From 6e9e41e6e7b53419279ffeefb2b4f81d0097ac1c Mon Sep 17 00:00:00 2001
From: Pranav Sharma <sharmapranav@google.com>
Date: Thu, 18 May 2023 01:09:42 +0000
Subject: [PATCH] Support metric exporter for cloud run

---
 .../metric/ResourceTranslator.java            | 37 ++++++++++++++++++-
 .../resource/ResourceTranslator.java          |  1 +
 2 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/exporters/metrics/src/main/java/com/google/cloud/opentelemetry/metric/ResourceTranslator.java b/exporters/metrics/src/main/java/com/google/cloud/opentelemetry/metric/ResourceTranslator.java
index 790f7713..db1c2495 100644
--- a/exporters/metrics/src/main/java/com/google/cloud/opentelemetry/metric/ResourceTranslator.java
+++ b/exporters/metrics/src/main/java/com/google/cloud/opentelemetry/metric/ResourceTranslator.java
@@ -18,9 +18,13 @@
 import com.google.api.MonitoredResource;
 import com.google.cloud.opentelemetry.resource.GcpResource;
 import io.opentelemetry.sdk.resources.Resource;
+import java.util.Map;
 
 /** Translates from OpenTelemetry Resource into Google Cloud Monitoring's MonitoredResource. */
 public class ResourceTranslator {
+  private static final String MR_CLOUD_RUN_REVISION = "cloud_run_revision";
+  private static final String MR_GENERIC_TASK = "generic_task";
+
   private ResourceTranslator() {}
 
   /** Converts a Java OpenTelemetry SDK resource into a MonitoredResource from GCP. */
@@ -28,8 +32,37 @@ public static MonitoredResource mapResource(Resource resource) {
     GcpResource gcpResource =
         com.google.cloud.opentelemetry.resource.ResourceTranslator.mapResource(resource);
     MonitoredResource.Builder mr = MonitoredResource.newBuilder();
-    mr.setType(gcpResource.getResourceType());
-    gcpResource.getResourceLabels().getLabels().forEach(mr::putLabels);
+    if (!mapCloudRunRevisionToGenericTask(mr, gcpResource)) {
+      // the gcpResource was not cloud_run_revision, so no explicit mapping performed
+      mr.setType(gcpResource.getResourceType());
+      gcpResource.getResourceLabels().getLabels().forEach(mr::putLabels);
+    }
     return mr.build();
   }
+
+  /**
+   * Helper function to map cloud_run_revision {@link MonitoredResource} to generic_task. This is
+   * done because custom metrics are not yet supported on cloud_run_revision. For details see <a
+   * href="https://cloud.google.com/monitoring/custom-metrics/creating-metrics#create-metric-desc">Manual
+   * creation of metric descriptors</a>.
+   *
+   * @param monitoredResourceBuilder Builder object for {@link MonitoredResource} which needs to be
+   *     mapped to generic_task.
+   * @param cloudRunResource The actual Cloud Run resource which is detected.
+   * @return True if the mapping operation was performed, indicating that the passed {@link
+   *     GcpResource} was cloud_run_revision. False otherwise.
+   */
+  private static boolean mapCloudRunRevisionToGenericTask(
+      MonitoredResource.Builder monitoredResourceBuilder, GcpResource cloudRunResource) {
+    if (cloudRunResource.getResourceType().equals(MR_CLOUD_RUN_REVISION)) {
+      monitoredResourceBuilder.setType(MR_GENERIC_TASK);
+      Map<String, String> cloudRunLabels = cloudRunResource.getResourceLabels().getLabels();
+      monitoredResourceBuilder.putLabels("location", cloudRunLabels.get("location"));
+      monitoredResourceBuilder.putLabels("namespace", cloudRunLabels.get("configuration_name"));
+      monitoredResourceBuilder.putLabels("job", cloudRunLabels.get("service_name"));
+      monitoredResourceBuilder.putLabels("task_id", cloudRunLabels.get("instance_id"));
+      return true;
+    }
+    return false;
+  }
 }
diff --git a/shared/resourcemapping/src/main/java/com/google/cloud/opentelemetry/resource/ResourceTranslator.java b/shared/resourcemapping/src/main/java/com/google/cloud/opentelemetry/resource/ResourceTranslator.java
index 1936015a..3bcad73f 100644
--- a/shared/resourcemapping/src/main/java/com/google/cloud/opentelemetry/resource/ResourceTranslator.java
+++ b/shared/resourcemapping/src/main/java/com/google/cloud/opentelemetry/resource/ResourceTranslator.java
@@ -93,6 +93,7 @@ public static AttributeMapping create(
           AttributeMapping.create("location", ResourceAttributes.CLOUD_REGION),
           AttributeMapping.create("service_name", ResourceAttributes.FAAS_NAME),
           AttributeMapping.create("configuration_name", ResourceAttributes.FAAS_NAME),
+          AttributeMapping.create("instance_id", ResourceAttributes.FAAS_ID),
           AttributeMapping.create("revision_name", ResourceAttributes.FAAS_VERSION));
   private static List<AttributeMapping> GOOGLE_CLOUD_FUNCTION_INSTANCE_LABELS =
       java.util.Arrays.asList(