From c65e7584088cb3e8adb4a97977b11373e8275f6f Mon Sep 17 00:00:00 2001
From: Brian Botha <brian.botha@matrix.ai>
Date: Fri, 16 Sep 2022 14:08:43 +1000
Subject: [PATCH] feat: added handler to detect promise deadlocks to
 `ExitHandlers.ts`

#307
---
 src/bin/errors.ts             |  7 +++++++
 src/bin/utils/ExitHandlers.ts | 16 ++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/src/bin/errors.ts b/src/bin/errors.ts
index be6876a65..576fa21a6 100644
--- a/src/bin/errors.ts
+++ b/src/bin/errors.ts
@@ -49,6 +49,12 @@ class ErrorCLIPolykeyAgentProcess<T> extends ErrorCLI<T> {
   exitCode = sysexits.OSERR;
 }
 
+class ErrorCLIPolykeyAsynchronousDeadlock<T> extends ErrorCLI<T> {
+  static description =
+    'PolykeyAgent process exited unexpectedly, likely due to promise deadlock';
+  exitCode = sysexits.SOFTWARE;
+}
+
 class ErrorNodeFindFailed<T> extends ErrorCLI<T> {
   static description = 'Failed to find the node in the DHT';
   exitCode = 1;
@@ -70,6 +76,7 @@ export {
   ErrorCLIFileRead,
   ErrorCLIPolykeyAgentStatus,
   ErrorCLIPolykeyAgentProcess,
+  ErrorCLIPolykeyAsynchronousDeadlock,
   ErrorNodeFindFailed,
   ErrorNodePingFailed,
 };
diff --git a/src/bin/utils/ExitHandlers.ts b/src/bin/utils/ExitHandlers.ts
index 2fdd74f03..24fa27871 100644
--- a/src/bin/utils/ExitHandlers.ts
+++ b/src/bin/utils/ExitHandlers.ts
@@ -1,6 +1,7 @@
 import process from 'process';
 import * as binUtils from './utils';
 import ErrorPolykey from '../../ErrorPolykey';
+import * as CLIErrors from '../errors';
 
 class ExitHandlers {
   /**
@@ -84,6 +85,19 @@ class ExitHandlers {
     }
   };
 
+  protected deadlockHandler = async () => {
+    if (process.exitCode == null) {
+      const e = new CLIErrors.ErrorCLIPolykeyAsynchronousDeadlock();
+      process.stderr.write(
+        binUtils.outputFormatter({
+          type: this._errFormat,
+          data: e,
+        }),
+      );
+      process.exitCode = e.exitCode;
+    }
+  };
+
   /**
    * Automatically installs all handlers
    */
@@ -110,6 +124,7 @@ class ExitHandlers {
     // Both synchronous and asynchronous errors are handled
     process.once('unhandledRejection', this.errorHandler);
     process.once('uncaughtException', this.errorHandler);
+    process.once('beforeExit', this.deadlockHandler);
   }
 
   public uninstall() {
@@ -119,6 +134,7 @@ class ExitHandlers {
     process.removeListener('SIGHUP', this.signalHandler);
     process.removeListener('unhandledRejection', this.errorHandler);
     process.removeListener('uncaughtException', this.errorHandler);
+    process.removeListener('beforeExit', this.deadlockHandler);
   }
 
   /**