Refactor platform detection from resource provider

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

@@ -0,0 +1,86 @@
+/*
+ * Copyright 2023 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.Optional;
+
+/**
+ * Contains utility functions to retrieve appropriate zone and regions representing the location of
+ * certain cloud resources.
+ */
+final class CloudLocationUtil {
+  /**
+   * Utility method to extract cloud availability zone from passed {@link GCPMetadataConfig}. The
+   * method modifies the passed attributesBuilder by adding the extracted property to it. If the
+   * zone cannot be found, calling this method has no effect.
+   *
+   * <ul>
+   *   <li>If the availability zone cannot be found, calling this method has no effect.
+   * </ul>
+   *
+   * <p>Example zone: australia-southeast1-a
+   *
+   * @param metadataConfig The {@link GCPMetadataConfig} from which the cloud availability zone
+   *     value is extracted.
+   */
+  static Optional<String> getAvailabilityZoneFromMetadata(GCPMetadataConfig metadataConfig) {
+    return Optional.ofNullable(metadataConfig.getZone());
+  }
+
+  /**
+   * Utility method to extract the cloud region from passed {@link GCPMetadataConfig}. The method
+   * modifies the passed attributesBuilder by adding the extracted property to it.
+   *
+   * <ul>
+   *   <li>If the cloud region cannot be found, calling this method has no effect.
+   *   <li>This method uses zone attribute to parse region from it.
+   * </ul>
+   *
+   * <p>Example region: australia-southeast1
+   *
+   * @param metadataConfig The {@link GCPMetadataConfig} from which the cloud region value is
+   *     extracted.
+   */
+  static Optional<String> getCloudRegionFromMetadataUsingZone(GCPMetadataConfig metadataConfig) {
+    Optional<String> optZone = getAvailabilityZoneFromMetadata(metadataConfig);
+    if (optZone.isPresent()) {
+      // Parsing required to scope up to a region
+      String[] splitArr = optZone.get().split("-");
+      if (splitArr.length > 2) {
+        return Optional.of(String.join("-", splitArr[0], splitArr[1]));
+      }
+    }
+    return Optional.empty();
+  }
+
+  /**
+   * Utility method to extract the cloud region from passed {@link GCPMetadataConfig}. The method
+   * modifies the passed attributesBuilder by adding the extracted property to it.
+   *
+   * <ul>
+   *   <li>If the cloud region cannot be found, calling this method has no effect.
+   *   <li>This method directly uses the region attribute from the metadata config.
+   * </ul>
+   *
+   * <p>Example region: australia-southeast1
+   *
+   * @param metadataConfig The {@link GCPMetadataConfig} from which the cloud region value is
+   *     extracted.
+   */
+  static Optional<String> getCloudRegionFromMetadataUsingRegion(GCPMetadataConfig metadataConfig) {
+    return Optional.ofNullable(metadataConfig.getRegion());
+  }
+}

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

@@ -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;
+public 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-support/src/main/java/com/google/cloud/opentelemetry/detectors/GAEDetector.java

@@ -0,0 +1,63 @@
+/*
+ * Copyright 2023 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.Optional;
+
+public final class GAEDetector {
+  public static final GAEDetector DEFAULT_INSTANCE = new GAEDetector();
+
+  private final EnvironmentVariables environmentVariables;
+  private final GCPMetadataConfig metadataConfig;
+
+  GAEDetector() {
+    this.environmentVariables = EnvironmentVariables.DEFAULT_INSTANCE;
+    this.metadataConfig = GCPMetadataConfig.DEFAULT_INSTANCE;
+  }
+
+  // for testing only
+  GAEDetector(EnvironmentVariables environmentVariables, GCPMetadataConfig metadataConfig) {
+    this.environmentVariables = environmentVariables;
+    this.metadataConfig = metadataConfig;
+  }
+
+  public Optional<String> getAppModuleName() {
+    return Optional.ofNullable(this.environmentVariables.get("GAE_SERVICE"));
+  }
+
+  public Optional<String> getAppVersion() {
+    return Optional.ofNullable(this.environmentVariables.get("GAE_VERSION"));
+  }
+
+  public Optional<String> getAppInstanceId() {
+    return Optional.ofNullable(this.environmentVariables.get("GAE_INSTANCE"));
+  }
+
+  public Optional<String> getAvailabilityZone() {
+    return CloudLocationUtil.getAvailabilityZoneFromMetadata(this.metadataConfig);
+  }
+
+  public Optional<String> getCloudRegion() {
+    if (this.environmentVariables.get("GAE_ENV") == null) {
+      return Optional.empty();
+    }
+    if (this.environmentVariables.get("GAE_ENV").equals("standard")) {
+      return CloudLocationUtil.getCloudRegionFromMetadataUsingRegion(this.metadataConfig);
+    } else {
+      return CloudLocationUtil.getCloudRegionFromMetadataUsingZone(this.metadataConfig);
+    }
+  }
+}

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

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2023 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.Optional;
+
+public final class GCEDetector {
+  public static final GCEDetector DEFAULT_INSTANCE = new GCEDetector();
+
+  private final GCPMetadataConfig metadataConfig;
+
+  GCEDetector() {
+    this.metadataConfig = GCPMetadataConfig.DEFAULT_INSTANCE;
+  }
+
+  // for testing only
+  GCEDetector(GCPMetadataConfig metadataConfig) {
+    this.metadataConfig = metadataConfig;
+  }
+
+  public Optional<String> getProjectId() {
+    return Optional.ofNullable(this.metadataConfig.getProjectId());
+  }
+
+  public Optional<String> getAvailabilityZone() {
+    return CloudLocationUtil.getAvailabilityZoneFromMetadata(this.metadataConfig);
+  }
+
+  public Optional<String> getCloudRegion() {
+    return CloudLocationUtil.getCloudRegionFromMetadataUsingZone(this.metadataConfig);
+  }
+
+  public Optional<String> getInstanceId() {
+    return Optional.ofNullable(this.metadataConfig.getInstanceId());
+  }
+
+  public Optional<String> getInstanceName() {
+    return Optional.ofNullable(this.metadataConfig.getInstanceName());
+  }
+
+  public Optional<String> getMachineType() {
+    return Optional.ofNullable(this.metadataConfig.getMachineType());
+  }
+}

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

@@ -31,30 +31,30 @@
  * @see <a href="https://cloud.google.com/compute/docs/storing-retrieving-metadata">
  *     https://cloud.google.com/compute/docs/storing-retrieving-metadata</a>
  */
-public 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);
+final class GCPMetadataConfig {
+  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;
   }
 
-  public 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
-  public String getProjectId() {
+  String getProjectId() {
     return getAttribute("project/project-id");
   }
 
   // Example response: projects/640212054955/zones/australia-southeast1-a
   // Returns null on failure to retrieve from metadata server
-  public String getZone() {
+  String getZone() {
     String zone = getAttribute("instance/zone");
     if (zone != null && zone.contains("/")) {
       zone = zone.substring(zone.lastIndexOf('/') + 1);
@@ -66,7 +66,7 @@ public String getZone() {
   // method involve detecting region in GAE standard environment
   // Example response: projects/5689182099321/regions/us-central1
   // Returns null on failure to retrieve from metadata server
-  public String getRegion() {
+  String getRegion() {
     String region = getAttribute("instance/region");
     if (region != null && region.contains("/")) {
       region = region.substring(region.lastIndexOf('/') + 1);
@@ -75,7 +75,7 @@ public String getRegion() {
   }
 
   // Example response: projects/640212054955/machineTypes/e2-medium
-  public String getMachineType() {
+  String getMachineType() {
     String machineType = getAttribute("instance/machine-type");
     if (machineType != null && machineType.contains("/")) {
       machineType = machineType.substring(machineType.lastIndexOf('/') + 1);
@@ -84,27 +84,27 @@ public String getMachineType() {
   }
 
   // Returns null on failure to retrieve from metadata server
-  public String getInstanceId() {
+  String getInstanceId() {
     return getAttribute("instance/id");
   }
 
   // Returns null on failure to retrieve from metadata server
-  public String getClusterName() {
+  String getClusterName() {
     return getAttribute("instance/attributes/cluster-name");
   }
 
   // Returns null on failure to retrieve from metadata server
-  public String getClusterLocation() {
+  String getClusterLocation() {
     return getAttribute("instance/attributes/cluster-location");
   }
 
   // Returns null on failure to retrieve from metadata server
-  public String getInstanceHostName() {
+  String getInstanceHostName() {
     return getAttribute("instance/hostname");
   }
 
   // Returns null on failure to retrieve from metadata server
-  public String getInstanceName() {
+  String getInstanceName() {
     return getAttribute("instance/name");
   }