From f058c7edcb4ef3511b99394aff037419c85c8278 Mon Sep 17 00:00:00 2001
From: gnuxie <gnuxie@element.io>
Date: Thu, 31 Mar 2022 16:52:28 +0100
Subject: [PATCH] Make startup failures more controlled and understandable.

There is no reason to call process.exit() from `index.ts` or in `Mjolnir.start()` because

https://nodejs.org/api/process.html#warning-using-uncaughtexception-correctly

>The 'uncaughtException' event is emitted when an uncaught JavaScript exception bubbles all the way back to the event loop. By default, Node.js handles such exceptions by printing the stack trace to stderr and exiting with code 1, overriding any previously set process.exitCode. Adding a handler for the 'uncaughtException' event overrides this default behaviour.
---
 src/Mjolnir.ts | 7 ++++---
 src/index.ts   | 9 +++++++--
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/src/Mjolnir.ts b/src/Mjolnir.ts
index d27292c..3c1c098 100644
--- a/src/Mjolnir.ts
+++ b/src/Mjolnir.ts
@@ -320,11 +320,12 @@ export class Mjolnir {
             try {
                 LogService.error("Mjolnir", "Error during startup:");
                 LogService.error("Mjolnir", extractRequestError(err));
+                this.stop();
                 await this.logMessage(LogLevel.ERROR, "Mjolnir@startup", "Startup failed due to error - see console");
+                throw err;
             } catch (e) {
-                // If we failed to handle the error, just crash
-                console.error(e);
-                process.exit(1);
+                LogService.error("Mjolnir", `Failed to report startup error to the management room: ${e}`);
+                throw err;
             }
         }
     }
diff --git a/src/index.ts b/src/index.ts
index e6896a0..0ed071f 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -57,9 +57,14 @@ if (config.health.healthz.enabled) {
         config.RUNTIME.client = client;
 
         bot = await Mjolnir.setupMjolnirFromConfig(client);
+    } catch (err) {
+        console.error(`Failed to setup mjolnir from the config ${config.dataPath}: ${err}`);
+        throw err;
+    }
+    try {
         await bot.start();
     } catch (err) {
-        bot?.logMessage(LogLevel.ERROR, "index", err);
-        process.exit(1);
+        console.error(`Mjolnir failed to start: ${err}`);
+        throw err;
     }
 })();