jooby-run: redo classloader strategy

jooby-run (maven/gradle) run on top of jboss-modules. As today it uses a single classloader that contains the project classpath + any project dependency (jars). Every time a change is done, jooby restarts the application, drop the classloader and creates a new classloader. This works OK but consumes memory due it must load all classes again. Next release will change this by using two classloaders: main: All project classes will be here. jars: All external dependencies will be here. Then on class change, we are doing to drop/re-create the main class loader only. ALL the external classes will remain the same. This changes not only will reduce the memory usage on development but also makes application restart lot faster (of course). fixes #3018
jooby-project · Jul 16, 2023 · 0224265 · 0224265
1 parent 3c07eab
commit 0224265
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diff --git a/modules/jooby-bom/pom.xml b/modules/jooby-bom/pom.xml
@@ -317,7 +317,7 @@
       <plugin>
         <groupId>com.diffplug.spotless</groupId>
         <artifactId>spotless-maven-plugin</artifactId>
-        <version>2.37.0</version>
+        <version>2.27.2</version>
         <configuration>
           <skip>true</skip>
         </configuration>

diff --git a/modules/jooby-run/pom.xml b/modules/jooby-run/pom.xml
@@ -78,6 +78,37 @@
           </archive>
         </configuration>
       </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-dependency-plugin</artifactId>
+        <version>3.6.0</version>
+        <executions>
+          <execution>
+            <id>copy</id>
+            <phase>generate-resources</phase>
+            <goals>
+              <goal>copy</goal>
+            </goals>
+            <configuration>
+              <outputDirectory>${project.build.directory}${file.separator}app${file.separator}libs</outputDirectory>
+              <artifactItems>
+                <artifactItem>
+                  <groupId>io.jooby</groupId>
+                  <artifactId>jooby</artifactId>
+                  <version>3.0.0</version>
+                  <overWrite>true</overWrite>
+                </artifactItem>
+                <artifactItem>
+                  <groupId>io.jooby</groupId>
+                  <artifactId>jooby-netty</artifactId>
+                  <version>3.0.0</version>
+                  <overWrite>true</overWrite>
+                </artifactItem>
+              </artifactItems>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
     </plugins>
   </build>
 

diff --git a/...n/java/io/jooby/run/FlattenClasspath.java → .../java/io/jooby/run/JoobyModuleFinder.java b/...n/java/io/jooby/run/FlattenClasspath.java → .../java/io/jooby/run/JoobyModuleFinder.java
@@ -5,33 +5,36 @@
  */
 package io.jooby.run;
 
+import static java.util.Collections.emptySet;
+import static java.util.Collections.singleton;
+
+import java.io.File;
 import java.io.IOException;
 import java.net.JarURLConnection;
 import java.net.URISyntaxException;
 import java.net.URL;
 import java.nio.file.Path;
 import java.nio.file.Paths;
-import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.Set;
 
 import org.jboss.modules.ModuleFinder;
-import org.jboss.modules.ModuleLoadException;
 import org.jboss.modules.ModuleLoader;
 import org.jboss.modules.ModuleSpec;
 
-class FlattenClasspath implements ModuleFinder {
-
+class JoobyModuleFinder implements ModuleFinder {
+  private static final String JARS = "jars";
   private final Set<Path> resources;
+  private final Set<Path> jars;
   private final String name;
 
-  FlattenClasspath(String name, Set<Path> resources, Set<Path> dependencies) {
+  JoobyModuleFinder(String name, Set<Path> resources, Set<Path> jars) {
     this.name = name;
-    this.resources = new LinkedHashSet<>(resources.size() + dependencies.size());
+    this.resources = new LinkedHashSet<>(resources.size() + 1);
     this.resources.addAll(resources);
-
     this.resources.add(joobyRunHook(getClass()));
-    this.resources.addAll(dependencies);
+
+    this.jars = jars;
   }
 
   /**
@@ -51,12 +54,30 @@ static Path joobyRunHook(Class loader) {
   }
 
   @Override
-  public ModuleSpec findModule(String name, ModuleLoader delegateLoader)
-      throws ModuleLoadException {
+  public ModuleSpec findModule(String name, ModuleLoader delegateLoader) {
     if (this.name.equals(name)) {
-      return Specs.spec(name, resources, Collections.emptySet());
+      return ModuleSpecHelper.create(name, resources, singleton(JARS));
+    } else if (JARS.equals(name)) {
+      return ModuleSpecHelper.create(name, jars, emptySet());
     }
 
     return null;
   }
+
+  @Override
+  public String toString() {
+    var buffer = new StringBuilder();
+    resources.stream()
+        .forEach(
+            it -> {
+              if (!buffer.isEmpty()) {
+                buffer.append(File.pathSeparator);
+              }
+              buffer.append(it);
+            });
+    if (!jars.isEmpty()) {
+      buffer.append("; jars: ").append(jars);
+    }
+    return buffer.toString();
+  }
 }
diff --git a/modules/jooby-run/src/main/java/io/jooby/run/JoobyModuleLoader.java b/modules/jooby-run/src/main/java/io/jooby/run/JoobyModuleLoader.java
@@ -0,0 +1,21 @@
+/*
+ * Jooby https://jooby.io
+ * Apache License Version 2.0 https://jooby.io/LICENSE.txt
+ * Copyright 2014 Edgar Espina
+ */
+package io.jooby.run;
+
+import org.jboss.modules.Module;
+import org.jboss.modules.ModuleFinder;
+import org.jboss.modules.ModuleLoader;
+
+class JoobyModuleLoader extends ModuleLoader {
+
+  JoobyModuleLoader(ModuleFinder finder) {
+    super(finder);
+  }
+
+  public void unload(String name, final Module module) {
+    super.unloadModuleLocal(name, module);
+  }
+}
diff --git a/modules/jooby-run/src/main/java/io/jooby/run/JoobyRun.java b/modules/jooby-run/src/main/java/io/jooby/run/JoobyRun.java
@@ -29,8 +29,6 @@
 
 import org.jboss.modules.Module;
 import org.jboss.modules.ModuleClassLoader;
-import org.jboss.modules.ModuleFinder;
-import org.jboss.modules.ModuleLoader;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -49,28 +47,11 @@
  */
 public class JoobyRun {
 
-  private static class Event {
-    private final long time;
-
-    Event(long time) {
-      this.time = time;
-    }
-  }
-
-  private static class ExtModuleLoader extends ModuleLoader {
-
-    ExtModuleLoader(ModuleFinder... finders) {
-      super(finders);
-    }
-
-    public void unload(String name, final Module module) {
-      super.unloadModuleLocal(name, module);
-    }
-  }
+  private record Event(long time) {}
 
   private static class AppModule {
     private final Logger logger;
-    private final ExtModuleLoader loader;
+    private final JoobyModuleLoader loader;
     private final JoobyRunOptions conf;
     private Module module;
     private ClassLoader contextClassLoader;
@@ -85,7 +66,7 @@ private static class AppModule {
 
     AppModule(
         Logger logger,
-        ExtModuleLoader loader,
+        JoobyModuleLoader loader,
         ClassLoader contextClassLoader,
         JoobyRunOptions conf) {
       this.logger = logger;
@@ -118,7 +99,6 @@ public Exception start() {
         if (port != null) {
           args.add("server.port=" + port);
         }
-        args.add("server.join=false");
         module.run(conf.getMainClass(), args.toArray(new String[0]));
       } catch (ClassNotFoundException x) {
         String message = x.getMessage();
@@ -147,6 +127,7 @@ public Exception start() {
     }
 
     private void printErr(Throwable source) {
+      source.printStackTrace();
       Throwable cause = withoutReflection(source);
       StackTraceElement[] stackTrace = cause.getStackTrace();
       int truncateAt = stackTrace.length;
@@ -361,14 +342,14 @@ public void start() throws Throwable {
               .map(Path::toString)
               .collect(Collectors.joining(File.pathSeparator));
       System.setProperty("jooby.run.classpath", classPathString);
+      var finder = new JoobyModuleFinder(options.getProjectName(), resources, dependencies);
 
-      ModuleFinder[] finders = {
-        new FlattenClasspath(options.getProjectName(), resources, dependencies)
-      };
-
-      ExtModuleLoader loader = new ExtModuleLoader(finders);
       module =
-          new AppModule(logger, loader, Thread.currentThread().getContextClassLoader(), options);
+          new AppModule(
+              logger,
+              new JoobyModuleLoader(finder),
+              Thread.currentThread().getContextClassLoader(),
+              options);
       ScheduledExecutorService se;
       Exception error = module.start();
       if (error == null) {
@@ -474,7 +455,7 @@ private void onFileChange(DirectoryChangeEvent.EventType kind, Path path) {
   }
 
   @SuppressWarnings("unchecked")
-  private static <E extends Throwable> void sneakyThrow0(final Throwable x) throws E {
+  public static <E extends Throwable> E sneakyThrow0(final Throwable x) throws E {
     throw (E) x;
   }
 }
diff --git a/...run/src/main/java/io/jooby/run/Specs.java → ...n/java/io/jooby/run/ModuleSpecHelper.java b/...run/src/main/java/io/jooby/run/Specs.java → ...n/java/io/jooby/run/ModuleSpecHelper.java
@@ -17,29 +17,41 @@
 
 import org.jboss.modules.DependencySpec;
 import org.jboss.modules.ModuleDependencySpecBuilder;
-import org.jboss.modules.ModuleLoadException;
 import org.jboss.modules.ModuleSpec;
 import org.jboss.modules.PathUtils;
 import org.jboss.modules.ResourceLoaderSpec;
 import org.jboss.modules.filter.PathFilters;
 
-final class Specs {
+final class ModuleSpecHelper {
 
-  private Specs() {}
+  private ModuleSpecHelper() {}
 
-  static DependencySpec metaInf(String moduleName) {
-    return new ModuleDependencySpecBuilder()
-        .setImportFilter(PathFilters.acceptAll())
-        .setExportFilter(PathFilters.getMetaInfServicesFilter())
-        .setName(moduleName)
-        .setOptional(false)
-        .build();
+  public static ModuleSpec create(String name, Set<Path> resources, Set<String> dependencies) {
+    ModuleSpec.Builder builder = newModule(name, resources);
+
+    // dependencies
+    for (String dependency : dependencies) {
+      builder.addDependency(
+          new ModuleDependencySpecBuilder()
+              .setImportFilter(PathFilters.acceptAll())
+              .setExportFilter(PathFilters.getMetaInfServicesFilter())
+              .setName(dependency)
+              .setOptional(false)
+              .build());
+    }
+    return builder.create();
   }
 
-  public static ModuleSpec spec(String name, Set<Path> resources, Set<String> dependencies)
-      throws ModuleLoadException {
+  private static ModuleSpec.Builder newModule(String name, Set<Path> resources) {
     try {
       ModuleSpec.Builder builder = ModuleSpec.build(name);
+      // Add all JDK classes
+      builder.addDependency(DependencySpec.createSystemDependencySpec(PathUtils.getPathSet(null)));
+      // needed, so that the module can load classes from the resource root
+      builder.addDependency(DependencySpec.createLocalDependencySpec());
+      // Add the module's own content
+      builder.addDependency(DependencySpec.OWN_DEPENDENCY);
+
       for (Path path : resources) {
         if (Files.isDirectory(path)) {
           builder.addResourceRoot(
@@ -49,18 +61,9 @@ public static ModuleSpec spec(String name, Set<Path> resources, Set<String> depe
               createResourceLoaderSpec(createJarResourceLoader(new JarFile(path.toFile()))));
         }
       }
-
-      // needed, so that the module can load classes from the resource root
-      builder.addDependency(DependencySpec.createLocalDependencySpec());
-      // add dependency on the JDK paths
-      builder.addDependency(DependencySpec.createSystemDependencySpec(PathUtils.getPathSet(null)));
-      // dependencies
-      for (String dependency : dependencies) {
-        builder.addDependency(Specs.metaInf(dependency));
-      }
-      return builder.create();
+      return builder;
     } catch (IOException x) {
-      throw new ModuleLoadException(name, x);
+      throw JoobyRun.sneakyThrow0(x);
     }
   }
 }