/client/AgentAttacherInternal.java

@@ -48,13 +48,22 @@ static boolean attachAgent() {
         return attachAgent(-1, "");
     }
 
+    private static final String AGENT_CLASSNAME = "org.glassfish.flashlight.agent.ProbeAgentMain";
     static boolean attachAgent(long pid, String options) {
         try {
             if (isAttached) {
                 return true;
             }
 
             if (pid < 0) {
+
+                try {
+                    ClassLoader.getSystemClassLoader().loadClass(AGENT_CLASSNAME);
+                    isAttached = true;
+                    return true;
+                } catch (Throwable t) {
+                }
+
                 pid = ProcessHandle.current().pid();
             }