doc: add a service structure graph

README.md

@@ -22,3 +22,61 @@ A working-in-progress collaborative online image/manga translation platform base
 | `web`        | Website                    |
 | `web-ext`    | Browser extension          |
 | `userscript` | UserScript                 |
+
+#### Service structure
+
+```mermaid
+flowchart TB
+
+browser <--> |HTTP| web["web @ cotrans.touhou.ai"]
+
+userscript <--> |HTTP| web
+
+browser <--> |HTTP,WS| wk-gateway["wk-gateway @ api.cotrans.touhou.ai"]
+
+wk-gateway --> doImage
+wk-gateway --> doMitWorker
+wk-gateway --> cotrans
+wk-gateway --> wkr2-private
+wk-gateway --> wkr2-public
+
+wk-gateway-domitworker --> doMitWorker
+wk-gateway-domitworker --> cotrans
+
+wk-image --> cotrans-private
+wk-image --> doImage
+
+wkr2-public <--> cotrans-public[cotrans-public: images]
+wkr2-private <--> cotrans-private[cotrans-private: images]
+
+subgraph pages[CF page]
+    web
+end
+
+subgraph workers[CF worker]
+    wk-gateway
+    wk-gateway-domitworker
+    wk-image
+    wkr2-public
+    wkr2-private
+end
+
+subgraph do["CF durable object"]
+    doMitWorker
+    doImage
+end
+
+subgraph d1["CF D1 database"]
+    cotrans[Relational DB for translation tasks]
+end
+
+subgraph buckets["CF buckets"]
+    cotrans-public
+    cotrans-private
+end
+
+workers --> do
+do --> buckets
+do --> d1
+
+```