Extract common integration framework for custom span decorator

opentracing-specialagent-util/src/main/java/io/opentracing/contrib/specialagent/InstrumentIntegration.java

@@ -0,0 +1,127 @@
+package io.opentracing.contrib.specialagent;
+
+import java.io.IOException;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class InstrumentIntegration {
+  private static String GLOBAL_CLASSPATH_OPT = "sa.integration.classpath";
+
+  private static final Logger logger = Logger.getLogger(InstrumentIntegration.class);
+
+  private static InstrumentIntegration SINGLETON;
+
+  private URLClassLoader GLOBAL;
+
+  private Map<String, URLClassLoader> extensionClassLoaders = new HashMap<>();
+
+  public static void init(final Map<String, String[]> extensionClasspaths) {
+    if (SINGLETON != null) {
+      SINGLETON.clear();
+    }
+    SINGLETON = new InstrumentIntegration(extensionClasspaths);
+  }
+
+  public static InstrumentIntegration getInstance() {
+    if (SINGLETON == null) {
+      init(null);
+    }
+    return SINGLETON;
+  }
+
+  private InstrumentIntegration(final Map<String, String[]> extensionClasspaths) {
+    if (extensionClasspaths != null) {
+      final String[] globalClasspaths = extensionClasspaths.get(GLOBAL_CLASSPATH_OPT);
+      if (GLOBAL == null && globalClasspaths != null) {
+        GLOBAL = this.createClassLoader(globalClasspaths, null);
+      }
+
+      for (final Map.Entry<String, String[]> entry : extensionClasspaths.entrySet()) {
+        extensionClassLoaders.put(entry.getKey(), this.createClassLoader(entry.getValue(), GLOBAL));
+      }
+    }
+  }
+
+  private URLClassLoader createClassLoader(final String[] classpaths, ClassLoader parent) {
+    final URL[] urls = new URL[classpaths.length];
+    for (int i = 0; i < classpaths.length; ++i) {
+      final String part = classpaths[i];
+      try {
+        urls[i] = new URL("file", "", part.endsWith(".jar") || part.endsWith("/") ? part : part + "/");
+      } catch (final MalformedURLException e) {
+        logger.log(Level.WARNING, part + "is not a valid URL");
+      }
+    }
+    return new URLClassLoader(urls, parent);
+  }
+
+  public <T> List<T> getExtensionInstances(Class<T> clazz, String extensionClasspathOpt, String... classNames) {
+    final ClassLoader classLoader = this.extensionClassLoaders.get(extensionClasspathOpt);
+    final List<T> result = new ArrayList<>();
+    if (classNames != null) {
+      for (final String className : classNames) {
+        final T object = newInstance(classLoader, clazz, className);
+        if (object != null)
+          result.add(object);
+      }
+    }
+    return result;
+  }
+
+  private <T> T newInstance(final ClassLoader classLoader, final Class<T> clazz, final String className) {
+    try {
+      Class<?> decoratorClass = loadClass(classLoader, className);
+      if (decoratorClass == null)
+        decoratorClass = loadClass(clazz.getClassLoader(), className);
+
+      if (decoratorClass == null)
+        return null;
+
+      if (clazz.isAssignableFrom(decoratorClass))
+        return clazz.cast(decoratorClass.newInstance());
+
+      logger.log(Level.WARNING, className + " is not a subclass of " + clazz.getName());
+    } catch (final InstantiationException | IllegalAccessException e) {
+      logger.log(Level.SEVERE, e.getMessage(), e);
+    }
+
+    return null;
+  }
+
+  private Class<?> loadClass(ClassLoader classLoader, String className) {
+    if (classLoader == null)
+      return null;
+
+    try {
+      return classLoader.loadClass(className);
+    } catch (final ClassNotFoundException e) {
+      logger.log(Level.SEVERE, e.getMessage(), e);
+    }
+
+    return null;
+  }
+
+  private void clear() {
+    if (this.GLOBAL != null) {
+      try {
+        this.GLOBAL.close();
+      } catch (IOException e) {
+        logger.finer("Closing classLoader fail: " + e.getMessage());
+      }
+      this.GLOBAL = null;
+    }
+    for (URLClassLoader classLoader : this.extensionClassLoaders.values()) {
+      try {
+        classLoader.close();
+      } catch (IOException e) {
+        logger.finer("Closing classLoader fail: " + e.getMessage());
+      }
+    }
+    this.extensionClassLoaders.clear();
+  }
+}

opentracing-specialagent-util/src/main/java/io/opentracing/contrib/specialagent/SpanDecoratorLoader.java

@@ -0,0 +1,39 @@
+package io.opentracing.contrib.specialagent;
+
+import java.util.Collections;
+import java.util.List;
+
+public class SpanDecoratorLoader<SD> {
+  public static final String DECORATOR_SEPARATOR = ",";
+  public static final String SPAN_DECORATORS_OPT_PREFIX = "sa.integration.";
+  public static final String SPAN_DECORATORS_CLASSPATH_OPT_SURFIX = ".spanDecorators.classpath";
+  public static final String SPAN_DECORATORS_OPT_SURFIX = ".spanDecorators";
+
+  private String spanDecoratorClasspathOpt;
+  private String spanDecoratorsOpt;
+  private Class<SD> spanDecoratorClass;
+
+  public static <SD> SpanDecoratorLoader<SD> newInstance(String ruleName, Class<SD> spanDecoratorClass) {
+    return new SpanDecoratorLoader<>(ruleName, spanDecoratorClass);
+  }
+
+  private SpanDecoratorLoader(String ruleName, Class<SD> spanDecoratorClass) {
+    this.spanDecoratorClass = spanDecoratorClass;
+    this.spanDecoratorClasspathOpt = SPAN_DECORATORS_OPT_PREFIX + ruleName + SPAN_DECORATORS_CLASSPATH_OPT_SURFIX;
+    this.spanDecoratorsOpt = SPAN_DECORATORS_OPT_PREFIX + ruleName + SPAN_DECORATORS_OPT_SURFIX;
+  }
+
+  public List<SD> getSpanDecorators(SD defultSpanDecorator) {
+    final String spanDecoratorsArgs = System.getProperty(spanDecoratorsOpt);
+    String[] spanDecoratorNames = null;
+    if (spanDecoratorsArgs != null) {
+      spanDecoratorNames = spanDecoratorsArgs.split(DECORATOR_SEPARATOR);
+    }
+    final List<SD> spanDecorators = InstrumentIntegration.getInstance().getExtensionInstances(this.spanDecoratorClass,
+        this.spanDecoratorClasspathOpt, spanDecoratorNames);
+    if (defultSpanDecorator != null && (spanDecorators == null || spanDecorators.isEmpty())) {
+      return Collections.singletonList(defultSpanDecorator);
+    }
+    return spanDecorators;
+  }
+}

opentracing-specialagent/src/main/java/io/opentracing/contrib/specialagent/SpecialAgent.java

@@ -201,6 +201,8 @@ private static void load(final Manager manager, final File[] ruleFiles, final Is
     final HashMap<String,Boolean> integrationRuleNameToEnable = new HashMap<>();
     final HashMap<String,Boolean> traceExporterNameToEnable = new HashMap<>();
     final File[] classPaths = SpecialAgentUtil.parseConfiguration(properties, verbosePluginNames, integrationRuleNameToEnable, traceExporterNameToEnable);
+    final Map<String, String[]> integrationClasspaths = SpecialAgentUtil.parseIntegrationConfiguration(properties);
+    InstrumentIntegration.init(integrationClasspaths);
 
     final boolean allIntegrationsEnabled = !integrationRuleNameToEnable.containsKey("*") || integrationRuleNameToEnable.remove("*");
     if (logger.isLoggable(Level.FINER))

opentracing-specialagent/src/main/java/io/opentracing/contrib/specialagent/SpecialAgentUtil.java

@@ -29,6 +29,7 @@
 import java.security.CodeSource;
 import java.util.Arrays;
 import java.util.Enumeration;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.LinkedHashSet;
@@ -81,6 +82,20 @@ else if (key.equals("sa.include")) {
     return includedPlugins;
   }
 
+  static Map<String, String[]> parseIntegrationConfiguration(final Map<String,String> properties) {
+    final HashMap<String,String[]> integrationClasspaths = new HashMap<>();
+    for (final Map.Entry<String,String> property : properties.entrySet()) {
+      final String key = property.getKey();
+      final String value = property.getValue();
+
+      if (key.contains("integration") && key.endsWith("classpath")) {
+        final String[] classpaths = value.split(File.pathSeparator);
+        integrationClasspaths.put(key, classpaths);
+      }
+    }
+    return integrationClasspaths;
+  }
+
   static JarFile createTempJarFile(final File dir) throws IOException {
     final Path dirPath = dir.toPath();
     final Path zipPath = Files.createTempFile("specialagent", ".jar");

rule/apache-httpclient/src/main/java/io/opentracing/contrib/specialagent/rule/apache/httpclient/Configuration.java

@@ -15,77 +15,15 @@
 
 package io.opentracing.contrib.specialagent.rule.apache.httpclient;
 
-import java.io.File;
-import java.net.MalformedURLException;
-import java.net.URL;
-import java.net.URLClassLoader;
-import java.util.ArrayList;
 import java.util.List;
 
-import io.opentracing.contrib.specialagent.Level;
-import io.opentracing.contrib.specialagent.Logger;
+import io.opentracing.contrib.specialagent.SpanDecoratorLoader;
 
 public class Configuration {
-  public static final Logger logger = Logger.getLogger(Configuration.class);
-  public static final String SPAN_DECORATORS = "sa.integration.apache:httpclient.spanDecorators";
-  public static final String SPAN_DECORATORS_CLASSPATH = "sa.integration.apache:httpclient.spanDecorators.classpath";
-  public static final String DECORATOR_SEPARATOR = ",";
+  public static final List<ApacheClientSpanDecorator> spanDecorators = parseSpanDecorators();
 
-  public static final List<ApacheClientSpanDecorator> spanDecorators = parseSpanDecorators(System.getProperty(SPAN_DECORATORS));
-  private static ClassLoader decoratorClassLoader;
-
-  static List<ApacheClientSpanDecorator> parseSpanDecorators(final String spanDecoratorsArgs) {
-    final List<ApacheClientSpanDecorator> result = new ArrayList<>();
-    if (spanDecoratorsArgs != null) {
-      final String[] parts = spanDecoratorsArgs.split(DECORATOR_SEPARATOR);
-      for (final String part : parts) {
-        final ApacheClientSpanDecorator decorator = newSpanDecoratorInstance(part);
-        if (decorator != null)
-          result.add(decorator);
-      }
-    }
-
-    if (result.isEmpty())
-      result.add(new ApacheClientSpanDecorator.StandardTags());
-
-    return result;
-  }
-
-  private static ApacheClientSpanDecorator newSpanDecoratorInstance(final String className) {
-    try {
-      final Class<?> decoratorClass = getDecoratorClassLoader().loadClass(className);
-      if (ApacheClientSpanDecorator.class.isAssignableFrom(decoratorClass))
-        return (ApacheClientSpanDecorator)decoratorClass.newInstance();
-
-      logger.log(Level.WARNING, className + " is not a subclass of " + ApacheClientSpanDecorator.class.getName());
-    }
-    catch (final ClassNotFoundException | IllegalAccessException | InstantiationException e) {
-      logger.log(Level.SEVERE, e.getMessage(), e);
-    }
-
-    return null;
-  }
-
-  private static ClassLoader getDecoratorClassLoader() {
-    if (decoratorClassLoader != null)
-      return decoratorClassLoader;
-
-    final String spanDecoratorsClassPath = System.getProperty(SPAN_DECORATORS_CLASSPATH);
-    if (spanDecoratorsClassPath == null || spanDecoratorsClassPath.isEmpty())
-      return decoratorClassLoader = ApacheClientSpanDecorator.class.getClassLoader();
-
-    final String[] parts = spanDecoratorsClassPath.split(File.pathSeparator);
-    final URL[] urls = new URL[parts.length];
-    for (int i = 0; i < parts.length; ++i) {
-      final String part = parts[i];
-      try {
-        urls[i] = new URL("file", "", part.endsWith(".jar") || part.endsWith("/") ? part : part + "/");
-      }
-      catch (final MalformedURLException e) {
-        logger.log(Level.WARNING, part + "is not a valid URL");
-      }
-    }
-
-    return decoratorClassLoader = new URLClassLoader(urls, ApacheClientSpanDecorator.class.getClassLoader());
+  static List<ApacheClientSpanDecorator> parseSpanDecorators() {
+    return SpanDecoratorLoader.newInstance("apache:httpclient", ApacheClientSpanDecorator.class)
+        .getSpanDecorators(new ApacheClientSpanDecorator.StandardTags());
   }
 }

rule/apache-httpclient/src/test/java/io/opentracing/contrib/specialagent/rule/apache/httpclient/ConfigurationTest.java

@@ -34,7 +34,10 @@ public void testImplicitSpanDecorators() {
   }
 
   private static void testDecorators(final String spanDecoratorsArgs, final Class<?> ... expecteds) {
-    final List<ApacheClientSpanDecorator> decorators = Configuration.parseSpanDecorators(spanDecoratorsArgs);
+    System.clearProperty("sa.integration.apache:httpclient.spanDecorators");
+    if(spanDecoratorsArgs != null)
+      System.setProperty("sa.integration.apache:httpclient.spanDecorators", spanDecoratorsArgs);
+    final List<ApacheClientSpanDecorator> decorators = Configuration.parseSpanDecorators();
     assertEquals(expecteds.length, decorators.size());
     final List<Class<?>> list = Arrays.asList(expecteds);
     for (final ApacheClientSpanDecorator decorator : decorators)

rule/apache-httpclient/src/test/java/io/opentracing/contrib/specialagent/rule/apache/httpclient/HttpClientTest.java

@@ -45,7 +45,8 @@ public void before(final MockTracer tracer) {
 
   @Test
   public void test(final MockTracer tracer) {
-    System.setProperty(Configuration.SPAN_DECORATORS, "io.opentracing.contrib.specialagent.rule.apache.httpclient.ApacheClientSpanDecorator$StandardTags,io.opentracing.contrib.specialagent.rule.apache.httpclient.MockSpanDecorator");
+    System.setProperty("sa.integration.apache:httpclient.spanDecorators",
+        "io.opentracing.contrib.specialagent.rule.apache.httpclient.ApacheClientSpanDecorator$StandardTags,io.opentracing.contrib.specialagent.rule.apache.httpclient.MockSpanDecorator");
 
     final CloseableHttpClient httpClient = HttpClients.createDefault();
     final String url = "http://localhost:12345";