Auto-detect service name from web.xml display-name

custom/src/main/java/com/splunk/opentelemetry/servicename/AppServerServiceNameDetector.java

@@ -0,0 +1,262 @@
+/*
+ * Copyright Splunk Inc.
+ *
+ * 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.
+ */
+
+package com.splunk.opentelemetry.servicename;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayDeque;
+import java.util.Deque;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipFile;
+import javax.annotation.Nullable;
+import javax.xml.parsers.ParserConfigurationException;
+import javax.xml.parsers.SAXParser;
+import javax.xml.parsers.SAXParserFactory;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.xml.sax.Attributes;
+import org.xml.sax.SAXException;
+import org.xml.sax.helpers.DefaultHandler;
+
+abstract class AppServerServiceNameDetector extends ServiceNameDetector {
+  private static final Logger log = LoggerFactory.getLogger(AppServerServiceNameDetector.class);
+
+  final ResourceLocator locator;
+  final Class<?> serverClass;
+  final boolean supportsEar;
+
+  AppServerServiceNameDetector(
+      ResourceLocator locator, String serverClassName, boolean supportsEar) {
+    this.locator = locator;
+    this.serverClass = locator.findClass(serverClassName);
+    this.supportsEar = supportsEar;
+  }
+
+  /** Use to ignore default applications that are bundled with the app server. */
+  boolean isValidAppName(Path path) {
+    return true;
+  }
+
+  /** Use to ignore default applications that are bundled with the app server. */
+  boolean isValidResult(Path path, @Nullable String result) {
+    return true;
+  }
+
+  /** Path to directory to be scanned for deployments. */
+  abstract Path getDeploymentDir() throws Exception;
+
+  @Override
+  String detect() throws Exception {
+    if (serverClass == null) {
+      return null;
+    }
+
+    Path deploymentDir = getDeploymentDir();
+    if (deploymentDir == null) {
+      return null;
+    }
+
+    if (Files.isDirectory(deploymentDir)) {
+      log.debug("Looking for deployments in '{}'.", deploymentDir);
+      try (Stream<Path> stream = Files.list(deploymentDir)) {
+        for (Path path : stream.collect(Collectors.toList())) {
+          String name = detectName(path);
+          if (name != null) {
+            return name;
+          }
+        }
+      }
+    } else {
+      log.debug("Deployment dir '{}' doesn't exist.", deploymentDir);
+    }
+
+    return null;
+  }
+
+  private String detectName(Path path) {
+    if (!isValidAppName(path)) {
+      log.debug("Skipping '{}'.", path);
+      return null;
+    }
+
+    log.debug("Attempting service name detection in '{}'.", path);
+    String name = path.getFileName().toString();
+    if (Files.isDirectory(path)) {
+      return handleExplodedApp(path);
+    } else if (name.endsWith(".war")) {
+      return handlePackagedWar(path);
+    } else if (supportsEar && name.endsWith(".ear")) {
+      return handlePackagedEar(path);
+    }
+
+    return null;
+  }
+
+  private String handleExplodedApp(Path path) {
+    {
+      String result = handleExplodedWar(path);
+      if (result != null) {
+        return result;
+      }
+    }
+    if (supportsEar) {
+      String result = handleExplodedEar(path);
+      if (result != null) {
+        return result;
+      }
+    }
+    return null;
+  }
+
+  private String handlePackagedWar(Path path) {
+    return handlePackaged(path, "WEB-INF/web.xml", new WebXmlHandler());
+  }
+
+  private String handlePackagedEar(Path path) {
+    return handlePackaged(path, "META-INF/application.xml", new ApplicationXmlHandler());
+  }
+
+  private String handlePackaged(Path path, String descriptorPath, DescriptorHandler handler) {
+    try (ZipFile zip = new ZipFile(path.toFile())) {
+      ZipEntry zipEntry = zip.getEntry(descriptorPath);
+      if (zipEntry != null) {
+        return handle(() -> zip.getInputStream(zipEntry), path, handler);
+      }
+    } catch (IOException exception) {
+      log.warn("Failed to read '{}' from zip '{}'.", descriptorPath, path, exception);
+    }
+
+    return null;
+  }
+
+  String handleExplodedWar(Path path) {
+    return handleExploded(path, path.resolve("WEB-INF/web.xml"), new WebXmlHandler());
+  }
+
+  String handleExplodedEar(Path path) {
+    return handleExploded(
+        path, path.resolve("META-INF/application.xml"), new ApplicationXmlHandler());
+  }
+
+  private String handleExploded(Path path, Path descriptor, DescriptorHandler handler) {
+    if (Files.isRegularFile(descriptor)) {
+      return handle(() -> Files.newInputStream(descriptor), path, handler);
+    }
+
+    return null;
+  }
+
+  private String handle(InputStreamSupplier supplier, Path path, DescriptorHandler handler) {
+    try {
+      try (InputStream inputStream = supplier.supply()) {
+        String candidate = parseDescriptor(inputStream, handler);
+        if (isValidResult(path, candidate)) {
+          return candidate;
+        }
+      }
+    } catch (Exception exception) {
+      log.warn("Failed to parse descriptor", exception);
+    }
+
+    return null;
+  }
+
+  private static String parseDescriptor(InputStream inputStream, DescriptorHandler handler)
+      throws ParserConfigurationException, SAXException, IOException {
+    if (SaxParserFactoryHolder.saxParserFactory == null) {
+      return null;
+    }
+    SAXParser saxParser = SaxParserFactoryHolder.saxParserFactory.newSAXParser();
+    saxParser.parse(inputStream, handler);
+    return handler.displayName;
+  }
+
+  private interface InputStreamSupplier {
+    InputStream supply() throws IOException;
+  }
+
+  private static class WebXmlHandler extends DescriptorHandler {
+
+    WebXmlHandler() {
+      super("web-app");
+    }
+  }
+
+  private static class ApplicationXmlHandler extends DescriptorHandler {
+
+    ApplicationXmlHandler() {
+      super("application");
+    }
+  }
+
+  private static class DescriptorHandler extends DefaultHandler {
+    private final String rootElementName;
+    private final Deque<String> currentElement = new ArrayDeque<>();
+    private boolean setDisplayName;
+    String displayName;
+
+    DescriptorHandler(String rootElementName) {
+      this.rootElementName = rootElementName;
+    }
+
+    @Override
+    public void startElement(String uri, String localName, String qName, Attributes attributes) {
+      if (displayName == null
+          && rootElementName.equals(currentElement.peek())
+          && "display-name".equals(qName)) {
+        String lang = attributes.getValue("xml:lang");
+        if (lang == null || "".equals(lang)) {
+          lang = "en"; // en is the default language
+        }
+        if ("en".equals(lang)) {
+          setDisplayName = true;
+        }
+      }
+      currentElement.push(qName);
+    }
+
+    @Override
+    public void endElement(String uri, String localName, String qName) {
+      currentElement.pop();
+      setDisplayName = false;
+    }
+
+    @Override
+    public void characters(char[] ch, int start, int length) {
+      if (setDisplayName) {
+        displayName = new String(ch, start, length);
+      }
+    }
+  }
+
+  private static class SaxParserFactoryHolder {
+    private static final SAXParserFactory saxParserFactory = getSaxParserFactory();
+
+    private static SAXParserFactory getSaxParserFactory() {
+      try {
+        return SAXParserFactory.newInstance();
+      } catch (Throwable throwable) {
+        log.debug("XML parser not available.", throwable);
+      }
+      return null;
+    }
+  }
+}

custom/src/main/java/com/splunk/opentelemetry/servicename/GlassfishServiceNameDetector.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright Splunk Inc.
+ *
+ * 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.
+ */
+
+package com.splunk.opentelemetry.servicename;
+
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+class GlassfishServiceNameDetector extends AppServerServiceNameDetector {
+
+  GlassfishServiceNameDetector(ResourceLocator locator) {
+    super(locator, "com.sun.enterprise.glassfish.bootstrap.ASMain", true);
+  }
+
+  @Override
+  Path getDeploymentDir() {
+    String instanceRoot = System.getProperty("com.sun.aas.instanceRoot");
+    if (instanceRoot == null) {
+      return null;
+    }
+
+    // besides autodeploy directory it is possible to deploy applications through admin console and
+    // asadmin script, to detect those we would need to parse config/domain.xml
+    return Paths.get(instanceRoot, "autodeploy");
+  }
+}

custom/src/main/java/com/splunk/opentelemetry/servicename/JettyServiceNameDetector.java

@@ -0,0 +1,91 @@
+/*
+ * Copyright Splunk Inc.
+ *
+ * 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.
+ */
+
+package com.splunk.opentelemetry.servicename;
+
+import com.google.common.annotations.VisibleForTesting;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+class JettyServiceNameDetector extends AppServerServiceNameDetector {
+  private static final Logger log = LoggerFactory.getLogger(JettyServiceNameDetector.class);
+
+  JettyServiceNameDetector(ResourceLocator locator) {
+    super(locator, "org.eclipse.jetty.start.Main", false);
+  }
+
+  @Override
+  boolean isValidAppName(Path path) {
+    // jetty deployer ignores directories ending with ".d"
+    if (Files.isDirectory(path)) {
+      return !path.getFileName().toString().endsWith(".d");
+    }
+    return true;
+  }
+
+  @VisibleForTesting
+  static Path parseJettyBase(String programArguments) {
+    if (programArguments == null) {
+      return null;
+    }
+    int start = programArguments.indexOf("jetty.base=");
+    if (start == -1) {
+      return null;
+    }
+    start += "jetty.base=".length();
+    if (start == programArguments.length()) {
+      return null;
+    }
+    // Take the path until the first space. If the path doesn't exist extend it up to the next
+    // space. Repeat until a path that exists is found or input runs out.
+    int next = start;
+    while (true) {
+      int nextSpace = programArguments.indexOf(' ', next);
+      if (nextSpace == -1) {
+        Path candidate = Paths.get(programArguments.substring(start));
+        return Files.exists(candidate) ? candidate : null;
+      }
+      Path candidate = Paths.get(programArguments.substring(start, nextSpace));
+      next = nextSpace + 1;
+      if (Files.exists(candidate)) {
+        return candidate;
+      }
+    }
+  }
+
+  @Override
+  Path getDeploymentDir() {
+    // Jetty expects the webapps directory to be in the directory where jetty was started from.
+    // Alternatively the location of webapps directory can be specified by providing jetty base
+    // directory as an argument to jetty e.g. java -jar start.jar jetty.base=/dir where webapps
+    // would be located in /dir/webapps.
+
+    String programArguments = System.getProperty("sun.java.command");
+    log.debug("Started with arguments '{}'.", programArguments);
+    if (programArguments != null) {
+      Path jettyBase = parseJettyBase(programArguments);
+      if (jettyBase != null) {
+        log.debug("Using jetty.base '{}'.", jettyBase);
+        return jettyBase.resolve("webapps");
+      }
+    }
+
+    return Paths.get("webapps").toAbsolutePath();
+  }
+}