Add declarative config support for resource providers

instrumentation/resources/library/README.md

@@ -11,6 +11,8 @@ Provider: `io.opentelemetry.instrumentation.resources.ContainerResource`
 
 Specification: <https://github.com/open-telemetry/semantic-conventions/blob/main/docs/resource/container.md>
 
+Included in [declarative config].
+
 Implemented attributes:
 
 - `container.id`
@@ -21,6 +23,8 @@ Provider: `io.opentelemetry.instrumentation.resources.HostResource`
 
 Specification: <https://github.com/open-telemetry/semantic-conventions/blob/main/docs/resource/host.md>
 
+Included in [declarative config].
+
 Implemented attributes:
 
 - `host.name`
@@ -30,6 +34,8 @@ Provider: `io.opentelemetry.instrumentation.resources.HostIdResourceProvider`
 
 Specification: <https://github.com/open-telemetry/semantic-conventions/blob/main/docs/resource/host.md>
 
+Included in [declarative config].
+
 Implemented attributes:
 
 - `host.id`
@@ -40,6 +46,8 @@ Provider: `io.opentelemetry.instrumentation.resources.OsResource`
 
 Specification: <https://github.com/open-telemetry/semantic-conventions/blob/main/docs/resource/os.md>
 
+Included in [declarative config].
+
 Implemented attributes:
 
 - `os.type`
@@ -51,6 +59,8 @@ Implementation: `io.opentelemetry.instrumentation.resources.ProcessResource`
 
 Specification: <https://github.com/open-telemetry/semantic-conventions/blob/main/docs/resource/process.md#process>
 
+Included in [declarative config].
+
 Implemented attributes:
 
 - `process.pid`
@@ -63,6 +73,8 @@ Implementation: `io.opentelemetry.instrumentation.resources.ProcessRuntimeResour
 
 Specification: <https://github.com/open-telemetry/semantic-conventions/blob/main/docs/resource/process.md#process-runtimes>
 
+Included in [declarative config].
+
 Implemented attributes:
 
 - `process.runtime.name`
@@ -73,3 +85,5 @@ Implemented attributes:
 
 This package currently does not run on Android. It has been verified on OpenJDK and should work on
 other server JVM distributions but if you find any issues please let us know.
+
+[declarative config]: https://github.com/open-telemetry/opentelemetry-specification/tree/main/specification/configuration#declarative-configuration

instrumentation/resources/library/build.gradle.kts

@@ -12,6 +12,7 @@ dependencies {
   annotationProcessor("com.google.auto.service:auto-service")
   compileOnly("com.google.auto.service:auto-service-annotations")
   testCompileOnly("com.google.auto.service:auto-service-annotations")
+  testImplementation("io.opentelemetry:opentelemetry-sdk-extension-incubator")
 
   testImplementation("org.junit.jupiter:junit-jupiter-api")
 }

instrumentation/resources/library/src/main/java/io/opentelemetry/instrumentation/resources/HostIdResource.java

@@ -0,0 +1,172 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.instrumentation.resources;
+
+import static java.util.logging.Level.FINE;
+
+import io.opentelemetry.api.common.AttributeKey;
+import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.sdk.autoconfigure.spi.ResourceProvider;
+import io.opentelemetry.sdk.resources.Resource;
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.FileSystems;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Locale;
+import java.util.function.Function;
+import java.util.function.Supplier;
+import java.util.logging.Logger;
+
+/**
+ * {@link ResourceProvider} for automatically configuring <code>host.id</code> according to <a
+ * href="https://github.com/open-telemetry/semantic-conventions/blob/main/docs/resource/host.md#non-privileged-machine-id-lookup">the
+ * semantic conventions</a>
+ */
+public final class HostIdResource {
+
+  private static final Logger logger = Logger.getLogger(HostIdResource.class.getName());
+
+  // copied from HostIncubatingAttributes
+  static final AttributeKey<String> HOST_ID = AttributeKey.stringKey("host.id");
+
+  public static final String REGISTRY_QUERY =
+      "reg query HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Cryptography /v MachineGuid";
+
+  private static final HostIdResource INSTANCE =
+      new HostIdResource(
+          HostIdResource::getOsTypeSystemProperty,
+          HostIdResource::readMachineIdFile,
+          HostIdResource::queryWindowsRegistry);
+
+  private final Supplier<String> getOsType;
+  private final Function<Path, List<String>> machineIdReader;
+  private final Supplier<List<String>> queryWindowsRegistry;
+
+  // Visible for testing
+  HostIdResource(
+      Supplier<String> getOsType,
+      Function<Path, List<String>> machineIdReader,
+      Supplier<List<String>> queryWindowsRegistry) {
+    this.getOsType = getOsType;
+    this.machineIdReader = machineIdReader;
+    this.queryWindowsRegistry = queryWindowsRegistry;
+  }
+
+  /** Returns a {@link Resource} containing the {@code host.id} resource attribute. */
+  public static Resource get() {
+    return INSTANCE.createResource();
+  }
+
+  /** Returns a {@link Resource} containing the {@code host.id} resource attribute. */
+  Resource createResource() {
+    if (runningWindows()) {
+      return readWindowsGuid();
+    }
+    if (runningLinux()) {
+      return readLinuxMachineId();
+    }
+    logger.log(FINE, "Unsupported OS type: {0}", getOsType.get());
+    return Resource.empty();
+  }
+
+  private boolean runningLinux() {
+    return getOsType.get().toLowerCase(Locale.ROOT).equals("linux");
+  }
+
+  private boolean runningWindows() {
+    return getOsType.get().startsWith("Windows");
+  }
+
+  // see
+  // https://github.com/apache/commons-lang/blob/master/src/main/java/org/apache/commons/lang3/SystemUtils.java
+  // for values
+  private static String getOsTypeSystemProperty() {
+    return System.getProperty("os.name", "");
+  }
+
+  private Resource readLinuxMachineId() {
+    Path path = FileSystems.getDefault().getPath("/etc/machine-id");
+    List<String> lines = machineIdReader.apply(path);
+    if (lines.isEmpty()) {
+      return Resource.empty();
+    }
+    return Resource.create(Attributes.of(HOST_ID, lines.get(0)));
+  }
+
+  private static List<String> readMachineIdFile(Path path) {
+    try {
+      List<String> lines = Files.readAllLines(path);
+      if (lines.isEmpty()) {
+        logger.fine("Failed to read /etc/machine-id: empty file");
+      }
+      return lines;
+    } catch (IOException e) {
+      logger.log(FINE, "Failed to read /etc/machine-id", e);
+      return Collections.emptyList();
+    }
+  }
+
+  private Resource readWindowsGuid() {
+    List<String> lines = queryWindowsRegistry.get();
+
+    for (String line : lines) {
+      if (line.contains("MachineGuid")) {
+        String[] parts = line.trim().split("\\s+");
+        if (parts.length == 3) {
+          return Resource.create(Attributes.of(HOST_ID, parts[2]));
+        }
+      }
+    }
+    logger.fine("Failed to read Windows registry: No MachineGuid found in output: " + lines);
+    return Resource.empty();
+  }
+
+  private static List<String> queryWindowsRegistry() {
+    try {
+      ProcessBuilder processBuilder = new ProcessBuilder("cmd", "/c", REGISTRY_QUERY);
+      processBuilder.redirectErrorStream(true);
+      Process process = processBuilder.start();
+
+      List<String> output = getProcessOutput(process);
+      int exitedValue = process.waitFor();
+      if (exitedValue != 0) {
+        logger.fine(
+            "Failed to read Windows registry. Exit code: "
+                + exitedValue
+                + " Output: "
+                + String.join("\n", output));
+
+        return Collections.emptyList();
+      }
+
+      return output;
+    } catch (IOException | InterruptedException e) {
+      logger.log(FINE, "Failed to read Windows registry", e);
+      return Collections.emptyList();
+    }
+  }
+
+  private static List<String> getProcessOutput(Process process) throws IOException {
+    List<String> result = new ArrayList<>();
+
+    try (BufferedReader processOutputReader =
+        new BufferedReader(
+            new InputStreamReader(process.getInputStream(), StandardCharsets.UTF_8))) {
+      String readLine;
+
+      while ((readLine = processOutputReader.readLine()) != null) {
+        result.add(readLine);
+      }
+    }
+    return result;
+  }
+}