CloudWatch Logs: Fix running logs queries with expressions (#65306)

packages/grafana-runtime/src/utils/DataSourceWithBackend.test.ts

@@ -103,6 +103,61 @@ describe('DataSourceWithBackend', () => {
     `);
   });
 
+  test('correctly creates expression queries', () => {
+    const { mock, ds } = createMockDatasource();
+    ds.query({
+      maxDataPoints: 10,
+      intervalMs: 5000,
+      targets: [{ refId: 'A' }, { refId: 'B', datasource: { type: '__expr__' } }],
+      dashboardUID: 'dashA',
+      panelId: 123,
+      queryGroupId: 'abc',
+    } as DataQueryRequest);
+
+    const args = mock.calls[0][0];
+
+    expect(mock.calls.length).toBe(1);
+    expect(args).toMatchInlineSnapshot(`
+      {
+        "data": {
+          "queries": [
+            {
+              "datasource": {
+                "type": "dummy",
+                "uid": "abc",
+              },
+              "datasourceId": 1234,
+              "intervalMs": 5000,
+              "maxDataPoints": 10,
+              "queryCachingTTL": undefined,
+              "refId": "A",
+            },
+            {
+              "datasource": {
+                "name": "Expression",
+                "type": "__expr__",
+                "uid": "__expr__",
+              },
+              "refId": "B",
+            },
+          ],
+        },
+        "headers": {
+          "X-Dashboard-Uid": "dashA",
+          "X-Datasource-Uid": "abc",
+          "X-Grafana-From-Expr": "true",
+          "X-Panel-Id": "123",
+          "X-Plugin-Id": "dummy",
+          "X-Query-Group-Id": "abc",
+        },
+        "hideFromInspector": false,
+        "method": "POST",
+        "requestId": undefined,
+        "url": "/api/ds/query?expression=true",
+      }
+    `);
+  });
+
   test('should apply template variables only for the current data source', () => {
     const { mock, ds } = createMockDatasource();
     ds.applyTemplateVariables = jest.fn();

packages/grafana-runtime/src/utils/DataSourceWithBackend.ts

@@ -78,6 +78,7 @@ enum PluginRequestHeaders {
   DashboardUID = 'X-Dashboard-Uid', // mainly useful for debuging slow queries
   PanelID = 'X-Panel-Id', // mainly useful for debuging slow queries
   QueryGroupID = 'X-Query-Group-Id', // mainly useful to find related queries with query chunking
+  FromExpression = 'X-Grafana-From-Expr', // used by datasources to identify expression queries
 }
 
 /**
@@ -197,14 +198,16 @@ class DataSourceWithBackend<
       });
     }
 
-    let url = '/api/ds/query';
-    if (hasExpr) {
-      url += '?expression=true';
-    }
-
     const headers: Record<string, string> = {};
     headers[PluginRequestHeaders.PluginID] = Array.from(pluginIDs).join(', ');
     headers[PluginRequestHeaders.DatasourceUID] = Array.from(dsUIDs).join(', ');
+
+    let url = '/api/ds/query';
+    if (hasExpr) {
+      headers[PluginRequestHeaders.FromExpression] = 'true';
+      url += '?expression=true';
+    }
+
     if (request.dashboardUID) {
       headers[PluginRequestHeaders.DashboardUID] = request.dashboardUID;
     }