From 7d0bb2ec059e87f6c26f6a062398ef0f8ced1bcf Mon Sep 17 00:00:00 2001
From: Marcos Candeia <marrcooos@gmail.com>
Date: Sat, 19 Oct 2024 18:00:49 -0300
Subject: [PATCH] Add actor error handling

Signed-off-by: Marcos Candeia <marrcooos@gmail.com>
---
 src/actors/proxy.ts     |  8 ++++++--
 src/actors/proxyutil.ts | 24 ++++++++++++++++++++++--
 src/actors/runtime.ts   | 15 +++++++++++++++
 3 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/src/actors/proxy.ts b/src/actors/proxy.ts
index 8703fb3..d2e8f6e 100644
--- a/src/actors/proxy.ts
+++ b/src/actors/proxy.ts
@@ -6,15 +6,19 @@ export interface ActorsServer {
   deploymentId?: string;
 }
 
+export interface ActorsOptions {
+  server?: ActorsServer;
+  errorHandling?: Record<string, new (...args: unknown[]) => Error>;
+}
 /**
  * utilities to create and manage actors.
  */
 export const actors = {
   proxy: <TInstance extends Actor>(
     actor: ActorConstructor<TInstance> | string,
-    server?: ActorsServer | undefined,
+    options?: ActorsOptions | undefined,
   ): { id: (id: string) => Promisify<TInstance> } => {
-    const factory = (id: string) => createHttpInvoker(id, server);
+    const factory = (id: string) => createHttpInvoker(id, options);
     return create(actor, factory);
   },
 };
diff --git a/src/actors/proxyutil.ts b/src/actors/proxyutil.ts
index 7c77c38..39a6ce4 100644
--- a/src/actors/proxyutil.ts
+++ b/src/actors/proxyutil.ts
@@ -1,4 +1,4 @@
-import type { ActorsServer } from "./proxy.ts";
+import type { ActorsOptions, ActorsServer } from "./proxy.ts";
 import type { Actor, ActorConstructor } from "./runtime.ts";
 import { EVENT_STREAM_RESPONSE_HEADER, readFromStream } from "./stream.ts";
 import {
@@ -9,6 +9,7 @@ import {
 
 export const ACTOR_ID_HEADER_NAME = "x-deno-isolate-instance-id";
 export const ACTOR_ID_QS_NAME = "deno_isolate_instance_id";
+export const ACTOR_CONSTRUCTOR_NAME_HEADER = "x-error-constructor-name";
 /**
  * Promise.prototype.then onfufilled callback type.
  */
@@ -177,8 +178,9 @@ export const createHttpInvoker = <
   TChannel extends DuplexChannel<unknown, unknown>,
 >(
   actorId: string,
-  server?: ActorsServer,
+  options?: ActorsOptions,
 ): ActorInvoker<TResponse, TChannel> => {
+  const server = options?.server;
   if (!server) {
     _server ??= initServer();
   }
@@ -214,6 +216,24 @@ export const createHttpInvoker = <
           }),
         },
       );
+      if (!resp.ok) {
+        const constructorName = resp.headers.get(ACTOR_CONSTRUCTOR_NAME_HEADER);
+        const ErrorConstructor =
+          options?.errorHandling?.[constructorName ?? "Error"] ?? Error;
+        const errorParameters =
+          resp.headers.get("content-type")?.includes("application/json")
+            ? await resp.json()
+            : {
+              message: await resp.text().catch(() =>
+                `HTTP Error: ${resp.statusText}`
+              ),
+            };
+        const deserializedError = Object.assign(
+          new ErrorConstructor(),
+          errorParameters,
+        );
+        throw deserializedError;
+      }
       if (
         resp.headers.get("content-type") ===
           EVENT_STREAM_RESPONSE_HEADER
diff --git a/src/actors/runtime.ts b/src/actors/runtime.ts
index 87a9970..fb7c7de 100644
--- a/src/actors/runtime.ts
+++ b/src/actors/runtime.ts
@@ -1,6 +1,7 @@
 import { type ServerSentEventMessage, ServerSentEventStream } from "@std/http";
 import { ActorError } from "./errors.ts";
 import {
+  ACTOR_CONSTRUCTOR_NAME_HEADER,
   ACTOR_ID_HEADER_NAME,
   ACTOR_ID_QS_NAME,
   type ActorInvoker,
@@ -278,6 +279,20 @@ export class ActorRuntime {
           }[err.code] ?? 500,
         });
       }
+      const constructorName = err?.constructor?.name;
+      if (constructorName) {
+        const serializedError = JSON.stringify(
+          err,
+          Object.getOwnPropertyNames(err),
+        );
+        return new Response(serializedError, {
+          status: 500,
+          headers: {
+            [ACTOR_CONSTRUCTOR_NAME_HEADER]: constructorName,
+            "content-type": "application/json",
+          },
+        });
+      }
       throw err;
     }
   }