Configured Project ID takes precedence over Project ID of project in …

…which the code is running for using as log writing target.

apis/Google.Cloud.Logging.NLog/Google.Cloud.Logging.NLog.Tests/GoogleStackdriverTargetTest.cs

@@ -508,6 +508,7 @@ public async Task UnknownPlatform()
             Assert.Equal("global", r.Type);
             Assert.Equal(1, r.Labels.Count);
             Assert.Equal(s_projectId, r.Labels["project_id"]);
+            Assert.Equal(s_projectId, uploadedEntries[0].LogNameAsLogName.ProjectId);
         }
 
         [Fact]
@@ -516,7 +517,7 @@ public async Task GcePlatform()
             const string json = @"
 {
   'project': {
-    'projectId': '" + s_projectId + @"'
+    'projectId': 'gce_project_id'
   },
   'instance': {
     'id': 'FakeInstanceId',
@@ -535,15 +536,19 @@ public async Task GcePlatform()
             var r = uploadedEntries[0].Resource;
             Assert.Equal("gce_instance", r.Type);
             Assert.Equal(3, r.Labels.Count);
-            Assert.Equal(s_projectId, r.Labels["project_id"]);
+            // This is the monitored resource project ID.
+            Assert.Equal("gce_project_id", r.Labels["project_id"]);
             Assert.Equal("FakeInstanceId", r.Labels["instance_id"]);
             Assert.Equal("FakeZone", r.Labels["zone"]);
+            // If the project ID is configured, it is used as the target for writing
+            // logs, even if the code is running on GCP.
+            Assert.Equal(s_projectId, uploadedEntries[0].LogNameAsLogName.ProjectId);
         }
 
         [Fact]
         public async Task GaePlatform()
         {
-            var platform = new Platform(new GaePlatformDetails(s_projectId, "FakeInstanceId", "FakeService", "FakeVersion"));
+            var platform = new Platform(new GaePlatformDetails("gae_project_id", "FakeInstanceId", "FakeService", "FakeVersion"));
             var uploadedEntries = await RunTestWorkingServer(
                 googleTarget =>
                 {
@@ -554,9 +559,36 @@ public async Task GaePlatform()
             var r = uploadedEntries[0].Resource;
             Assert.Equal("gae_app", r.Type);
             Assert.Equal(3, r.Labels.Count);
-            Assert.Equal(s_projectId, r.Labels["project_id"]);
+            // This is the monitored resource project ID.
+            Assert.Equal("gae_project_id", r.Labels["project_id"]);
+            Assert.Equal("FakeService", r.Labels["module_id"]);
+            Assert.Equal("FakeVersion", r.Labels["version_id"]);
+            // If the project ID is configured, it is used as the target for writing
+            // logs, even if the code is running on GCP.
+            Assert.Equal(s_projectId, uploadedEntries[0].LogNameAsLogName.ProjectId);
+        }
+
+        [Fact]
+        public async Task GaePlatform_NoConfiguredProjectId()
+        {
+            var platform = new Platform(new GaePlatformDetails("gae_project_id", "FakeInstanceId", "FakeService", "FakeVersion"));
+            var uploadedEntries = await RunTestWorkingServer(
+                googleTarget =>
+                {
+                    LogInfo("Message0");
+                    return Task.FromResult(0);
+                }, platform: platform, enableResourceTypeDetection: true, configFn: target => target.ProjectId = null);
+            Assert.Equal(1, uploadedEntries.Count);
+            var r = uploadedEntries[0].Resource;
+            Assert.Equal("gae_app", r.Type);
+            Assert.Equal(3, r.Labels.Count);
+            // This is the monitored resource project ID.
+            Assert.Equal("gae_project_id", r.Labels["project_id"]);
             Assert.Equal("FakeService", r.Labels["module_id"]);
             Assert.Equal("FakeVersion", r.Labels["version_id"]);
+            // If the project ID is not configured, then the target will be the project where
+            // the monitored resource is at.
+            Assert.Equal("gae_project_id", uploadedEntries[0].LogNameAsLogName.ProjectId);
         }
     }
 }

apis/Google.Cloud.Logging.NLog/Google.Cloud.Logging.NLog/GoogleStackdriverTarget.cs

@@ -288,22 +288,27 @@ private GoogleCredential GetCredentialFromConfiguration()
 
         private void ActivateLogIdAndResource(string logId)
         {
-            string projectId = null;
+            // Project ID of the project where the resource that is being monitored lives.
+            string monitoredProjectId = null;
+            // Project ID of the project where the entries are to be written.
+            string targetProjectId = null;
             MonitoredResource resource = null;
+
             if (!DisableResourceTypeDetection)
             {
                 resource = MonitoredResourceBuilder.FromPlatform(_platform);
-                resource.Labels.TryGetValue("project_id", out projectId);
+                resource.Labels.TryGetValue("project_id", out monitoredProjectId);
             }
+            targetProjectId = ProjectId?.Render(LogEventInfo.CreateNullEvent());
 
-            if (projectId == null)
+            if (monitoredProjectId == null)
             {
                 // Either platform detection is disabled, or it detected an unknown platform.
                 // So use the manually configured projectId and override the resource.
-                projectId = GaxPreconditions.CheckNotNull(ProjectId?.Render(LogEventInfo.CreateNullEvent()), nameof(ProjectId));
+                monitoredProjectId = GaxPreconditions.CheckNotNull(targetProjectId, nameof(ProjectId));
                 if (ResourceType == null)
                 {
-                    resource = new MonitoredResource { Type = "global", Labels = { { "project_id", projectId } } };
+                    resource = new MonitoredResource { Type = "global", Labels = { { "project_id", monitoredProjectId } } };
                 }
                 else
                 {
@@ -312,8 +317,14 @@ private void ActivateLogIdAndResource(string logId)
                 }
             }
 
+            if (targetProjectId == null)
+            {
+                // If there was no configured projectId, then use the same as the monitored resoure.
+                targetProjectId = monitoredProjectId;
+            }
+
             _resource = resource;
-            var logName = new LogName(projectId, logId);
+            var logName = new LogName(targetProjectId, logId);
             _logName = logName.ToString();
             _logNameToWrite = logName;
         }