QueryService: Add feature toggles to better support testing (#86493)

2024-04-19 12:26:21 +03:00
parent 8a5c0cfdc0
commit 5a8384a245
14 changed files with 191 additions and 42 deletions
@@ -0,0 +1,78 @@
+# Query service
+
+This query service aims to replace the existing /api/ds/query.  
+
+The key differences are:
+1. This service has a stronger type system (not simplejson)
+2. Same workflow regardless if expressions exist
+3. Datasource settings+access is managed in each datasource, not at the beginning
+
+
+
+### Current /api/ds/query workflow
+
+```mermaid
+sequenceDiagram
+    autonumber
+    actor User as User or Process
+    participant api as /api/ds/query
+    participant db as Storage<br/>(SQL)
+    participant ds as Datasource<br/>Plugin
+    participant expr as Expression<br/>Engine
+
+    User->>api: POST Query
+    loop Each query
+        api->>api: Parse query
+        api->>db: Get ds config<br>and secrets
+        db->>api: 
+    end
+    alt No expressions
+      alt Single datasource
+          api->>ds: QueryData
+      else Multiple datasources
+        loop Each datasource (concurrently)
+          api->>ds: QueryData
+        end
+        api->>api: Wait for results
+      end
+    else Expressions exist
+        api->>expr: Calculate expressions graph
+        loop Each node (eg, refID)
+          alt Is query
+              expr->>ds: QueryData
+          else Is expression
+            expr->>expr: Process
+          end
+        end
+    end
+    api->>User: return results
+```
+
+
+
+### /apis/query.grafana.app (in single tenant grafana)
+
+```mermaid
+sequenceDiagram
+    autonumber
+    actor User as User or Process
+    participant api as /apis/query.grafana.app
+    participant ds as Datasource<br/>Handler/Plugin
+    participant db as Storage<br/>(SQL)
+    participant expr as Expression<br/>Engine
+
+    User->>api: POST Query
+    api->>api: Parse queries
+    api->>api: Calculate dependencies
+    loop Each datasource (concurrently)
+        api->>ds: QueryData
+        ds->>ds: Verify user access
+        ds->>db: Get settings <br> and secrets
+    end
+    loop Each expression
+        api->>expr: Execute
+    end
+    api->>api: Verify ResultExpectations
+    api->>User: return results
+```
+