add DbBasis service

Signed-off-by: Alexandra Pereira <[email protected]>

src/gxtdb/service.clj

@@ -31,6 +31,7 @@
 ;;   returns details about the transactor and the speculated result.
 ;; - entity: returns an entity document.
 ;; - entity-tx: return an entity transaction information.
+;; - db-basis: returns the basis of this db snapshot - a map containing `xt/valid-time` and `xt/tx`
 (deftype GrpcAPI [xtdb-node]
   api/Service
   (SubmitTx [_this {{:keys [tx-ops tx-time]} :grpc-params}]
@@ -50,6 +51,10 @@
     (let [status (xt/status xtdb-node)]
       {:status 200
        :body  (status-adapter/edn->grpc status)})))
+  (BbBasis
+    [_this {params :grpc-params}]
+      {:status 200
+      :body (controllers/db-basis xtdb-node)})
 
 (def common-interceptors [(body-params/body-params) http/html-body])