Add new module for resource-detector support library

build.gradle

@@ -147,10 +147,11 @@ subprojects {
 		openTelemetryInstrumentationVersion = '1.31.0'
 		openTelemetrySemconvVersion = '1.22.0'
 		junitVersion = '4.13'
+		junit5Version = '5.10.0'
 		mockitoVersion = '3.5.10'
 		pubSubVersion = '1.125.11'
 		testContainersVersion = '1.15.1'
-		wiremockVersion = '2.27.2'
+		wiremockVersion = '2.35.0'
 		springWebVersion = '2.4.5'
 		springOpenFeignVersion = '3.0.0'
 		springOtelVersion = '1.0.0-M8'
@@ -194,6 +195,9 @@ subprojects {
 		testLibraries = [
 			assertj : "org.assertj:assertj-core:${assertjVersion}",
 			junit       : "junit:junit:${junitVersion}",
+			junit5 : "org.junit.jupiter:junit-jupiter-api:${junit5Version}",
+			junit5_runtime : "org.junit.jupiter:junit-jupiter-engine:${junit5Version}",
+			junit5_params : "org.junit.jupiter:junit-jupiter-params:${junit5Version}",
 			mockito     : "org.mockito:mockito-inline:${mockitoVersion}",
 			slf4j_simple: "org.slf4j:slf4j-simple:${slf4jVersion}",
 			opentelemetry_sdk_testing: "io.opentelemetry:opentelemetry-sdk-testing:${openTelemetryVersion}",

detectors/resources-support/build.gradle

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * 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.
+ */
+description = 'Support library for Google Cloud Resource Detector'
+
+dependencies {
+	testImplementation(testLibraries.assertj)
+	testImplementation(testLibraries.wiremock)
+	testImplementation(testLibraries.mockito)
+	testImplementation(testLibraries.junit5)
+	testImplementation(testLibraries.junit5_params)
+	testRuntimeOnly(testLibraries.junit5_runtime)
+}
+
+afterEvaluate {
+	tasks.named("compileJava"){
+		options.release = 8
+	}
+}
+
+test {
+	// required for discovering JUnit 5 tests
+	useJUnitPlatform()
+}

detectors/resources-support/src/main/java/com/google/cloud/opentelemetry/detectors/AttributeKeys.java

@@ -0,0 +1,64 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * 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.google.cloud.opentelemetry.detectors;
+
+/**
+ * Contains constants that act as keys for the known attributes for {@link
+ * com.google.cloud.opentelemetry.detectors.GCPPlatformDetector.SupportedPlatform}s.
+ */
+public final class AttributeKeys {
+  // GCE Attributes
+  public static final String GCE_PROJECT_ID = AttributeKeys.PROJECT_ID;
+  public static final String GCE_AVAILABILITY_ZONE = AttributeKeys.AVAILABILITY_ZONE;
+  public static final String GCE_CLOUD_REGION = AttributeKeys.CLOUD_REGION;
+  public static final String GCE_INSTANCE_ID = AttributeKeys.INSTANCE_ID;
+  public static final String GCE_INSTANCE_NAME = AttributeKeys.INSTANCE_NAME;
+  public static final String GCE_MACHINE_TYPE = AttributeKeys.MACHINE_TYPE;
+
+  // GKE Attributes
+  public static final String GKE_POD_NAME = "gke_pod_name";
+  public static final String GKE_NAMESPACE = "gke_namespace";
+  public static final String GKE_CONTAINER_NAME = "gke_container_name";
+  public static final String GKE_CLUSTER_NAME = "gke_cluster_name";
+  public static final String GKE_CLUSTER_LOCATION_TYPE = "gke_cluster_location_type";
+  public static final String GKE_CLUSTER_LOCATION = "gke_cluster_location";
+  public static final String GKE_HOST_ID = AttributeKeys.INSTANCE_ID;
+
+  // GKE Location Constants
+  public static final String GKE_LOCATION_TYPE_ZONE = "ZONE";
+  public static final String GKE_LOCATION_TYPE_REGION = "REGION";
+
+  // GAE Attributes
+  public static final String GAE_MODULE_NAME = "gae_module_name";
+  public static final String GAE_APP_VERSION = "gae_app_version";
+  public static final String GAE_INSTANCE_ID = AttributeKeys.INSTANCE_ID;
+  public static final String GAE_AVAILABILITY_ZONE = AttributeKeys.AVAILABILITY_ZONE;
+  public static final String GAE_CLOUD_REGION = AttributeKeys.CLOUD_REGION;
+
+  // Google Serverless Compute Attributes
+  public static final String SERVERLESS_COMPUTE_NAME = "serverless_compute_name";
+  public static final String SERVERLESS_COMPUTE_REVISION = "serverless_compute_revision";
+  public static final String SERVERLESS_COMPUTE_AVAILABILITY_ZONE = AttributeKeys.AVAILABILITY_ZONE;
+  public static final String SERVERLESS_COMPUTE_CLOUD_REGION = AttributeKeys.CLOUD_REGION;
+  public static final String SERVERLESS_COMPUTE_INSTANCE_ID = AttributeKeys.INSTANCE_ID;
+
+  static final String PROJECT_ID = "project_id";
+  static final String AVAILABILITY_ZONE = "availability_zone";
+  static final String CLOUD_REGION = "cloud_region";
+  static final String INSTANCE_ID = "instance_id";
+  static final String INSTANCE_NAME = "instance_name";
+  static final String MACHINE_TYPE = "machine_type";
+}

detectors/resources-support/src/main/java/com/google/cloud/opentelemetry/detectors/DetectedPlatform.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * 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.google.cloud.opentelemetry.detectors;
+
+import java.util.Map;
+
+/** Represents a GCP specific platform on which a cloud application can run. */
+public interface DetectedPlatform {
+  /**
+   * Method to retrieve the underlying compute platform on which application is running.
+   *
+   * @return the {@link GCPPlatformDetector.SupportedPlatform} representing the Google Cloud
+   *     platform on which application is running.
+   */
+  GCPPlatformDetector.SupportedPlatform getSupportedPlatform();
+
+  /**
+   * Method to retrieve the attributes associated with the compute platform on which the application
+   * is running as key-value pairs.
+   *
+   * @return a {@link Map} of attributes specific to the underlying compute platform.
+   */
+  Map<String, String> getAttributes();
+}

detectors/resources/src/main/java/com/google/cloud/opentelemetry/detectors/EnvVars.java → detectors/resources-support/src/main/java/com/google/cloud/opentelemetry/detectors/EnvironmentVariables.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2023 Google LLC
+ * Copyright 2024 Google LLC
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,8 +19,9 @@
  * Provides API to fetch environment variables. This is useful in order to create a mock class for
  * testing.
  */
-public interface EnvVars {
-  EnvVars DEFAULT_INSTANCE = System::getenv;
+interface EnvironmentVariables {
+  /** Returns the current environment variables of the platform this is running in. */
+  EnvironmentVariables DEFAULT_INSTANCE = System::getenv;
 
   /**
    * Grabs the system environment variable. Returns null on failure.

detectors/resources/src/main/java/com/google/cloud/opentelemetry/detectors/GCPMetadataConfig.java → detectors/resources-support/src/main/java/com/google/cloud/opentelemetry/detectors/GCPMetadataConfig.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2023 Google LLC
+ * Copyright 2024 Google LLC
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -32,28 +32,36 @@
  *     https://cloud.google.com/compute/docs/storing-retrieving-metadata</a>
  */
 final class GCPMetadataConfig {
-  private static final String DEFAULT_URL = "http://metadata.google.internal/computeMetadata/v1/";
-  public static final GCPMetadataConfig DEFAULT_INSTANCE = new GCPMetadataConfig(DEFAULT_URL);
+  static final GCPMetadataConfig DEFAULT_INSTANCE = new GCPMetadataConfig();
 
+  private static final String DEFAULT_URL = "http://metadata.google.internal/computeMetadata/v1/";
   private final String url;
   private final Map<String, String> cachedAttributes = new HashMap<>();
 
-  // For testing only
-  public GCPMetadataConfig(String url) {
-    this.url = url;
+  private GCPMetadataConfig() {
+    this.url = DEFAULT_URL;
   }
 
-  boolean isRunningOnGcp() {
-    return getProjectId() != null && !getProjectId().isEmpty();
+  // For testing only
+  GCPMetadataConfig(String url) {
+    this.url = url;
   }
 
   // Returns null on failure to retrieve from metadata server
   String getProjectId() {
     return getAttribute("project/project-id");
   }
 
-  // Example response: projects/640212054955/zones/australia-southeast1-a
-  // Returns null on failure to retrieve from metadata server
+  /**
+   * Method to extract cloud availability zone from the metadata server.
+   *
+   * <p>Example response: projects/640212054955/zones/australia-southeast1-a
+   *
+   * <p>Example zone: australia-southeast1-a
+   *
+   * @return the extracted zone from the metadata server response or null in case of failure to
+   *     retrieve from metadata server.
+   */
   String getZone() {
     String zone = getAttribute("instance/zone");
     if (zone != null && zone.contains("/")) {
@@ -62,10 +70,14 @@ String getZone() {
     return zone;
   }
 
-  // Use this method only when the region cannot be parsed from the zone. Known use-cases of this
-  // method involve detecting region in GAE standard environment
-  // Example response: projects/5689182099321/regions/us-central1
-  // Returns null on failure to retrieve from metadata server
+  /**
+   * Use this method only when the region cannot be parsed from the zone. Known use-cases of this
+   * method involve detecting region in GAE standard environment.
+   *
+   * <p>Example response: projects/5689182099321/regions/us-central1.
+   *
+   * @return the retrieved region or null in case of failure to retrieve from metadata server
+   */
   String getRegion() {
     String region = getAttribute("instance/region");
     if (region != null && region.contains("/")) {
@@ -74,6 +86,27 @@ String getRegion() {
     return region;
   }
 
+  /**
+   * Use this method to parse region from zone.
+   *
+   * <p>Example region: australia-southeast1
+   *
+   * @return parsed region from the zone, if zone is not found or is invalid, this method returns
+   *     null.
+   */
+  String getRegionFromZone() {
+    String region = null;
+    String zone = getZone();
+    if (zone != null && !zone.isEmpty()) {
+      // Parsing required to scope up to a region
+      String[] splitArr = zone.split("-");
+      if (splitArr.length > 2) {
+        region = String.join("-", splitArr[0], splitArr[1]);
+      }
+    }
+    return region;
+  }
+
   // Example response: projects/640212054955/machineTypes/e2-medium
   String getMachineType() {
     String machineType = getAttribute("instance/machine-type");

detectors/resources-support/src/main/java/com/google/cloud/opentelemetry/detectors/GCPPlatformDetector.java

@@ -0,0 +1,108 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * 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.google.cloud.opentelemetry.detectors;
+
+public class GCPPlatformDetector {
+  public static final GCPPlatformDetector DEFAULT_INSTANCE = new GCPPlatformDetector();
+
+  private final GCPMetadataConfig metadataConfig;
+  private final EnvironmentVariables environmentVariables;
+
+  // for testing only
+  GCPPlatformDetector(GCPMetadataConfig metadataConfig, EnvironmentVariables environmentVariables) {
+    this.metadataConfig = metadataConfig;
+    this.environmentVariables = environmentVariables;
+  }
+
+  private GCPPlatformDetector() {
+    this.metadataConfig = GCPMetadataConfig.DEFAULT_INSTANCE;
+    this.environmentVariables = EnvironmentVariables.DEFAULT_INSTANCE;
+  }
+
+  /**
+   * Detects the GCP platform on which the application is running.
+   *
+   * @return the specific GCP platform on which the application is running.
+   */
+  public DetectedPlatform detectPlatform() {
+    return generateDetectedPlatform(detectSupportedPlatform());
+  }
+
+  private SupportedPlatform detectSupportedPlatform() {
+    if (!isRunningOnGcp()) {
+      return SupportedPlatform.UNKNOWN_PLATFORM;
+    }
+    // Note: Order of detection matters here
+    if (environmentVariables.get("KUBERNETES_SERVICE_HOST") != null) {
+      return SupportedPlatform.GOOGLE_KUBERNETES_ENGINE;
+    } else if (environmentVariables.get("K_CONFIGURATION") != null
+        && environmentVariables.get("FUNCTION_TARGET") == null) {
+      return SupportedPlatform.GOOGLE_CLOUD_RUN;
+    } else if (environmentVariables.get("FUNCTION_TARGET") != null) {
+      return SupportedPlatform.GOOGLE_CLOUD_FUNCTIONS;
+    } else if (environmentVariables.get("GAE_SERVICE") != null) {
+      return SupportedPlatform.GOOGLE_APP_ENGINE;
+    }
+    return SupportedPlatform.GOOGLE_COMPUTE_ENGINE; // default to GCE
+  }
+
+  private boolean isRunningOnGcp() {
+    return metadataConfig.getProjectId() != null && !metadataConfig.getProjectId().isEmpty();
+  }
+
+  private DetectedPlatform generateDetectedPlatform(SupportedPlatform platform) {
+    DetectedPlatform detectedPlatform;
+    switch (platform) {
+      case GOOGLE_KUBERNETES_ENGINE:
+        detectedPlatform = new GoogleKubernetesEngine(environmentVariables, metadataConfig);
+        break;
+      case GOOGLE_CLOUD_RUN:
+        detectedPlatform = new GoogleCloudRun(environmentVariables, metadataConfig);
+        break;
+      case GOOGLE_CLOUD_FUNCTIONS:
+        detectedPlatform = new GoogleCloudFunction(environmentVariables, metadataConfig);
+        break;
+      case GOOGLE_APP_ENGINE:
+        detectedPlatform = new GoogleAppEngine(environmentVariables, metadataConfig);
+        break;
+      case GOOGLE_COMPUTE_ENGINE:
+        detectedPlatform = new GoogleComputeEngine(metadataConfig);
+        break;
+      default:
+        detectedPlatform = new UnknownPlatform();
+    }
+    return detectedPlatform;
+  }
+
+  /**
+   * SupportedPlatform represents the GCP platforms that can currently be detected by the
+   * resource-detector.
+   */
+  public enum SupportedPlatform {
+    /** Represents the Google Compute Engine platform. */
+    GOOGLE_COMPUTE_ENGINE,
+    /** Represents the Google Kubernetes Engine platform. */
+    GOOGLE_KUBERNETES_ENGINE,
+    /** Represents the Google App Engine platform. Could either be flex or standard. */
+    GOOGLE_APP_ENGINE,
+    /** Represents the Google Cloud Run platform. */
+    GOOGLE_CLOUD_RUN,
+    /** Represents the Google Cloud Functions platform. */
+    GOOGLE_CLOUD_FUNCTIONS,
+    /** Represents the case when the application is not running on GCP. */
+    UNKNOWN_PLATFORM,
+  }
+}