Tyagiquamar · Oct 25, 2026 · Nov 5, 2026 · github-actions · Oct 25, 2026 · github-actions
@@ -0,0 +1,5 @@
+---
+"@hyperdx/api": patch
+---
+
+fix(api): prevent Slack notification failures when alert message exceeds 3000 chars
@@ -0,0 +1,103 @@
+import {
+  formatSlackSectionText,
+  getFallbackHdxLink,
+  handleSendSlackWebhook,
+} from '@/tasks/checkAlerts/transports/slack';
+import type { Message, WebhookChannel } from '@/tasks/checkAlerts/transports/types';
+import * as slack from '@/utils/slack';
+
+jest.mock('@/utils/slack');
+jest.mock('@/utils/validators');
+
+describe('Slack transport', () => {
+  describe('getFallbackHdxLink', () => {
+    it('returns origin + /alerts for valid URLs', () => {
+      expect(
+        getFallbackHdxLink('https://app.hyperdx.io/chart?config=%7B%22very%22%3A%22long%22%7D'),
+      ).toBe('https://app.hyperdx.io/alerts');
+    });
+
+    it('returns original input if not a valid URL', () => {
+      expect(getFallbackHdxLink('not-a-url')).toBe('not-a-url');
+    });
+  });
+
+  describe('formatSlackSectionText', () => {
+    it('keeps standard link and body when under character limit', () => {
+      const link = 'https://app.hyperdx.io/alerts/123';
+      const title = 'High Error Rate';
+      const body = 'Error rate exceeded 5%';
+      expect(formatSlackSectionText(link, title, body)).toBe(
+        `*<${link} | ${title}>*\n${body}`,
+      );
+    });
+
+    it('falls back to /alerts when large query string exceeds limit', () => {
+      const longQuery = 'x'.repeat(3100);
+      const longLink = `https://app.hyperdx.io/chart?config=${longQuery}`;
+      const title = 'High Latency';
+      const body = 'p99 latency > 500ms';
+      const formatted = formatSlackSectionText(longLink, title, body, 3000);
+
+      expect(formatted).toBe(`*<https://app.hyperdx.io/alerts | ${title}>*\n${body}`);
+      expect(formatted.length).toBeLessThanOrEqual(3000);
+    });
+
+    it('truncates body when text still exceeds limit after fallback link', () => {
+      const longQuery = 'x'.repeat(2900);
+      const longLink = `https://app.hyperdx.io/chart?config=${longQuery}`;
+      const title = 'High Latency';
+      const longBody = 'b'.repeat(3500);
+      const formatted = formatSlackSectionText(longLink, title, longBody, 3000);
+
+      expect(formatted.startsWith(`*<https://app.hyperdx.io/alerts | ${title}>*\n`)).toBe(true);
+      expect(formatted.endsWith('...')).toBe(true);
+      expect(formatted.length).toBeLessThanOrEqual(3000);
+    });
+  });
+
+  describe('handleSendSlackWebhook', () => {
+    it('passes formatted section block text to postMessageToWebhook', async () => {
+      const mockPostMessage = jest.spyOn(slack, 'postMessageToWebhook').mockResolvedValue({} as any);
+
+      const channel: WebhookChannel = {
+        type: 'webhook',
+        channel: {
+          _id: 'wh-1' as any,
+          name: 'Slack Alerts',
+          service: 'slack' as any,
+          url: 'https://hooks.slack.com/services/T00/B00/X00',
+        } as any,
+      };
+
+      const message: Message = {
+        hdxLink: 'https://app.hyperdx.io/chart?config=test',
+        title: 'CPU Alert',
+        body: 'CPU > 90%',
+        state: 'ALERT' as any,
+        startTime: 0,
+        endTime: 1000,
+        eventId: 'evt-1',
+      };
+
+      await handleSendSlackWebhook(channel, message);
+
+      expect(mockPostMessage).toHaveBeenCalledTimes(1);
+      expect(mockPostMessage).toHaveBeenCalledWith(
+        'https://hooks.slack.com/services/T00/B00/X00',
+        {
+          text: 'CPU Alert',
+          blocks: [
+            {
+              type: 'section',
+              text: {
+                type: 'mrkdwn',
+                text: '*<https://app.hyperdx.io/chart?config=test | CPU Alert>*\nCPU > 90%',
+              },
+            },
+          ],
+        },
+      );
+    });
+  });
+});
@@ -13,6 +13,49 @@ import type {
 import * as slack from '@/utils/slack';
 import { validateWebhookUrl } from '@/utils/validators';
 
+const MAX_SLACK_SECTION_LENGTH = 3000;
+
+export const getFallbackHdxLink = (hdxLink: string): string => {
+  try {
+    const url = new URL(hdxLink);
+    return `${url.origin}/alerts`;
+  } catch {
+    return hdxLink;
+  }
+};
+
+export const formatSlackSectionText = (
+  hdxLink: string,
+  title: string,
+  body: string,
+  maxLength = MAX_SLACK_SECTION_LENGTH,
+): string => {
+  let link = hdxLink;
+  let text = `*<${link} | ${title}>*\n${body}`;
+  if (text.length <= maxLength) {
+    return text;
+  }
+
+  // If text exceeds limit, try falling back to the shorter /alerts link
+  const fallbackLink = getFallbackHdxLink(hdxLink);
+  if (fallbackLink !== link) {
+    text = `*<${fallbackLink} | ${title}>*\n${body}`;
+    if (text.length <= maxLength) {
+      return text;
+    }
+    link = fallbackLink;
+  }
+
+  // If still exceeding limit, truncate body with an ellipsis
+  const header = `*<${link} | ${title}>*\n`;
+  const availableBodyLen = maxLength - header.length - 3;
+  if (availableBodyLen > 0) {
+    return `${header}${body.slice(0, availableBodyLen)}...`;
+  }
+
+  return `*<${link} | ${title}>*`.slice(0, maxLength);
+};
+
 export const handleSendSlackWebhook = async (
   channel: WebhookChannel,
   message: Message,
@@ -29,7 +72,11 @@ export const handleSendSlackWebhook = async (
           type: 'section',
           text: {
             type: 'mrkdwn',
-            text: `*<${message.hdxLink} | ${message.title}>*\n${message.body}`,
+            text: formatSlackSectionText(
+              message.hdxLink,
+              message.title,
+              message.body,
+            ),
           },
         },
       ],