feat: unregister webhook upon deleting flow

packages/backend/src/graphql/mutations/delete-flow.ts

@@ -1,6 +1,8 @@
 import Context from '../../types/express/context';
 import Execution from '../../models/execution';
 import ExecutionStep from '../../models/execution-step';
+import globalVariable from '../../helpers/global-variable';
+import logger from '../../helpers/logger';
 
 type Params = {
   input: {
@@ -22,6 +24,25 @@ const deleteFlow = async (
     })
     .throwIfNotFound();
 
+  const triggerStep = await flow.getTriggerStep();
+  const trigger = await triggerStep.getTriggerCommand();
+
+  if (trigger.type === 'webhook' && trigger?.unregisterHook) {
+    const $ = await globalVariable({
+      flow,
+      connection: await triggerStep.$relatedQuery('connection'),
+      app: await triggerStep.getApp(),
+      step: triggerStep,
+    });
+
+    try {
+      await trigger.unregisterHook($);
+    } catch (error) {
+      // suppress error as the remote resource might have been already deleted
+      logger.debug(`Failed to unregister webhook for flow ${flow.id}: ${error.message}`);
+    }
+  }
+
   const executionIds = (
     await flow.$relatedQuery('executions').select('executions.id')
   ).map((execution: Execution) => execution.id);