[Clojure] Improve Error Handling

[naomijub]

As a User
I want to have proper error handling in the Clojure gRPC side
Currently we rely on Protojure grpc interceptor to handle errors
So we need to implement an interceptor to handle gXTDB errors as well as XDTB transaction errors

[naomijub]

;; protojure/pedestal/interceptor/grpc.clj
(def error-interceptor
  (err/error-dispatch
   [ctx ex]

   [{:exception-type ::status/error}]
   (let [{:keys [code msg]} (ex-data ex)]
     (err-status ctx code msg))

   :else
   (err-status ctx (grpc.status/get-code :internal) (ex-message ex))))

;; protojure/pedestal/routes.clj
(defn ->tablesyntax
  "Generates routes in [Table Syntax](http://pedestal.io/reference/table-syntax) format"
  [{:keys [rpc-metadata interceptors callback-context] :as options}]
  (for [{:keys [pkg service method method-fn] :as rpc} rpc-metadata]
    (let [fqs (str pkg "." service)
          name (keyword fqs (str method "-handler"))
          handler (handler name (partial method-fn callback-context))]
      [(str "/" fqs "/" method)
       :post (-> (consv grpc/error-interceptor interceptors)
                 (conj grpc.web/proxy
                       (grpc/route-interceptor rpc)
                       handler))
       :route-name name])))

;; gxtdb.service.clj
(defn grpc-routes [xtdb-node] (reduce conj routes (proutes/->tablesyntax {:rpc-metadata api/rpc-metadata :interceptors common-interceptors :callback-context (GrpcAPI. xtdb-node)})))